diff --git a/Android.bp b/Android.bp
index 3b8ef61..8b53bf1 100644
--- a/Android.bp
+++ b/Android.bp
@@ -362,6 +362,7 @@
         "tv_tuner_resource_manager_aidl_interface-java",
         "soundtrigger_middleware-aidl-java",
         "modules-utils-preconditions",
+        "modules-utils-synchronous-result-receiver",
         "modules-utils-os",
         "framework-permission-aidl-java",
         "spatializer-aidl-java",
diff --git a/core/java/android/bluetooth/BluetoothA2dp.java b/core/java/android/bluetooth/BluetoothA2dp.java
index d66dc63..8b9cec1 100644
--- a/core/java/android/bluetooth/BluetoothA2dp.java
+++ b/core/java/android/bluetooth/BluetoothA2dp.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -30,17 +32,19 @@
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.Build;
 import android.os.IBinder;
 import android.os.ParcelUuid;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 
 /**
@@ -271,7 +275,7 @@
                     IBluetoothA2dp.class.getName()) {
                 @Override
                 public IBluetoothA2dp getServiceInterface(IBinder service) {
-                    return IBluetoothA2dp.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothA2dp.Stub.asInterface(service);
                 }
     };
 
@@ -322,17 +326,21 @@
     @UnsupportedAppUsage
     public boolean connect(BluetoothDevice device) {
         if (DBG) log("connect(" + device + ")");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled() && isValidDevice(device)) {
-                return service.connect(device);
+        final IBluetoothA2dp service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connectWithAttribution(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -364,17 +372,21 @@
     @UnsupportedAppUsage
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled() && isValidDevice(device)) {
-                return service.disconnect(device);
+        final IBluetoothA2dp service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnectWithAttribution(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -385,19 +397,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothDevice> getConnectedDevices() {
         if (VDBG) log("getConnectedDevices()");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
+        final IBluetoothA2dp service = getService();
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevicesWithAttribution(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevicesWithAttribution(mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return new ArrayList<BluetoothDevice>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new ArrayList<BluetoothDevice>();
         }
+        return defaultValue;
     }
 
     /**
@@ -408,20 +425,25 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (VDBG) log("getDevicesMatchingStates()");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
+        final IBluetoothA2dp service = getService();
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStatesWithAttribution(states,
+                        mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStatesWithAttribution(states,
-                                mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return new ArrayList<BluetoothDevice>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new ArrayList<BluetoothDevice>();
         }
+        return defaultValue;
     }
 
     /**
@@ -432,18 +454,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public @BtProfileState int getConnectionState(BluetoothDevice device) {
         if (VDBG) log("getState(" + device + ")");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                return service.getConnectionState(device);
+        final IBluetoothA2dp service = getService();
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionStateWithAttribution(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return BluetoothProfile.STATE_DISCONNECTED;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return BluetoothProfile.STATE_DISCONNECTED;
         }
+        return defaultValue;
     }
 
     /**
@@ -471,18 +496,21 @@
     @UnsupportedAppUsage(trackingBug = 171933273)
     public boolean setActiveDevice(@Nullable BluetoothDevice device) {
         if (DBG) log("setActiveDevice(" + device + ")");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()
-                    && ((device == null) || isValidDevice(device))) {
-                return service.setActiveDevice(device, mAttributionSource);
+        final IBluetoothA2dp service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && ((device == null) || isValidDevice(device))) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setActiveDevice(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -499,18 +527,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public BluetoothDevice getActiveDevice() {
         if (VDBG) log("getActiveDevice()");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
+        final IBluetoothA2dp service = getService();
+        final BluetoothDevice defaultValue = null;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<BluetoothDevice> recv =
+                        new SynchronousResultReceiver();
+                service.getActiveDevice(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getActiveDevice(mAttributionSource), mAttributionSource);
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return null;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return null;
         }
+        return defaultValue;
     }
 
     /**
@@ -555,22 +589,23 @@
     public boolean setConnectionPolicy(@NonNull BluetoothDevice device,
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                        && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                    return false;
-                }
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
+        final IBluetoothA2dp service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                    && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                        || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -589,19 +624,7 @@
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
     public int getPriority(BluetoothDevice device) {
         if (VDBG) log("getPriority(" + device + ")");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                return BluetoothAdapter.connectionPolicyToPriority(
-                        service.getPriority(device, mAttributionSource));
-            }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return BluetoothProfile.PRIORITY_OFF;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return BluetoothProfile.PRIORITY_OFF;
-        }
+        return BluetoothAdapter.connectionPolicyToPriority(getConnectionPolicy(device));
     }
 
     /**
@@ -623,18 +646,21 @@
     })
     public @ConnectionPolicy int getConnectionPolicy(@NonNull BluetoothDevice device) {
         if (VDBG) log("getConnectionPolicy(" + device + ")");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                return service.getConnectionPolicy(device, mAttributionSource);
+        final IBluetoothA2dp service = getService();
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
         }
+        return defaultValue;
     }
 
     /**
@@ -646,17 +672,21 @@
     @RequiresNoPermission
     public boolean isAvrcpAbsoluteVolumeSupported() {
         if (DBG) Log.d(TAG, "isAvrcpAbsoluteVolumeSupported");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
-                return service.isAvrcpAbsoluteVolumeSupported();
+        final IBluetoothA2dp service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isAvrcpAbsoluteVolumeSupported(recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Error talking to BT service in isAvrcpAbsoluteVolumeSupported()", e);
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -669,14 +699,16 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public void setAvrcpAbsoluteVolume(int volume) {
         if (DBG) Log.d(TAG, "setAvrcpAbsoluteVolume");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
+        final IBluetoothA2dp service = getService();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
                 service.setAvrcpAbsoluteVolume(volume, mAttributionSource);
+            } catch (RemoteException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-        } catch (RemoteException e) {
-            Log.e(TAG, "Error talking to BT service in setAvrcpAbsoluteVolume()", e);
         }
     }
 
@@ -689,18 +721,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean isA2dpPlaying(BluetoothDevice device) {
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                return service.isA2dpPlaying(device, mAttributionSource);
+        if (DBG) log("isA2dpPlaying(" + device + ")");
+        final IBluetoothA2dp service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isA2dpPlaying(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -729,8 +765,7 @@
     /**
      * Gets the current codec status (configuration and capability).
      *
-     * @param device the remote Bluetooth device. If null, use the current
-     * active A2DP Bluetooth device.
+     * @param device the remote Bluetooth device.
      * @return the current codec status
      * @hide
      */
@@ -742,26 +777,28 @@
     public BluetoothCodecStatus getCodecStatus(@NonNull BluetoothDevice device) {
         if (DBG) Log.d(TAG, "getCodecStatus(" + device + ")");
         verifyDeviceNotNull(device, "getCodecStatus");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
-                return service.getCodecStatus(device, mAttributionSource);
+        final IBluetoothA2dp service = getService();
+        final BluetoothCodecStatus defaultValue = null;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<BluetoothCodecStatus> recv =
+                        new SynchronousResultReceiver();
+                service.getCodecStatus(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) {
-                Log.w(TAG, "Proxy not attached to service");
-            }
-            return null;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Error talking to BT service in getCodecStatus()", e);
-            return null;
         }
+        return defaultValue;
     }
 
     /**
      * Sets the codec configuration preference.
      *
-     * @param device the remote Bluetooth device. If null, use the current
-     * active A2DP Bluetooth device.
+     * @param device the remote Bluetooth device.
      * @param codecConfig the codec configuration preference
      * @hide
      */
@@ -777,24 +814,23 @@
             Log.e(TAG, "setCodecConfigPreference: Codec config can't be null");
             throw new IllegalArgumentException("codecConfig cannot be null");
         }
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
+        final IBluetoothA2dp service = getService();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
                 service.setCodecConfigPreference(device, codecConfig, mAttributionSource);
+            } catch (RemoteException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Error talking to BT service in setCodecConfigPreference()", e);
-            return;
         }
     }
 
     /**
      * Enables the optional codecs.
      *
-     * @param device the remote Bluetooth device. If null, use the currect
-     * active A2DP Bluetooth device.
+     * @param device the remote Bluetooth device.
      * @hide
      */
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
@@ -810,8 +846,7 @@
     /**
      * Disables the optional codecs.
      *
-     * @param device the remote Bluetooth device. If null, use the currect
-     * active A2DP Bluetooth device.
+     * @param device the remote Bluetooth device.
      * @hide
      */
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
@@ -827,26 +862,25 @@
     /**
      * Enables or disables the optional codecs.
      *
-     * @param device the remote Bluetooth device. If null, use the currect
-     * active A2DP Bluetooth device.
+     * @param device the remote Bluetooth device.
      * @param enable if true, enable the optional codecs, other disable them
      */
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     private void enableDisableOptionalCodecs(BluetoothDevice device, boolean enable) {
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
+        final IBluetoothA2dp service = getService();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
                 if (enable) {
                     service.enableOptionalCodecs(device, mAttributionSource);
                 } else {
                     service.disableOptionalCodecs(device, mAttributionSource);
                 }
+            } catch (RemoteException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Error talking to BT service in enableDisableOptionalCodecs()", e);
-            return;
         }
     }
 
@@ -864,18 +898,23 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     @OptionalCodecsSupportStatus
     public int isOptionalCodecsSupported(@NonNull BluetoothDevice device) {
+        if (DBG) log("isOptionalCodecsSupported(" + device + ")");
         verifyDeviceNotNull(device, "isOptionalCodecsSupported");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled() && isValidDevice(device)) {
-                return service.supportsOptionalCodecs(device, mAttributionSource);
+        final IBluetoothA2dp service = getService();
+        final int defaultValue = OPTIONAL_CODECS_SUPPORT_UNKNOWN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.supportsOptionalCodecs(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return OPTIONAL_CODECS_SUPPORT_UNKNOWN;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Error talking to BT service in supportsOptionalCodecs()", e);
-            return OPTIONAL_CODECS_SUPPORT_UNKNOWN;
         }
+        return defaultValue;
     }
 
     /**
@@ -892,18 +931,23 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     @OptionalCodecsPreferenceStatus
     public int isOptionalCodecsEnabled(@NonNull BluetoothDevice device) {
+        if (DBG) log("isOptionalCodecsEnabled(" + device + ")");
         verifyDeviceNotNull(device, "isOptionalCodecsEnabled");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled() && isValidDevice(device)) {
-                return service.getOptionalCodecsEnabled(device, mAttributionSource);
+        final IBluetoothA2dp service = getService();
+        final int defaultValue = OPTIONAL_CODECS_PREF_UNKNOWN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getOptionalCodecsEnabled(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return OPTIONAL_CODECS_PREF_UNKNOWN;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Error talking to BT service in getOptionalCodecsEnabled()", e);
-            return OPTIONAL_CODECS_PREF_UNKNOWN;
         }
+        return defaultValue;
     }
 
     /**
@@ -921,24 +965,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public void setOptionalCodecsEnabled(@NonNull BluetoothDevice device,
             @OptionalCodecsPreferenceStatus int value) {
+        if (DBG) log("setOptionalCodecsEnabled(" + device + ")");
         verifyDeviceNotNull(device, "setOptionalCodecsEnabled");
-        try {
-            if (value != BluetoothA2dp.OPTIONAL_CODECS_PREF_UNKNOWN
-                    && value != BluetoothA2dp.OPTIONAL_CODECS_PREF_DISABLED
-                    && value != BluetoothA2dp.OPTIONAL_CODECS_PREF_ENABLED) {
-                Log.e(TAG, "Invalid value passed to setOptionalCodecsEnabled: " + value);
-                return;
-            }
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
+        if (value != BluetoothA2dp.OPTIONAL_CODECS_PREF_UNKNOWN
+                && value != BluetoothA2dp.OPTIONAL_CODECS_PREF_DISABLED
+                && value != BluetoothA2dp.OPTIONAL_CODECS_PREF_ENABLED) {
+            Log.e(TAG, "Invalid value passed to setOptionalCodecsEnabled: " + value);
+            return;
+        }
+        final IBluetoothA2dp service = getService();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
                 service.setOptionalCodecsEnabled(device, value, mAttributionSource);
+            } catch (RemoteException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return;
         }
     }
 
@@ -961,17 +1005,21 @@
     })
     public @Type int getDynamicBufferSupport() {
         if (VDBG) log("getDynamicBufferSupport()");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
-                return service.getDynamicBufferSupport(mAttributionSource);
+        final IBluetoothA2dp service = getService();
+        final int defaultValue = DYNAMIC_BUFFER_SUPPORT_NONE;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getDynamicBufferSupport(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return DYNAMIC_BUFFER_SUPPORT_NONE;
-        } catch (RemoteException e) {
-            Log.e(TAG, "failed to get getDynamicBufferSupport, error: ", e);
-            return DYNAMIC_BUFFER_SUPPORT_NONE;
         }
+        return defaultValue;
     }
 
     /**
@@ -992,17 +1040,22 @@
     })
     public @Nullable BufferConstraints getBufferConstraints() {
         if (VDBG) log("getBufferConstraints()");
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
-                return service.getBufferConstraints(mAttributionSource);
+        final IBluetoothA2dp service = getService();
+        final BufferConstraints defaultValue = null;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<BufferConstraints> recv =
+                        new SynchronousResultReceiver();
+                service.getBufferConstraints(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return null;
-        } catch (RemoteException e) {
-            Log.e(TAG, "", e);
-            return null;
         }
+        return defaultValue;
     }
 
     /**
@@ -1027,17 +1080,21 @@
             Log.e(TAG, "Trying to set audio buffer length to a negative value: " + value);
             return false;
         }
-        try {
-            final IBluetoothA2dp service = getService();
-            if (service != null && isEnabled()) {
-                return service.setBufferLengthMillis(codec, value, mAttributionSource);
+        final IBluetoothA2dp service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setBufferLengthMillis(codec, value, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "", e);
-            return false;
         }
+        return defaultValue;
     }
 
     /**
diff --git a/core/java/android/bluetooth/BluetoothA2dpSink.java b/core/java/android/bluetooth/BluetoothA2dpSink.java
index 924dc55..5941681 100755
--- a/core/java/android/bluetooth/BluetoothA2dpSink.java
+++ b/core/java/android/bluetooth/BluetoothA2dpSink.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.NonNull;
 import android.annotation.RequiresPermission;
@@ -29,14 +31,16 @@
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.Build;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the public APIs to control the Bluetooth A2DP Sink
@@ -86,7 +90,7 @@
                     "BluetoothA2dpSink", IBluetoothA2dpSink.class.getName()) {
                 @Override
                 public IBluetoothA2dpSink getServiceInterface(IBinder service) {
-                    return IBluetoothA2dpSink.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothA2dpSink.Stub.asInterface(service);
                 }
     };
 
@@ -140,16 +144,20 @@
     public boolean connect(BluetoothDevice device) {
         if (DBG) log("connect(" + device + ")");
         final IBluetoothA2dpSink service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.connect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -181,16 +189,20 @@
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
         final IBluetoothA2dpSink service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.disconnect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -204,17 +216,23 @@
     public List<BluetoothDevice> getConnectedDevices() {
         if (VDBG) log("getConnectedDevices()");
         final IBluetoothA2dpSink service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -228,18 +246,23 @@
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (VDBG) log("getDevicesMatchingStates()");
         final IBluetoothA2dpSink service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -251,18 +274,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public int getConnectionState(BluetoothDevice device) {
-        if (VDBG) log("getState(" + device + ")");
+        if (VDBG) log("getConnectionState(" + device + ")");
         final IBluetoothA2dpSink service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -282,16 +309,21 @@
     public BluetoothAudioConfig getAudioConfig(BluetoothDevice device) {
         if (VDBG) log("getAudioConfig(" + device + ")");
         final IBluetoothA2dpSink service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final BluetoothAudioConfig defaultValue = null;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getAudioConfig(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return null;
+                final SynchronousResultReceiver<BluetoothAudioConfig> recv =
+                        new SynchronousResultReceiver();
+                service.getAudioConfig(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return null;
+        return defaultValue;
     }
 
     /**
@@ -337,20 +369,22 @@
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
         final IBluetoothA2dpSink service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                    && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                return false;
-            }
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
             try {
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -393,16 +427,20 @@
     public @ConnectionPolicy int getConnectionPolicy(@NonNull BluetoothDevice device) {
         if (VDBG) log("getConnectionPolicy(" + device + ")");
         final IBluetoothA2dpSink service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionPolicy(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        return defaultValue;
     }
 
     /**
@@ -420,17 +458,22 @@
             android.Manifest.permission.BLUETOOTH_PRIVILEGED,
     })
     public boolean isAudioPlaying(@NonNull BluetoothDevice device) {
+        if (VDBG) log("isAudioPlaying(" + device + ")");
         final IBluetoothA2dpSink service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.isA2dpPlaying(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isA2dpPlaying(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
diff --git a/core/java/android/bluetooth/BluetoothAvrcpController.java b/core/java/android/bluetooth/BluetoothAvrcpController.java
index 536dfb0..81fc3e1 100644
--- a/core/java/android/bluetooth/BluetoothAvrcpController.java
+++ b/core/java/android/bluetooth/BluetoothAvrcpController.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.annotation.RequiresPermission;
 import android.annotation.SdkConstant;
 import android.annotation.SdkConstant.SdkConstantType;
@@ -23,13 +25,15 @@
 import android.bluetooth.annotations.RequiresLegacyBluetoothPermission;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the public APIs to control the Bluetooth AVRCP Controller. It currently
@@ -93,8 +97,7 @@
                     "BluetoothAvrcpController", IBluetoothAvrcpController.class.getName()) {
                 @Override
                 public IBluetoothAvrcpController getServiceInterface(IBinder service) {
-                    return IBluetoothAvrcpController.Stub.asInterface(
-                            Binder.allowBlocking(service));
+                    return IBluetoothAvrcpController.Stub.asInterface(service);
                 }
     };
 
@@ -130,19 +133,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothDevice> getConnectedDevices() {
         if (VDBG) log("getConnectedDevices()");
-        final IBluetoothAvrcpController service =
-                getService();
-        if (service != null && isEnabled()) {
+        final IBluetoothAvrcpController service = getService();
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -153,20 +161,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (VDBG) log("getDevicesMatchingStates()");
-        final IBluetoothAvrcpController service =
-                getService();
-        if (service != null && isEnabled()) {
+        final IBluetoothAvrcpController service = getService();
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -177,18 +189,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public int getConnectionState(BluetoothDevice device) {
         if (VDBG) log("getState(" + device + ")");
-        final IBluetoothAvrcpController service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothAvrcpController service = getService();
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -201,17 +216,22 @@
     public BluetoothAvrcpPlayerSettings getPlayerSettings(BluetoothDevice device) {
         if (DBG) Log.d(TAG, "getPlayerSettings");
         BluetoothAvrcpPlayerSettings settings = null;
-        final IBluetoothAvrcpController service =
-                getService();
-        if (service != null && isEnabled()) {
+        final IBluetoothAvrcpController service = getService();
+        final BluetoothAvrcpPlayerSettings defaultValue = null;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
-                settings = service.getPlayerSettings(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Error talking to BT service in getMetadata() " + e);
-                return null;
+                final SynchronousResultReceiver<BluetoothAvrcpPlayerSettings> recv =
+                        new SynchronousResultReceiver();
+                service.getPlayerSettings(device, mAttributionSource, recv);
+                settings = recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        return settings;
+        return defaultValue;
     }
 
     /**
@@ -222,18 +242,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean setPlayerApplicationSetting(BluetoothAvrcpPlayerSettings plAppSetting) {
         if (DBG) Log.d(TAG, "setPlayerApplicationSetting");
-        final IBluetoothAvrcpController service =
-                getService();
-        if (service != null && isEnabled()) {
+        final IBluetoothAvrcpController service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
-                return service.setPlayerApplicationSetting(plAppSetting, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Error talking to BT service in setPlayerApplicationSetting() " + e);
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setPlayerApplicationSetting(plAppSetting, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -245,18 +268,20 @@
     public void sendGroupNavigationCmd(BluetoothDevice device, int keyCode, int keyState) {
         Log.d(TAG, "sendGroupNavigationCmd dev = " + device + " key " + keyCode + " State = "
                 + keyState);
-        final IBluetoothAvrcpController service =
-                getService();
-        if (service != null && isEnabled()) {
+        final IBluetoothAvrcpController service = getService();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
-                service.sendGroupNavigationCmd(device, keyCode, keyState, mAttributionSource);
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.sendGroupNavigationCmd(device, keyCode, keyState, mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
                 return;
-            } catch (RemoteException e) {
-                Log.e(TAG, "Error talking to BT service in sendGroupNavigationCmd()", e);
-                return;
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
     }
 
     private boolean isEnabled() {
diff --git a/core/java/android/bluetooth/BluetoothCsipSetCoordinator.java b/core/java/android/bluetooth/BluetoothCsipSetCoordinator.java
index f0a8df0..ba57ec4 100644
--- a/core/java/android/bluetooth/BluetoothCsipSetCoordinator.java
+++ b/core/java/android/bluetooth/BluetoothCsipSetCoordinator.java
@@ -17,6 +17,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.CallbackExecutor;
 import android.annotation.NonNull;
@@ -27,13 +29,14 @@
 import android.annotation.SystemApi;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.IBinder;
 import android.os.ParcelUuid;
 import android.os.RemoteException;
 import android.util.CloseGuard;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -41,6 +44,7 @@
 import java.util.Map;
 import java.util.UUID;
 import java.util.concurrent.Executor;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the public APIs to control the Bluetooth CSIP set coordinator.
@@ -229,8 +233,7 @@
                     IBluetoothCsipSetCoordinator.class.getName()) {
                 @Override
                 public IBluetoothCsipSetCoordinator getServiceInterface(IBinder service) {
-                    return IBluetoothCsipSetCoordinator.Stub.asInterface(
-                            Binder.allowBlocking(service));
+                    return IBluetoothCsipSetCoordinator.Stub.asInterface(service);
                 }
             };
 
@@ -283,26 +286,27 @@
     public
     @Nullable UUID groupLock(int groupId, @Nullable @CallbackExecutor Executor executor,
             @Nullable ClientLockCallback cb) {
-        if (VDBG) {
-            log("groupLockSet()");
-        }
+        if (VDBG) log("groupLockSet()");
         final IBluetoothCsipSetCoordinator service = getService();
-        try {
-            if (service != null && isEnabled()) {
-                IBluetoothCsipSetCoordinatorLockCallback delegate = null;
-                if ((executor != null) && (cb != null)) {
-                    delegate = new BluetoothCsipSetCoordinatorLockCallbackDelegate(executor, cb);
-                }
-                return service.groupLock(groupId, delegate, mAttributionSource).getUuid();
+        final UUID defaultValue = null;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            IBluetoothCsipSetCoordinatorLockCallback delegate = null;
+            if ((executor != null) && (cb != null)) {
+                delegate = new BluetoothCsipSetCoordinatorLockCallbackDelegate(executor, cb);
             }
-            if (service == null) {
-                Log.w(TAG, "Proxy not attached to service");
+            try {
+                final SynchronousResultReceiver<ParcelUuid> recv = new SynchronousResultReceiver();
+                service.groupLock(groupId, delegate, mAttributionSource, recv);
+                final ParcelUuid ret = recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
+                return ret == null ? defaultValue : ret.getUuid();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            return null;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return null;
         }
+        return defaultValue;
     }
 
     /**
@@ -315,27 +319,26 @@
     @SystemApi
     @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
     public boolean groupUnlock(@NonNull UUID lockUuid) {
-        if (VDBG) {
-            log("groupLockSet()");
-        }
+        if (VDBG) log("groupLockSet()");
         if (lockUuid == null) {
             return false;
         }
-
         final IBluetoothCsipSetCoordinator service = getService();
-        try {
-            if (service != null && isEnabled()) {
-                service.groupUnlock(new ParcelUuid(lockUuid), mAttributionSource);
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.groupUnlock(new ParcelUuid(lockUuid), mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
                 return true;
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) {
-                Log.w(TAG, "Proxy not attached to service");
-            }
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -348,22 +351,22 @@
     @SystemApi
     @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
     public @NonNull Map getGroupUuidMapByDevice(@Nullable BluetoothDevice device) {
-        if (VDBG) {
-            log("getGroupUuidMapByDevice()");
-        }
+        if (VDBG) log("getGroupUuidMapByDevice()");
         final IBluetoothCsipSetCoordinator service = getService();
-        try {
-            if (service != null && isEnabled()) {
-                return service.getGroupUuidMapByDevice(device, mAttributionSource);
+        final Map defaultValue = new HashMap<>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Map> recv = new SynchronousResultReceiver();
+                service.getGroupUuidMapByDevice(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) {
-                Log.w(TAG, "Proxy not attached to service");
-            }
-            return new HashMap<>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new HashMap<>();
         }
+        return defaultValue;
     }
 
     /**
@@ -376,22 +379,23 @@
     @SystemApi
     @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
     public @NonNull List<Integer> getAllGroupIds(@Nullable ParcelUuid uuid) {
-        if (VDBG) {
-            log("getAllGroupIds()");
-        }
+        if (VDBG) log("getAllGroupIds()");
         final IBluetoothCsipSetCoordinator service = getService();
-        try {
-            if (service != null && isEnabled()) {
-                return service.getAllGroupIds(uuid, mAttributionSource);
+        final List<Integer> defaultValue = new ArrayList<>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<Integer>> recv =
+                        new SynchronousResultReceiver();
+                service.getAllGroupIds(uuid, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) {
-                Log.w(TAG, "Proxy not attached to service");
-            }
-            return new ArrayList<Integer>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new ArrayList<Integer>();
         }
+        return defaultValue;
     }
 
     /**
@@ -399,22 +403,23 @@
      */
     @Override
     public @NonNull List<BluetoothDevice> getConnectedDevices() {
-        if (VDBG) {
-            log("getConnectedDevices()");
-        }
+        if (VDBG) log("getConnectedDevices()");
         final IBluetoothCsipSetCoordinator service = getService();
-        if (service != null && isEnabled()) {
-            try {
-                return service.getConnectedDevices(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
-            }
-        }
+        final List<BluetoothDevice> defaultValue = new ArrayList<>();
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -422,24 +427,24 @@
      */
     @Override
     public
-    @NonNull List<BluetoothDevice> getDevicesMatchingConnectionStates(
-            @NonNull int[] states) {
-        if (VDBG) {
-            log("getDevicesMatchingStates(states=" + Arrays.toString(states) + ")");
-        }
+    @NonNull List<BluetoothDevice> getDevicesMatchingConnectionStates(@NonNull int[] states) {
+        if (VDBG) log("getDevicesMatchingStates(states=" + Arrays.toString(states) + ")");
         final IBluetoothCsipSetCoordinator service = getService();
-        if (service != null && isEnabled()) {
-            try {
-                return service.getDevicesMatchingConnectionStates(states, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
-            }
-        }
+        final List<BluetoothDevice> defaultValue = new ArrayList<>();
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -447,24 +452,23 @@
      */
     @Override
     public
-    @BluetoothProfile.BtProfileState int getConnectionState(
-            @Nullable BluetoothDevice device) {
-        if (VDBG) {
-            log("getState(" + device + ")");
-        }
+    @BluetoothProfile.BtProfileState int getConnectionState(@Nullable BluetoothDevice device) {
+        if (VDBG) log("getState(" + device + ")");
         final IBluetoothCsipSetCoordinator service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
-            }
-        }
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -484,26 +488,24 @@
     @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
     public boolean setConnectionPolicy(
             @Nullable BluetoothDevice device, @ConnectionPolicy int connectionPolicy) {
-        if (DBG) {
-            log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
-        }
+        if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
         final IBluetoothCsipSetCoordinator service = getService();
-        try {
-            if (service != null && isEnabled() && isValidDevice(device)) {
-                if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                        && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                    return false;
-                }
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) {
-                Log.w(TAG, "Proxy not attached to service");
-            }
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -521,22 +523,22 @@
     @SystemApi
     @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
     public @ConnectionPolicy int getConnectionPolicy(@Nullable BluetoothDevice device) {
-        if (VDBG) {
-            log("getConnectionPolicy(" + device + ")");
-        }
+        if (VDBG) log("getConnectionPolicy(" + device + ")");
         final IBluetoothCsipSetCoordinator service = getService();
-        try {
-            if (service != null && isEnabled() && isValidDevice(device)) {
-                return service.getConnectionPolicy(device, mAttributionSource);
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) {
-                Log.w(TAG, "Proxy not attached to service");
-            }
-            return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
         }
+        return defaultValue;
     }
 
     private boolean isEnabled() {
diff --git a/core/java/android/bluetooth/BluetoothHeadset.java b/core/java/android/bluetooth/BluetoothHeadset.java
index 17c02cd..f2a6276 100644
--- a/core/java/android/bluetooth/BluetoothHeadset.java
+++ b/core/java/android/bluetooth/BluetoothHeadset.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.RequiresPermission;
@@ -31,7 +33,6 @@
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.pm.PackageManager;
-import android.os.Binder;
 import android.os.Build;
 import android.os.Handler;
 import android.os.IBinder;
@@ -41,8 +42,11 @@
 import android.util.CloseGuard;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * Public API for controlling the Bluetooth Headset Service. This includes both
@@ -479,16 +483,20 @@
     public boolean connect(BluetoothDevice device) {
         if (DBG) log("connect(" + device + ")");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.connect(device);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connectWithAttribution(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -520,16 +528,20 @@
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.disconnect(device);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnectWithAttribution(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -541,18 +553,23 @@
     public List<BluetoothDevice> getConnectedDevices() {
         if (VDBG) log("getConnectedDevices()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevicesWithAttribution(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevicesWithAttribution(mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -564,18 +581,23 @@
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (VDBG) log("getDevicesMatchingStates()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -587,16 +609,20 @@
     public int getConnectionState(BluetoothDevice device) {
         if (VDBG) log("getConnectionState(" + device + ")");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionStateWithAttribution(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -622,20 +648,22 @@
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                    && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                return false;
-            }
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
             try {
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -655,18 +683,7 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public int getPriority(BluetoothDevice device) {
         if (VDBG) log("getPriority(" + device + ")");
-        final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            try {
-                return BluetoothAdapter.connectionPolicyToPriority(
-                        service.getPriority(device, mAttributionSource));
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.PRIORITY_OFF;
-            }
-        }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.PRIORITY_OFF;
+        return BluetoothAdapter.connectionPolicyToPriority(getConnectionPolicy(device));
     }
 
     /**
@@ -689,16 +706,20 @@
     public @ConnectionPolicy int getConnectionPolicy(@NonNull BluetoothDevice device) {
         if (VDBG) log("getConnectionPolicy(" + device + ")");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionPolicy(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        return defaultValue;
     }
 
     /**
@@ -713,15 +734,20 @@
     public boolean isNoiseReductionSupported(@NonNull BluetoothDevice device) {
         if (DBG) log("isNoiseReductionSupported()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.isNoiseReductionSupported(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isNoiseReductionSupported(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -736,15 +762,20 @@
     public boolean isVoiceRecognitionSupported(@NonNull BluetoothDevice device) {
         if (DBG) log("isVoiceRecognitionSupported()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.isVoiceRecognitionSupported(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isVoiceRecognitionSupported(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -775,15 +806,20 @@
     public boolean startVoiceRecognition(BluetoothDevice device) {
         if (DBG) log("startVoiceRecognition()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.startVoiceRecognition(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.startVoiceRecognition(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -804,15 +840,20 @@
     public boolean stopVoiceRecognition(BluetoothDevice device) {
         if (DBG) log("stopVoiceRecognition()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.stopVoiceRecognition(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.stopVoiceRecognition(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -827,15 +868,20 @@
     public boolean isAudioConnected(BluetoothDevice device) {
         if (VDBG) log("isAudioConnected()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.isAudioConnected(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isAudioConnected(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -861,17 +907,20 @@
     public int getAudioState(BluetoothDevice device) {
         if (VDBG) log("getAudioState");
         final IBluetoothHeadset service = mService;
-        if (service != null && !isDisabled()) {
-            try {
-                return service.getAudioState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final int defaultValue = BluetoothHeadset.STATE_AUDIO_DISCONNECTED;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (!isDisabled()) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getAudioState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return BluetoothHeadset.STATE_AUDIO_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -889,15 +938,17 @@
     public void setAudioRouteAllowed(boolean allowed) {
         if (VDBG) log("setAudioRouteAllowed");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                service.setAudioRouteAllowed(allowed, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.setAudioRouteAllowed(allowed, mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
     }
 
@@ -912,17 +963,20 @@
     public boolean getAudioRouteAllowed() {
         if (VDBG) log("getAudioRouteAllowed");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                return service.getAudioRouteAllowed(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.getAudioRouteAllowed(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -937,15 +991,17 @@
     public void setForceScoAudio(boolean forced) {
         if (VDBG) log("setForceScoAudio " + String.valueOf(forced));
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                service.setForceScoAudio(forced, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.setForceScoAudio(forced, mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
     }
 
@@ -962,16 +1018,20 @@
     public boolean isAudioOn() {
         if (VDBG) log("isAudioOn()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
-                return service.isAudioOn(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isAudioOn(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
-
+        return defaultValue;
     }
 
     /**
@@ -996,18 +1056,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean connectAudio() {
+        if (VDBG) log("connectAudio()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                return service.connectAudio(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connectAudio(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1025,18 +1089,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean disconnectAudio() {
+        if (VDBG) log("disconnectAudio()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                return service.disconnectAudio(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnectAudio(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1070,17 +1138,20 @@
     public boolean startScoUsingVirtualVoiceCall() {
         if (DBG) log("startScoUsingVirtualVoiceCall()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                return service.startScoUsingVirtualVoiceCall(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.startScoUsingVirtualVoiceCall(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1105,17 +1176,20 @@
     public boolean stopScoUsingVirtualVoiceCall() {
         if (DBG) log("stopScoUsingVirtualVoiceCall()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                return service.stopScoUsingVirtualVoiceCall(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.stopScoUsingVirtualVoiceCall(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1135,16 +1209,16 @@
     public void phoneStateChanged(int numActive, int numHeld, int callState, String number,
             int type, String name) {
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
                 service.phoneStateChanged(numActive, numHeld, callState, number, type, name,
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
+            } catch (RemoteException  e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-        } else {
-            Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
         }
     }
 
@@ -1161,16 +1235,18 @@
     public void clccResponse(int index, int direction, int status, int mode, boolean mpty,
             String number, int type) {
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                service.clccResponse(index, direction, status, mode, mpty, number, type,
-                        mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.clccResponse(index, direction, status, mode, mpty, number, type,
+                        mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
     }
 
@@ -1202,18 +1278,21 @@
             throw new IllegalArgumentException("command is null");
         }
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            try {
-                return service.sendVendorSpecificResultCode(device, command, arg,
-                        mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-            }
-        }
+        final boolean defaultValue = false;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.sendVendorSpecificResultCode(device, command, arg,
+                        mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1247,17 +1326,20 @@
             Log.d(TAG, "setActiveDevice: " + device);
         }
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled() && (device == null || isValidDevice(device))) {
-            try {
-                return service.setActiveDevice(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-            }
-        }
+        final boolean defaultValue = false;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && (device == null || isValidDevice(device))) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setActiveDevice(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1273,22 +1355,25 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public BluetoothDevice getActiveDevice() {
-        if (VDBG) {
-            Log.d(TAG, "getActiveDevice");
-        }
+        if (VDBG) Log.d(TAG, "getActiveDevice");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                return Attributable.setAttributionSource(
-                        service.getActiveDevice(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-            }
-        }
+        final BluetoothDevice defaultValue = null;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<BluetoothDevice> recv =
+                        new SynchronousResultReceiver();
+                service.getActiveDevice(mAttributionSource, recv);
+                return Attributable.setAttributionSource(
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return null;
+        return defaultValue;
     }
 
     /**
@@ -1303,21 +1388,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_PRIVILEGED)
     public boolean isInbandRingingEnabled() {
-        if (DBG) {
-            log("isInbandRingingEnabled()");
-        }
+        if (DBG) log("isInbandRingingEnabled()");
         final IBluetoothHeadset service = mService;
-        if (service != null && isEnabled()) {
-            try {
-                return service.isInbandRingingEnabled(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-            }
-        }
+        final boolean defaultValue = false;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isInbandRingingEnabled(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1337,7 +1423,7 @@
         @Override
         public void onServiceConnected(ComponentName className, IBinder service) {
             if (DBG) Log.d(TAG, "Proxy object connected");
-            mService = IBluetoothHeadset.Stub.asInterface(Binder.allowBlocking(service));
+            mService = IBluetoothHeadset.Stub.asInterface(service);
             mHandler.sendMessage(mHandler.obtainMessage(
                     MESSAGE_HEADSET_SERVICE_CONNECTED));
         }
diff --git a/core/java/android/bluetooth/BluetoothHeadsetClient.java b/core/java/android/bluetooth/BluetoothHeadsetClient.java
index 2ef3710..7d7a7f7 100644
--- a/core/java/android/bluetooth/BluetoothHeadsetClient.java
+++ b/core/java/android/bluetooth/BluetoothHeadsetClient.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.annotation.NonNull;
 import android.annotation.RequiresPermission;
 import android.annotation.SdkConstant;
@@ -25,15 +27,17 @@
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * Public API to control Hands Free Profile (HFP role only).
@@ -432,7 +436,7 @@
                     "BluetoothHeadsetClient", IBluetoothHeadsetClient.class.getName()) {
                 @Override
                 public IBluetoothHeadsetClient getServiceInterface(IBinder service) {
-                    return IBluetoothHeadsetClient.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothHeadsetClient.Stub.asInterface(service);
                 }
     };
 
@@ -479,18 +483,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean connect(BluetoothDevice device) {
         if (DBG) log("connect(" + device + ")");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.connect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -507,18 +514,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.disconnect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -531,19 +541,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothDevice> getConnectedDevices() {
         if (VDBG) log("getConnectedDevices()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled()) {
+        final IBluetoothHeadsetClient service = getService();
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -558,20 +573,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (VDBG) log("getDevicesMatchingStates()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled()) {
+        final IBluetoothHeadsetClient service = getService();
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -585,18 +604,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public int getConnectionState(BluetoothDevice device) {
         if (VDBG) log("getConnectionState(" + device + ")");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -634,22 +656,23 @@
     public boolean setConnectionPolicy(@NonNull BluetoothDevice device,
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                    && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                return false;
-            }
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
             try {
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -686,18 +709,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public @ConnectionPolicy int getConnectionPolicy(@NonNull BluetoothDevice device) {
         if (VDBG) log("getConnectionPolicy(" + device + ")");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final @ConnectionPolicy int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionPolicy(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        return defaultValue;
     }
 
     /**
@@ -715,17 +741,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean startVoiceRecognition(BluetoothDevice device) {
         if (DBG) log("startVoiceRecognition()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.startVoiceRecognition(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.startVoiceRecognition(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -739,20 +769,23 @@
      */
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
-    public boolean sendVendorAtCommand(BluetoothDevice device, int vendorId,
-                                             String atCommand) {
+    public boolean sendVendorAtCommand(BluetoothDevice device, int vendorId, String atCommand) {
         if (DBG) log("sendVendorSpecificCommand()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.sendVendorAtCommand(device, vendorId, atCommand, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.sendVendorAtCommand(device, vendorId, atCommand, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -770,17 +803,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean stopVoiceRecognition(BluetoothDevice device) {
         if (DBG) log("stopVoiceRecognition()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.stopVoiceRecognition(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.stopVoiceRecognition(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -793,18 +830,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothHeadsetClientCall> getCurrentCalls(BluetoothDevice device) {
         if (DBG) log("getCurrentCalls()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final List<BluetoothHeadsetClientCall> defaultValue = null;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
+                final SynchronousResultReceiver<List<BluetoothHeadsetClientCall>> recv =
+                        new SynchronousResultReceiver();
+                service.getCurrentCalls(device, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getCurrentCalls(device, mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return null;
+        return defaultValue;
     }
 
     /**
@@ -817,17 +860,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public Bundle getCurrentAgEvents(BluetoothDevice device) {
         if (DBG) log("getCurrentAgEvents()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final Bundle defaultValue = null;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getCurrentAgEvents(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Bundle> recv = new SynchronousResultReceiver();
+                service.getCurrentAgEvents(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return null;
+        return defaultValue;
     }
 
     /**
@@ -844,17 +891,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean acceptCall(BluetoothDevice device, int flag) {
         if (DBG) log("acceptCall()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.acceptCall(device, flag, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.acceptCall(device, flag, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -868,17 +919,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean holdCall(BluetoothDevice device) {
         if (DBG) log("holdCall()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.holdCall(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.holdCall(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -897,17 +952,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean rejectCall(BluetoothDevice device) {
         if (DBG) log("rejectCall()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.rejectCall(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.rejectCall(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -930,17 +989,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean terminateCall(BluetoothDevice device, BluetoothHeadsetClientCall call) {
         if (DBG) log("terminateCall()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.terminateCall(device, call, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.terminateCall(device, call, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -961,17 +1024,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean enterPrivateMode(BluetoothDevice device, int index) {
         if (DBG) log("enterPrivateMode()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.enterPrivateMode(device, index, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.enterPrivateMode(device, index, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -991,17 +1058,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean explicitCallTransfer(BluetoothDevice device) {
         if (DBG) log("explicitCallTransfer()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.explicitCallTransfer(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.explicitCallTransfer(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1017,18 +1088,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public BluetoothHeadsetClientCall dial(BluetoothDevice device, String number) {
         if (DBG) log("dial()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final BluetoothHeadsetClientCall defaultValue = null;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
+                final SynchronousResultReceiver<BluetoothHeadsetClientCall> recv =
+                        new SynchronousResultReceiver();
+                service.dial(device, number, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.dial(device, number, mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return null;
+        return defaultValue;
     }
 
     /**
@@ -1045,17 +1122,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean sendDTMF(BluetoothDevice device, byte code) {
         if (DBG) log("sendDTMF()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.sendDTMF(device, code, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.sendDTMF(device, code, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1074,17 +1155,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean getLastVoiceTagNumber(BluetoothDevice device) {
         if (DBG) log("getLastVoiceTagNumber()");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getLastVoiceTagNumber(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.getLastVoiceTagNumber(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1097,17 +1182,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public int getAudioState(BluetoothDevice device) {
         if (VDBG) log("getAudioState");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled()) {
+        final IBluetoothHeadsetClient service = getService();
+        final int defaultValue = BluetoothHeadsetClient.STATE_AUDIO_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
-                return service.getAudioState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getAudioState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         } else {
-            Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            return defaultValue;
         }
         return BluetoothHeadsetClient.STATE_AUDIO_DISCONNECTED;
     }
@@ -1123,17 +1212,18 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public void setAudioRouteAllowed(BluetoothDevice device, boolean allowed) {
         if (VDBG) log("setAudioRouteAllowed");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled()) {
-            try {
-                service.setAudioRouteAllowed(device, allowed, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final IBluetoothHeadsetClient service = getService();
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.setAudioRouteAllowed(device, allowed, mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
     }
 
@@ -1148,19 +1238,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean getAudioRouteAllowed(BluetoothDevice device) {
         if (VDBG) log("getAudioRouteAllowed");
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled()) {
-            try {
-                return service.getAudioRouteAllowed(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.getAudioRouteAllowed(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1175,19 +1267,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean connectAudio(BluetoothDevice device) {
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled()) {
-            try {
-                return service.connectAudio(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        if (VDBG) log("connectAudio");
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connectAudio(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1202,19 +1297,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean disconnectAudio(BluetoothDevice device) {
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled()) {
-            try {
-                return service.disconnectAudio(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        if (VDBG) log("disconnectAudio");
+        final IBluetoothHeadsetClient service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnectAudio(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -1226,19 +1324,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public Bundle getCurrentAgFeatures(BluetoothDevice device) {
-        final IBluetoothHeadsetClient service =
-                getService();
-        if (service != null && isEnabled()) {
-            try {
-                return service.getCurrentAgFeatures(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        if (VDBG) log("getCurrentAgFeatures");
+        final IBluetoothHeadsetClient service = getService();
+        final Bundle defaultValue = null;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
-            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Bundle> recv = new SynchronousResultReceiver();
+                service.getCurrentAgFeatures(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return null;
+        return defaultValue;
     }
 
     private boolean isEnabled() {
diff --git a/core/java/android/bluetooth/BluetoothHearingAid.java b/core/java/android/bluetooth/BluetoothHearingAid.java
index a00b20d..339a75f 100644
--- a/core/java/android/bluetooth/BluetoothHearingAid.java
+++ b/core/java/android/bluetooth/BluetoothHearingAid.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.RequiresPermission;
@@ -28,14 +30,16 @@
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.Build;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the public APIs to control the Hearing Aid profile.
@@ -136,7 +140,7 @@
                     "BluetoothHearingAid", IBluetoothHearingAid.class.getName()) {
                 @Override
                 public IBluetoothHearingAid getServiceInterface(IBinder service) {
-                    return IBluetoothHearingAid.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothHearingAid.Stub.asInterface(service);
                 }
     };
 
@@ -181,16 +185,20 @@
     public boolean connect(BluetoothDevice device) {
         if (DBG) log("connect(" + device + ")");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled() && isValidDevice(device)) {
-                return service.connect(device, mAttributionSource);
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -223,16 +231,20 @@
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled() && isValidDevice(device)) {
-                return service.disconnect(device, mAttributionSource);
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -244,17 +256,23 @@
     public @NonNull List<BluetoothDevice> getConnectedDevices() {
         if (VDBG) log("getConnectedDevices()");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return new ArrayList<BluetoothDevice>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new ArrayList<BluetoothDevice>();
         }
+        return defaultValue;
     }
 
     /**
@@ -267,18 +285,23 @@
     @NonNull int[] states) {
         if (VDBG) log("getDevicesMatchingStates()");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return new ArrayList<BluetoothDevice>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new ArrayList<BluetoothDevice>();
         }
+        return defaultValue;
     }
 
     /**
@@ -291,17 +314,20 @@
     @NonNull BluetoothDevice device) {
         if (VDBG) log("getState(" + device + ")");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                return service.getConnectionState(device, mAttributionSource);
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return BluetoothProfile.STATE_DISCONNECTED;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return BluetoothProfile.STATE_DISCONNECTED;
         }
+        return defaultValue;
     }
 
     /**
@@ -330,18 +356,20 @@
     public boolean setActiveDevice(@Nullable BluetoothDevice device) {
         if (DBG) log("setActiveDevice(" + device + ")");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled()
-                    && ((device == null) || isValidDevice(device))) {
-                service.setActiveDevice(device, mAttributionSource);
-                return true;
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && ((device == null) || isValidDevice(device))) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setActiveDevice(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -359,17 +387,23 @@
     public @NonNull List<BluetoothDevice> getActiveDevices() {
         if (VDBG) log("getActiveDevices()");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getActiveDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getActiveDevices(mAttributionSource), mAttributionSource);
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return new ArrayList<>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new ArrayList<>();
         }
+        return defaultValue;
     }
 
     /**
@@ -416,21 +450,22 @@
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
         verifyDeviceNotNull(device, "setConnectionPolicy");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                        && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                    return false;
-                }
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                    && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                        || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -474,17 +509,20 @@
         if (VDBG) log("getConnectionPolicy(" + device + ")");
         verifyDeviceNotNull(device, "getConnectionPolicy");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                return service.getConnectionPolicy(device, mAttributionSource);
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
         }
+        return defaultValue;
     }
 
     /**
@@ -519,19 +557,18 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public void setVolume(int volume) {
         if (DBG) Log.d(TAG, "setVolume(" + volume + ")");
-
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service == null) {
-                Log.w(TAG, "Proxy not attached to service");
-                return;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.setVolume(volume, mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-
-            if (!isEnabled()) return;
-
-            service.setVolume(volume, mAttributionSource);
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
         }
     }
 
@@ -552,24 +589,23 @@
             android.Manifest.permission.BLUETOOTH_PRIVILEGED,
     })
     public long getHiSyncId(@NonNull BluetoothDevice device) {
-        if (VDBG) {
-            log("getHiSyncId(" + device + ")");
-        }
+        if (VDBG) log("getHiSyncId(" + device + ")");
         verifyDeviceNotNull(device, "getConnectionPolicy");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service == null) {
-                Log.w(TAG, "Proxy not attached to service");
-                return HI_SYNC_ID_INVALID;
+        final long defaultValue = HI_SYNC_ID_INVALID;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Long> recv = new SynchronousResultReceiver();
+                service.getHiSyncId(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-
-            if (!isEnabled() || !isValidDevice(device)) return HI_SYNC_ID_INVALID;
-
-            return service.getHiSyncId(device, mAttributionSource);
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return HI_SYNC_ID_INVALID;
         }
+        return defaultValue;
     }
 
     /**
@@ -583,21 +619,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public int getDeviceSide(BluetoothDevice device) {
-        if (VDBG) {
-            log("getDeviceSide(" + device + ")");
-        }
+        if (VDBG) log("getDeviceSide(" + device + ")");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                return service.getDeviceSide(device, mAttributionSource);
+        final int defaultValue = SIDE_LEFT;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getDeviceSide(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return SIDE_LEFT;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return SIDE_LEFT;
         }
+        return defaultValue;
     }
 
     /**
@@ -611,21 +648,22 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public int getDeviceMode(BluetoothDevice device) {
-        if (VDBG) {
-            log("getDeviceMode(" + device + ")");
-        }
+        if (VDBG) log("getDeviceMode(" + device + ")");
         final IBluetoothHearingAid service = getService();
-        try {
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                return service.getDeviceMode(device, mAttributionSource);
+        final int defaultValue = MODE_MONAURAL;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getDeviceMode(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return MODE_MONAURAL;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return MODE_MONAURAL;
         }
+        return defaultValue;
     }
 
     private boolean isEnabled() {
diff --git a/core/java/android/bluetooth/BluetoothHidDevice.java b/core/java/android/bluetooth/BluetoothHidDevice.java
index f5b444f..44a355b 100644
--- a/core/java/android/bluetooth/BluetoothHidDevice.java
+++ b/core/java/android/bluetooth/BluetoothHidDevice.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.NonNull;
 import android.annotation.RequiresPermission;
@@ -26,14 +28,16 @@
 import android.bluetooth.annotations.RequiresLegacyBluetoothPermission;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Executor;
+import java.util.concurrent.TimeoutException;
 
 /**
  * Provides the public APIs to control the Bluetooth HID Device profile.
@@ -431,7 +435,7 @@
                     "BluetoothHidDevice", IBluetoothHidDevice.class.getName()) {
                 @Override
                 public IBluetoothHidDevice getServiceInterface(IBinder service) {
-                    return IBluetoothHidDevice.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothHidDevice.Stub.asInterface(service);
                 }
     };
 
@@ -455,18 +459,23 @@
     @RequiresPermission(Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothDevice> getConnectedDevices() {
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final List<BluetoothDevice> defaultValue = new ArrayList<>();
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
+                return Attributable.setAttributionSource(
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return new ArrayList<>();
+        return defaultValue;
     }
 
     /** {@inheritDoc} */
@@ -475,19 +484,23 @@
     @RequiresPermission(Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
-                        mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final List<BluetoothDevice> defaultValue = new ArrayList<>();
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
+                return Attributable.setAttributionSource(
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return new ArrayList<>();
+        return defaultValue;
     }
 
     /** {@inheritDoc} */
@@ -496,17 +509,20 @@
     @RequiresPermission(Manifest.permission.BLUETOOTH_CONNECT)
     public int getConnectionState(BluetoothDevice device) {
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final int defaultValue = STATE_DISCONNECTED;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -555,18 +571,21 @@
         }
 
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                CallbackWrapper cbw = new CallbackWrapper(executor, callback, mAttributionSource);
-                result = service.registerApp(sdp, inQos, outQos, cbw, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = result;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                CallbackWrapper cbw = new CallbackWrapper(executor, callback, mAttributionSource);
+                service.registerApp(sdp, inQos, outQos, cbw, mAttributionSource, recv);
+                result = recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return result;
+        return defaultValue;
     }
 
     /**
@@ -582,20 +601,21 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean unregisterApp() {
-        boolean result = false;
-
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                result = service.unregisterApp(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.unregisterApp(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return result;
+        return defaultValue;
     }
 
     /**
@@ -609,20 +629,21 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean sendReport(BluetoothDevice device, int id, byte[] data) {
-        boolean result = false;
-
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                result = service.sendReport(device, id, data, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.sendReport(device, id, data, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return result;
+        return defaultValue;
     }
 
     /**
@@ -637,20 +658,21 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean replyReport(BluetoothDevice device, byte type, byte id, byte[] data) {
-        boolean result = false;
-
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                result = service.replyReport(device, type, id, data, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.replyReport(device, type, id, data, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return result;
+        return defaultValue;
     }
 
     /**
@@ -663,20 +685,21 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean reportError(BluetoothDevice device, byte error) {
-        boolean result = false;
-
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                result = service.reportError(device, error, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.reportError(device, error, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return result;
+        return defaultValue;
     }
 
     /**
@@ -689,18 +712,20 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public String getUserAppName() {
         final IBluetoothHidDevice service = getService();
-
-        if (service != null) {
-            try {
-                return service.getUserAppName(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final String defaultValue = "";
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<String> recv = new SynchronousResultReceiver();
+                service.getUserAppName(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return "";
+        return defaultValue;
     }
 
     /**
@@ -714,20 +739,21 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean connect(BluetoothDevice device) {
-        boolean result = false;
-
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                result = service.connect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return result;
+        return defaultValue;
     }
 
     /**
@@ -740,20 +766,21 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean disconnect(BluetoothDevice device) {
-        boolean result = false;
-
         final IBluetoothHidDevice service = getService();
-        if (service != null) {
-            try {
-                result = service.disconnect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-
-        return result;
+        return defaultValue;
     }
 
     /**
@@ -781,23 +808,24 @@
     })
     public boolean setConnectionPolicy(@NonNull BluetoothDevice device,
             @ConnectionPolicy int connectionPolicy) {
-        log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
-        try {
-            final IBluetoothHidDevice service = getService();
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                        && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                    return false;
-                }
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
+        if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
+        final IBluetoothHidDevice service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     private boolean isEnabled() {
diff --git a/core/java/android/bluetooth/BluetoothHidHost.java b/core/java/android/bluetooth/BluetoothHidHost.java
index 121aa16..ecbeddf 100644
--- a/core/java/android/bluetooth/BluetoothHidHost.java
+++ b/core/java/android/bluetooth/BluetoothHidHost.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.NonNull;
 import android.annotation.RequiresPermission;
@@ -28,13 +30,15 @@
 import android.bluetooth.annotations.RequiresLegacyBluetoothPermission;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 
 /**
@@ -244,7 +248,7 @@
                     "BluetoothHidHost", IBluetoothHidHost.class.getName()) {
                 @Override
                 public IBluetoothHidHost getServiceInterface(IBinder service) {
-                    return IBluetoothHidHost.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothHidHost.Stub.asInterface(service);
                 }
     };
 
@@ -292,16 +296,20 @@
     public boolean connect(BluetoothDevice device) {
         if (DBG) log("connect(" + device + ")");
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.connect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -334,16 +342,20 @@
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.disconnect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -358,17 +370,23 @@
     public @NonNull List<BluetoothDevice> getConnectedDevices() {
         if (VDBG) log("getConnectedDevices()");
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -382,18 +400,23 @@
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (VDBG) log("getDevicesMatchingStates()");
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -411,16 +434,20 @@
             throw new IllegalArgumentException("device must not be null");
         }
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -469,20 +496,22 @@
             throw new IllegalArgumentException("device must not be null");
         }
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                    && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                return false;
-            }
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
             try {
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -528,16 +557,20 @@
             throw new IllegalArgumentException("device must not be null");
         }
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionPolicy(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        return defaultValue;
     }
 
     private boolean isEnabled() {
@@ -561,18 +594,20 @@
     public boolean virtualUnplug(BluetoothDevice device) {
         if (DBG) log("virtualUnplug(" + device + ")");
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.virtualUnplug(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.virtualUnplug(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
-
+        return defaultValue;
     }
 
     /**
@@ -588,16 +623,20 @@
     public boolean getProtocolMode(BluetoothDevice device) {
         if (VDBG) log("getProtocolMode(" + device + ")");
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getProtocolMode(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.getProtocolMode(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -613,16 +652,20 @@
     public boolean setProtocolMode(BluetoothDevice device, int protocolMode) {
         if (DBG) log("setProtocolMode(" + device + ")");
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.setProtocolMode(device, protocolMode, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setProtocolMode(device, protocolMode, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -645,17 +688,21 @@
                     + "bufferSize=" + bufferSize);
         }
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getReport(device, reportType, reportId, bufferSize,
-                        mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.getReport(device, reportType, reportId, bufferSize, mAttributionSource,
+                        recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -673,16 +720,20 @@
     public boolean setReport(BluetoothDevice device, byte reportType, String report) {
         if (VDBG) log("setReport(" + device + "), reportType=" + reportType + " report=" + report);
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.setReport(device, reportType, report, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setReport(device, reportType, report, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -699,16 +750,20 @@
     public boolean sendData(BluetoothDevice device, String report) {
         if (DBG) log("sendData(" + device + "), report=" + report);
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.sendData(device, report, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.sendData(device, report, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -724,16 +779,20 @@
     public boolean getIdleTime(BluetoothDevice device) {
         if (DBG) log("getIdletime(" + device + ")");
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getIdleTime(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.getIdleTime(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -750,16 +809,20 @@
     public boolean setIdleTime(BluetoothDevice device, byte idleTime) {
         if (DBG) log("setIdletime(" + device + "), idleTime=" + idleTime);
         final IBluetoothHidHost service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.setIdleTime(device, idleTime, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setIdleTime(device, idleTime, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     private static void log(String msg) {
diff --git a/core/java/android/bluetooth/BluetoothLeAudio.java b/core/java/android/bluetooth/BluetoothLeAudio.java
index 34398eb..15db686 100644
--- a/core/java/android/bluetooth/BluetoothLeAudio.java
+++ b/core/java/android/bluetooth/BluetoothLeAudio.java
@@ -17,6 +17,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -27,14 +29,16 @@
 import android.bluetooth.annotations.RequiresLegacyBluetoothPermission;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.CloseGuard;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the public APIs to control the LeAudio profile.
@@ -331,7 +335,7 @@
                     IBluetoothLeAudio.class.getName()) {
                 @Override
                 public IBluetoothLeAudio getServiceInterface(IBinder service) {
-                    return IBluetoothLeAudio.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothLeAudio.Stub.asInterface(service);
                 }
     };
 
@@ -385,17 +389,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean connect(@Nullable BluetoothDevice device) {
         if (DBG) log("connect(" + device + ")");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled() && isValidDevice(device)) {
-                return service.connect(device, mAttributionSource);
+        final IBluetoothLeAudio service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -425,17 +433,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean disconnect(@Nullable BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled() && isValidDevice(device)) {
-                return service.disconnect(device, mAttributionSource);
+        final IBluetoothLeAudio service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -446,18 +458,24 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public @NonNull List<BluetoothDevice> getConnectedDevices() {
         if (VDBG) log("getConnectedDevices()");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled()) {
+        final IBluetoothLeAudio service = getService();
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return new ArrayList<BluetoothDevice>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new ArrayList<BluetoothDevice>();
         }
+        return defaultValue;
     }
 
     /**
@@ -469,19 +487,24 @@
     public @NonNull List<BluetoothDevice> getDevicesMatchingConnectionStates(
             @NonNull int[] states) {
         if (VDBG) log("getDevicesMatchingStates()");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled()) {
+        final IBluetoothLeAudio service = getService();
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return new ArrayList<BluetoothDevice>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new ArrayList<BluetoothDevice>();
         }
+        return defaultValue;
     }
 
     /**
@@ -493,18 +516,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public @BtProfileState int getConnectionState(@NonNull BluetoothDevice device) {
         if (VDBG) log("getState(" + device + ")");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled()
-                    && isValidDevice(device)) {
-                return service.getConnectionState(device, mAttributionSource);
+        final IBluetoothLeAudio service = getService();
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return BluetoothProfile.STATE_DISCONNECTED;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return BluetoothProfile.STATE_DISCONNECTED;
         }
+        return defaultValue;
     }
 
     /**
@@ -531,19 +557,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean setActiveDevice(@Nullable BluetoothDevice device) {
         if (DBG) log("setActiveDevice(" + device + ")");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled()
-                    && ((device == null) || isValidDevice(device))) {
-                service.setActiveDevice(device, mAttributionSource);
-                return true;
+        final IBluetoothLeAudio service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled() && ((device == null) || isValidDevice(device))) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setActiveDevice(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -557,19 +585,25 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public List<BluetoothDevice> getActiveDevices() {
-        if (VDBG) log("getActiveDevices()");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled()) {
+        if (VDBG) log("getActiveDevice()");
+        final IBluetoothLeAudio service = getService();
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getActiveDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getActiveDevices(mAttributionSource), mAttributionSource);
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return new ArrayList<>();
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return new ArrayList<>();
         }
+        return defaultValue;
     }
 
     /**
@@ -583,17 +617,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public int getGroupId(@NonNull BluetoothDevice device) {
         if (VDBG) log("getGroupId()");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled()) {
-                return service.getGroupId(device, mAttributionSource);
+        final IBluetoothLeAudio service = getService();
+        final int defaultValue = GROUP_ID_INVALID;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getGroupId(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return GROUP_ID_INVALID;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return GROUP_ID_INVALID;
         }
+        return defaultValue;
     }
 
     /**
@@ -606,17 +644,18 @@
     @RequiresPermission(allOf={android.Manifest.permission.BLUETOOTH_CONNECT, android.Manifest.permission.BLUETOOTH_PRIVILEGED})
     public void setVolume(int volume) {
         if (VDBG) log("setVolume(vol: " + volume + " )");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled()) {
-                service.setVolume(volume, mAttributionSource);
-                return;
+        final IBluetoothLeAudio service = getService();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled()) {
+            try {
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.setVolume(volume, mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return;
         }
     }
 
@@ -635,16 +674,20 @@
     public boolean groupAddNode(int group_id, @NonNull BluetoothDevice device) {
         if (VDBG) log("groupAddNode()");
         final IBluetoothLeAudio service = getService();
-        try {
-            if (service != null && mAdapter.isEnabled()) {
-                return service.groupAddNode(group_id, device, mAttributionSource);
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.groupAddNode(group_id, device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -663,16 +706,20 @@
     public boolean groupRemoveNode(int group_id, @NonNull BluetoothDevice device) {
         if (VDBG) log("groupRemoveNode()");
         final IBluetoothLeAudio service = getService();
-        try {
-            if (service != null && mAdapter.isEnabled()) {
-                return service.groupRemoveNode(group_id, device, mAttributionSource);
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.groupRemoveNode(group_id, device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -695,22 +742,23 @@
     public boolean setConnectionPolicy(@NonNull BluetoothDevice device,
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled()
-                    && isValidDevice(device)) {
-                if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                        && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                    return false;
-                }
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
+        final IBluetoothLeAudio service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled() && isValidDevice(device)
+                    && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                        || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -728,18 +776,21 @@
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public @ConnectionPolicy int getConnectionPolicy(@Nullable BluetoothDevice device) {
         if (VDBG) log("getConnectionPolicy(" + device + ")");
-        try {
-            final IBluetoothLeAudio service = getService();
-            if (service != null && mAdapter.isEnabled()
-                    && isValidDevice(device)) {
-                return service.getConnectionPolicy(device, mAttributionSource);
+        final IBluetoothLeAudio service = getService();
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (mAdapter.isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
         }
+        return defaultValue;
     }
 
 
diff --git a/core/java/android/bluetooth/BluetoothMap.java b/core/java/android/bluetooth/BluetoothMap.java
index 474e41f..56e4972 100644
--- a/core/java/android/bluetooth/BluetoothMap.java
+++ b/core/java/android/bluetooth/BluetoothMap.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.NonNull;
 import android.annotation.RequiresNoPermission;
@@ -28,15 +30,17 @@
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.Build;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.CloseGuard;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the APIs to control the Bluetooth MAP
@@ -87,7 +91,7 @@
                     "BluetoothMap", IBluetoothMap.class.getName()) {
                 @Override
                 public IBluetoothMap getServiceInterface(IBinder service) {
-                    return IBluetoothMap.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothMap.Stub.asInterface(service);
                 }
     };
 
@@ -142,17 +146,20 @@
     public int getState() {
         if (VDBG) log("getState()");
         final IBluetoothMap service = getService();
-        if (service != null) {
-            try {
-                return service.getState(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final int defaultValue = BluetoothMap.STATE_ERROR;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
             if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getState(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return BluetoothMap.STATE_ERROR;
+        return defaultValue;
     }
 
     /**
@@ -168,18 +175,23 @@
     public BluetoothDevice getClient() {
         if (VDBG) log("getClient()");
         final IBluetoothMap service = getService();
-        if (service != null) {
-            try {
-                return Attributable.setAttributionSource(
-                        service.getClient(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final BluetoothDevice defaultValue = null;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
             if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<BluetoothDevice> recv =
+                        new SynchronousResultReceiver();
+                service.getClient(mAttributionSource, recv);
+                return Attributable.setAttributionSource(
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return null;
+        return defaultValue;
     }
 
     /**
@@ -194,17 +206,20 @@
     public boolean isConnected(BluetoothDevice device) {
         if (VDBG) log("isConnected(" + device + ")");
         final IBluetoothMap service = getService();
-        if (service != null) {
-            try {
-                return service.isConnected(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
             if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isConnected(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -233,16 +248,20 @@
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
         final IBluetoothMap service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.disconnect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -284,17 +303,23 @@
     public @NonNull List<BluetoothDevice> getConnectedDevices() {
         if (DBG) log("getConnectedDevices()");
         final IBluetoothMap service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -309,18 +334,23 @@
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (DBG) log("getDevicesMatchingStates()");
         final IBluetoothMap service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -335,16 +365,21 @@
     public int getConnectionState(BluetoothDevice device) {
         if (DBG) log("getConnectionState(" + device + ")");
         final IBluetoothMap service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -390,20 +425,22 @@
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
         final IBluetoothMap service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                    && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                return false;
-            }
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                    && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                        || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
             try {
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -446,16 +483,20 @@
     public @ConnectionPolicy int getConnectionPolicy(@NonNull BluetoothDevice device) {
         if (VDBG) log("getConnectionPolicy(" + device + ")");
         final IBluetoothMap service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionPolicy(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        return defaultValue;
     }
 
     private static void log(String msg) {
diff --git a/core/java/android/bluetooth/BluetoothMapClient.java b/core/java/android/bluetooth/BluetoothMapClient.java
index 8a3f801..03536f9a 100644
--- a/core/java/android/bluetooth/BluetoothMapClient.java
+++ b/core/java/android/bluetooth/BluetoothMapClient.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -29,15 +31,17 @@
 import android.content.AttributionSource;
 import android.content.Context;
 import android.net.Uri;
-import android.os.Binder;
 import android.os.Build;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the APIs to control the Bluetooth MAP MCE Profile.
@@ -180,7 +184,7 @@
                     "BluetoothMapClient", IBluetoothMapClient.class.getName()) {
                 @Override
                 public IBluetoothMapClient getServiceInterface(IBinder service) {
-                    return IBluetoothMapClient.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothMapClient.Stub.asInterface(service);
                 }
     };
 
@@ -221,17 +225,20 @@
     public boolean isConnected(BluetoothDevice device) {
         if (VDBG) Log.d(TAG, "isConnected(" + device + ")");
         final IBluetoothMapClient service = getService();
-        if (service != null) {
-            try {
-                return service.isConnected(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
             if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isConnected(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -248,17 +255,20 @@
     public boolean connect(BluetoothDevice device) {
         if (DBG) Log.d(TAG, "connect(" + device + ")" + "for MAPS MCE");
         final IBluetoothMapClient service = getService();
-        if (service != null) {
-            try {
-                return service.connect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
             if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -277,15 +287,20 @@
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) Log.d(TAG, "disconnect(" + device + ")");
         final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.disconnect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -300,17 +315,23 @@
     public List<BluetoothDevice> getConnectedDevices() {
         if (DBG) Log.d(TAG, "getConnectedDevices()");
         final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<>();
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<>();
+        return defaultValue;
     }
 
     /**
@@ -325,18 +346,23 @@
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (DBG) Log.d(TAG, "getDevicesMatchingStates()");
         final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<>();
+        return defaultValue;
     }
 
     /**
@@ -351,16 +377,20 @@
     public int getConnectionState(BluetoothDevice device) {
         if (DBG) Log.d(TAG, "getConnectionState(" + device + ")");
         final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue =  BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver<>();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -405,20 +435,22 @@
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) Log.d(TAG, "setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
         final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                    && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                return false;
-            }
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
             try {
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -460,16 +492,20 @@
     public @ConnectionPolicy int getConnectionPolicy(@NonNull BluetoothDevice device) {
         if (VDBG) Log.d(TAG, "getConnectionPolicy(" + device + ")");
         final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionPolicy(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        return defaultValue;
     }
 
     /**
@@ -494,18 +530,8 @@
     public boolean sendMessage(@NonNull BluetoothDevice device, @NonNull Collection<Uri> contacts,
             @NonNull String message, @Nullable PendingIntent sentIntent,
             @Nullable PendingIntent deliveredIntent) {
-        if (DBG) Log.d(TAG, "sendMessage(" + device + ", " + contacts + ", " + message);
-        final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            try {
-                return service.sendMessage(device, contacts.toArray(new Uri[contacts.size()]),
-                        message, sentIntent, deliveredIntent, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
-            }
-        }
-        return false;
+        return sendMessage(device, contacts.toArray(new Uri[contacts.size()]), message, sentIntent,
+                deliveredIntent);
     }
 
      /**
@@ -531,16 +557,21 @@
             PendingIntent sentIntent, PendingIntent deliveredIntent) {
         if (DBG) Log.d(TAG, "sendMessage(" + device + ", " + contacts + ", " + message);
         final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.sendMessage(device, contacts, message, sentIntent, deliveredIntent,
-                        mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.sendMessage(device, contacts, message, sentIntent, deliveredIntent,
+                        mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -558,15 +589,20 @@
     public boolean getUnreadMessages(BluetoothDevice device) {
         if (DBG) Log.d(TAG, "getUnreadMessages(" + device + ")");
         final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getUnreadMessages(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.getUnreadMessages(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -580,13 +616,21 @@
     @RequiresBluetoothConnectPermission
     @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
     public boolean isUploadingSupported(BluetoothDevice device) {
+        if (DBG) Log.d(TAG, "isUploadingSupported(" + device + ")");
         final IBluetoothMapClient service = getService();
-        try {
-            return (service != null && isEnabled() && isValidDevice(device))
-                    && ((service.getSupportedFeatures(device, mAttributionSource)
-                            & UPLOADING_FEATURE_BITMASK) > 0);
-        } catch (RemoteException e) {
-            Log.e(TAG, e.getMessage());
+        final int defaultValue = 0;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getSupportedFeatures(device, mAttributionSource, recv);
+                return (recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue)
+                        & UPLOADING_FEATURE_BITMASK) > 0;
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
         return false;
     }
@@ -615,16 +659,21 @@
     public boolean setMessageStatus(BluetoothDevice device, String handle, int status) {
         if (DBG) Log.d(TAG, "setMessageStatus(" + device + ", " + handle + ", " + status + ")");
         final IBluetoothMapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device) && handle != null &&
-            (status == READ || status == UNREAD || status == UNDELETED  || status == DELETED)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) Log.d(TAG, Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device) && handle != null && (status == READ
+                    || status == UNREAD || status == UNDELETED  || status == DELETED)) {
             try {
-                return service.setMessageStatus(device, handle, status, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setMessageStatus(device, handle, status, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        return false;
+        return defaultValue;
     }
 
     private boolean isEnabled() {
diff --git a/core/java/android/bluetooth/BluetoothPan.java b/core/java/android/bluetooth/BluetoothPan.java
index ac7a52d..d4ad4ef4 100644
--- a/core/java/android/bluetooth/BluetoothPan.java
+++ b/core/java/android/bluetooth/BluetoothPan.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.RequiresPermission;
@@ -28,16 +30,18 @@
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.Build;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the APIs to control the Bluetooth Pan
@@ -188,7 +192,7 @@
                     "BluetoothPan", IBluetoothPan.class.getName()) {
                 @Override
                 public IBluetoothPan getServiceInterface(IBinder service) {
-                    return IBluetoothPan.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothPan.Stub.asInterface(service);
                 }
     };
 
@@ -249,16 +253,20 @@
     public boolean connect(BluetoothDevice device) {
         if (DBG) log("connect(" + device + ")");
         final IBluetoothPan service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.connect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -289,16 +297,20 @@
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
         final IBluetoothPan service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.disconnect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -322,22 +334,23 @@
     public boolean setConnectionPolicy(@NonNull BluetoothDevice device,
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
-        try {
-            final IBluetoothPan service = getService();
-            if (service != null && isEnabled()
-                    && isValidDevice(device)) {
-                if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                        && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                    return false;
-                }
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
+        final IBluetoothPan service = getService();
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null) Log.w(TAG, "Proxy not attached to service");
-            return false;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-            return false;
         }
+        return defaultValue;
     }
 
     /**
@@ -354,17 +367,23 @@
     public @NonNull List<BluetoothDevice> getConnectedDevices() {
         if (VDBG) log("getConnectedDevices()");
         final IBluetoothPan service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -381,18 +400,23 @@
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (VDBG) log("getDevicesMatchingStates()");
         final IBluetoothPan service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -409,16 +433,20 @@
     public int getConnectionState(@NonNull BluetoothDevice device) {
         if (VDBG) log("getState(" + device + ")");
         final IBluetoothPan service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -438,11 +466,16 @@
         String pkgName = mContext.getOpPackageName();
         if (DBG) log("setBluetoothTethering(" + value + "), calling package:" + pkgName);
         final IBluetoothPan service = getService();
-        if (service != null && isEnabled()) {
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
-                service.setBluetoothTethering(value, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.setBluetoothTethering(value, mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
     }
@@ -459,14 +492,20 @@
     public boolean isTetheringOn() {
         if (VDBG) log("isTetheringOn()");
         final IBluetoothPan service = getService();
-        if (service != null && isEnabled()) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
-                return service.isTetheringOn(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isTetheringOn(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        return false;
+        return defaultValue;
     }
 
     @UnsupportedAppUsage
diff --git a/core/java/android/bluetooth/BluetoothPbapClient.java b/core/java/android/bluetooth/BluetoothPbapClient.java
index cc91ad2..e096de8 100644
--- a/core/java/android/bluetooth/BluetoothPbapClient.java
+++ b/core/java/android/bluetooth/BluetoothPbapClient.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.NonNull;
 import android.annotation.RequiresPermission;
@@ -24,13 +26,15 @@
 import android.bluetooth.annotations.RequiresBluetoothConnectPermission;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the APIs to control the Bluetooth PBAP Client Profile.
@@ -64,7 +68,7 @@
                     "BluetoothPbapClient", IBluetoothPbapClient.class.getName()) {
                 @Override
                 public IBluetoothPbapClient getServiceInterface(IBinder service) {
-                    return IBluetoothPbapClient.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothPbapClient.Stub.asInterface(service);
                 }
     };
 
@@ -123,18 +127,20 @@
             log("connect(" + device + ") for PBAP Client.");
         }
         final IBluetoothPbapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            try {
-                return service.connect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
-            }
-        }
+        final boolean defaultValue = false;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.connect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -155,19 +161,21 @@
             log("disconnect(" + device + ")" + new Exception());
         }
         final IBluetoothPbapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            try {
-                service.disconnect(device, mAttributionSource);
-                return true;
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
-            }
-        }
+        final boolean defaultValue = true;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+                return true;
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -184,19 +192,23 @@
             log("getConnectedDevices()");
         }
         final IBluetoothPbapClient service = getService();
-        if (service != null && isEnabled()) {
-            try {
-                return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
-            }
-        }
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
+                return Attributable.setAttributionSource(
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -212,20 +224,23 @@
             log("getDevicesMatchingStates()");
         }
         final IBluetoothPbapClient service = getService();
-        if (service != null && isEnabled()) {
-            try {
-                return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
-                        mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
-            }
-        }
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
+                return Attributable.setAttributionSource(
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -241,18 +256,20 @@
             log("getConnectionState(" + device + ")");
         }
         final IBluetoothPbapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
-            }
-        }
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     private static void log(String msg) {
@@ -311,22 +328,22 @@
             log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
         }
         final IBluetoothPbapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                    && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                return false;
-            }
-            try {
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
-            }
-        }
+        final boolean defaultValue = false;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -370,17 +387,19 @@
             log("getConnectionPolicy(" + device + ")");
         }
         final IBluetoothPbapClient service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            try {
-                return service.getConnectionPolicy(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
-            }
-        }
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
         if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        return defaultValue;
     }
 }
diff --git a/core/java/android/bluetooth/BluetoothSap.java b/core/java/android/bluetooth/BluetoothSap.java
index ab2b8ea..808fa39 100644
--- a/core/java/android/bluetooth/BluetoothSap.java
+++ b/core/java/android/bluetooth/BluetoothSap.java
@@ -16,6 +16,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.RequiresNoPermission;
 import android.annotation.RequiresPermission;
@@ -26,14 +28,16 @@
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.Build;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the APIs to control the Bluetooth SIM
@@ -104,7 +108,7 @@
                     "BluetoothSap", IBluetoothSap.class.getName()) {
                 @Override
                 public IBluetoothSap getServiceInterface(IBinder service) {
-                    return IBluetoothSap.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothSap.Stub.asInterface(service);
                 }
     };
 
@@ -155,17 +159,20 @@
     public int getState() {
         if (VDBG) log("getState()");
         final IBluetoothSap service = getService();
-        if (service != null) {
-            try {
-                return service.getState(mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final int defaultValue = BluetoothSap.STATE_ERROR;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
             if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getState(mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return BluetoothSap.STATE_ERROR;
+        return defaultValue;
     }
 
     /**
@@ -180,18 +187,23 @@
     public BluetoothDevice getClient() {
         if (VDBG) log("getClient()");
         final IBluetoothSap service = getService();
-        if (service != null) {
-            try {
-                return Attributable.setAttributionSource(
-                        service.getClient(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final BluetoothDevice defaultValue = null;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
             if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<BluetoothDevice> recv =
+                        new SynchronousResultReceiver();
+                service.getClient(mAttributionSource, recv);
+                return Attributable.setAttributionSource(
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return null;
+        return defaultValue;
     }
 
     /**
@@ -206,17 +218,20 @@
     public boolean isConnected(BluetoothDevice device) {
         if (VDBG) log("isConnected(" + device + ")");
         final IBluetoothSap service = getService();
-        if (service != null) {
-            try {
-                return service.isConnected(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, e.toString());
-            }
-        } else {
+        final boolean defaultValue = false;
+        if (service == null) {
             Log.w(TAG, "Proxy not attached to service");
             if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.isConnected(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
+            }
         }
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -244,16 +259,20 @@
     public boolean disconnect(BluetoothDevice device) {
         if (DBG) log("disconnect(" + device + ")");
         final IBluetoothSap service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.disconnect(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.disconnect(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -267,17 +286,23 @@
     public List<BluetoothDevice> getConnectedDevices() {
         if (DBG) log("getConnectedDevices()");
         final IBluetoothSap service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -291,18 +316,23 @@
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (DBG) log("getDevicesMatchingStates()");
         final IBluetoothSap service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -316,16 +346,20 @@
     public int getConnectionState(BluetoothDevice device) {
         if (DBG) log("getConnectionState(" + device + ")");
         final IBluetoothSap service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -370,20 +404,22 @@
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
         final IBluetoothSap service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                    && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                return false;
-            }
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
             try {
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -425,16 +461,20 @@
     public @ConnectionPolicy int getConnectionPolicy(BluetoothDevice device) {
         if (VDBG) log("getConnectionPolicy(" + device + ")");
         final IBluetoothSap service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionPolicy(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        return defaultValue;
     }
 
     private static void log(String msg) {
diff --git a/core/java/android/bluetooth/BluetoothUtils.java b/core/java/android/bluetooth/BluetoothUtils.java
new file mode 100644
index 0000000..8674692
--- /dev/null
+++ b/core/java/android/bluetooth/BluetoothUtils.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.bluetooth;
+
+import java.time.Duration;
+
+/**
+ * {@hide}
+ */
+public final class BluetoothUtils {
+    /**
+     * This utility class cannot be instantiated
+     */
+    private BluetoothUtils() {}
+
+    /**
+     * Timeout value for synchronous binder call
+     */
+    private static final Duration SYNC_CALLS_TIMEOUT = Duration.ofSeconds(5);
+
+    /**
+     * @return timeout value for synchronous binder call
+     */
+    static Duration getSyncTimeout() {
+        return SYNC_CALLS_TIMEOUT;
+    }
+}
diff --git a/core/java/android/bluetooth/BluetoothVolumeControl.java b/core/java/android/bluetooth/BluetoothVolumeControl.java
index ba83eca..27532aa 100644
--- a/core/java/android/bluetooth/BluetoothVolumeControl.java
+++ b/core/java/android/bluetooth/BluetoothVolumeControl.java
@@ -17,6 +17,8 @@
 
 package android.bluetooth;
 
+import static android.bluetooth.BluetoothUtils.getSyncTimeout;
+
 import android.Manifest;
 import android.annotation.IntRange;
 import android.annotation.NonNull;
@@ -29,14 +31,16 @@
 import android.bluetooth.annotations.RequiresBluetoothConnectPermission;
 import android.content.AttributionSource;
 import android.content.Context;
-import android.os.Binder;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.CloseGuard;
 import android.util.Log;
 
+import com.android.modules.utils.SynchronousResultReceiver;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class provides the public APIs to control the Bluetooth Volume Control service.
@@ -86,7 +90,7 @@
                     IBluetoothVolumeControl.class.getName()) {
                 @Override
                 public IBluetoothVolumeControl getServiceInterface(IBinder service) {
-                    return IBluetoothVolumeControl.Stub.asInterface(Binder.allowBlocking(service));
+                    return IBluetoothVolumeControl.Stub.asInterface(service);
                 }
             };
 
@@ -134,17 +138,23 @@
     public @NonNull List<BluetoothDevice> getConnectedDevices() {
         if (DBG) log("getConnectedDevices()");
         final IBluetoothVolumeControl service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getConnectedDevices(mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
+                        mAttributionSource);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -159,18 +169,23 @@
     public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
         if (DBG) log("getDevicesMatchingStates()");
         final IBluetoothVolumeControl service = getService();
-        if (service != null && isEnabled()) {
+        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
             try {
+                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
+                        new SynchronousResultReceiver();
+                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                 return Attributable.setAttributionSource(
-                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
+                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                         mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return new ArrayList<BluetoothDevice>();
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return new ArrayList<BluetoothDevice>();
+        return defaultValue;
     }
 
     /**
@@ -185,16 +200,20 @@
     public int getConnectionState(BluetoothDevice device) {
         if (DBG) log("getConnectionState(" + device + ")");
         final IBluetoothVolumeControl service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionState(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.STATE_DISCONNECTED;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionState(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.STATE_DISCONNECTED;
+        return defaultValue;
     }
 
     /**
@@ -212,18 +231,19 @@
     })
     public void setVolume(@Nullable BluetoothDevice device,
             @IntRange(from = 0, to = 255) int volume) {
-        if (DBG)
-            log("setVolume(" + volume + ")");
+        if (DBG) log("setVolume(" + volume + ")");
         final IBluetoothVolumeControl service = getService();
-        try {
-            if (service != null && isEnabled()) {
-                service.setVolume(device, volume, mAttributionSource);
-                return;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled()) {
+            try {
+                final SynchronousResultReceiver recv = new SynchronousResultReceiver();
+                service.setVolume(device, volume, mAttributionSource, recv);
+                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
-            if (service == null)
-                Log.w(TAG, "Proxy not attached to service");
-        } catch (RemoteException e) {
-            Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
         }
     }
 
@@ -249,20 +269,22 @@
             @ConnectionPolicy int connectionPolicy) {
         if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
         final IBluetoothVolumeControl service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
-            if (connectionPolicy != BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
-                    && connectionPolicy != BluetoothProfile.CONNECTION_POLICY_ALLOWED) {
-                return false;
-            }
+        final boolean defaultValue = false;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)
+                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
+                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
             try {
-                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return false;
+                final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return false;
+        return defaultValue;
     }
 
     /**
@@ -285,16 +307,20 @@
     public @ConnectionPolicy int getConnectionPolicy(@NonNull BluetoothDevice device) {
         if (VDBG) log("getConnectionPolicy(" + device + ")");
         final IBluetoothVolumeControl service = getService();
-        if (service != null && isEnabled() && isValidDevice(device)) {
+        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        if (service == null) {
+            Log.w(TAG, "Proxy not attached to service");
+            if (DBG) log(Log.getStackTraceString(new Throwable()));
+        } else if (isEnabled() && isValidDevice(device)) {
             try {
-                return service.getConnectionPolicy(device, mAttributionSource);
-            } catch (RemoteException e) {
-                Log.e(TAG, Log.getStackTraceString(new Throwable()));
-                return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+                final SynchronousResultReceiver<Integer> recv = new SynchronousResultReceiver();
+                service.getConnectionPolicy(device, mAttributionSource, recv);
+                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
+            } catch (RemoteException | TimeoutException e) {
+                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
             }
         }
-        if (service == null) Log.w(TAG, "Proxy not attached to service");
-        return BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
+        return defaultValue;
     }
 
     private boolean isEnabled() {