diff --git a/services/core/java/com/android/server/biometrics/sensors/BiometricScheduler.java b/services/core/java/com/android/server/biometrics/sensors/BiometricScheduler.java
index 89b638b..89e08c1 100644
--- a/services/core/java/com/android/server/biometrics/sensors/BiometricScheduler.java
+++ b/services/core/java/com/android/server/biometrics/sensors/BiometricScheduler.java
@@ -16,6 +16,8 @@
 
 package com.android.server.biometrics.sensors;
 
+import static com.android.server.biometrics.sensors.BiometricSchedulerOperation.STATE_STARTED;
+
 import android.annotation.IntDef;
 import android.annotation.MainThread;
 import android.annotation.NonNull;
@@ -28,6 +30,7 @@
 import android.os.Looper;
 import android.os.RemoteException;
 import android.os.ServiceManager;
+import android.os.UserHandle;
 import android.util.Slog;
 import android.util.proto.ProtoOutputStream;
 
@@ -35,6 +38,7 @@
 import com.android.modules.expresslog.Counter;
 import com.android.server.biometrics.BiometricSchedulerProto;
 import com.android.server.biometrics.BiometricsProto;
+import com.android.server.biometrics.Flags;
 import com.android.server.biometrics.sensors.fingerprint.GestureAvailabilityDispatcher;
 
 import java.io.PrintWriter;
@@ -48,6 +52,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.function.Consumer;
+import java.util.function.Supplier;
 
 /**
  * A scheduler for biometric HAL operations. Maintains a queue of {@link BaseClientMonitor}
@@ -56,11 +61,16 @@
  *
  * We currently assume (and require) that each biometric sensor have its own instance of a
  * {@link BiometricScheduler}.
+ *
+ * @param <T> Hal instance for starting the user.
+ * @param <U> Session associated with the current user id.
+ *
+ * TODO: (b/304604965) Update thread annotation when FLAGS_DE_HIDL is removed.
  */
 @MainThread
-public class BiometricScheduler {
+public class BiometricScheduler<T, U> {
 
-    private static final String BASE_TAG = "BiometricScheduler";
+    private static final String TAG = "BiometricScheduler";
     // Number of recent operations to keep in our logs for dumpsys
     protected static final int LOG_NUM_RECENT_OPERATIONS = 50;
 
@@ -89,30 +99,6 @@
     @Retention(RetentionPolicy.SOURCE)
     public @interface SensorType {}
 
-    public static @SensorType int sensorTypeFromFingerprintProperties(
-            @NonNull FingerprintSensorPropertiesInternal props) {
-        if (props.isAnyUdfpsType()) {
-            return SENSOR_TYPE_UDFPS;
-        }
-
-        return SENSOR_TYPE_FP_OTHER;
-    }
-
-    public static String sensorTypeToString(@SensorType int sensorType) {
-        switch (sensorType) {
-            case SENSOR_TYPE_UNKNOWN:
-                return "Unknown";
-            case SENSOR_TYPE_FACE:
-                return "Face";
-            case SENSOR_TYPE_UDFPS:
-                return "Udfps";
-            case SENSOR_TYPE_FP_OTHER:
-                return "OtherFp";
-            default:
-                return "UnknownUnknown";
-        }
-    }
-
     private static final class CrashState {
         static final int NUM_ENTRIES = 10;
         final String timestamp;
@@ -145,8 +131,8 @@
         }
     }
 
-    @NonNull protected final String mBiometricTag;
-    private final @SensorType int mSensorType;
+    @SensorType
+    private final int mSensorType;
     @Nullable private final GestureAvailabilityDispatcher mGestureAvailabilityDispatcher;
     @NonNull private final IBiometricService mBiometricService;
     @NonNull protected final Handler mHandler;
@@ -157,6 +143,43 @@
     private int mTotalOperationsHandled;
     private final int mRecentOperationsLimit;
     @NonNull private final List<Integer> mRecentOperations;
+    @Nullable private StopUserClient<U> mStopUserClient;
+    @NonNull private Supplier<Integer> mCurrentUserRetriever;
+    @Nullable private UserSwitchProvider<T, U> mUserSwitchProvider;
+
+    private class UserSwitchClientCallback implements ClientMonitorCallback {
+        @NonNull private final BaseClientMonitor mOwner;
+
+        UserSwitchClientCallback(@NonNull BaseClientMonitor owner) {
+            mOwner = owner;
+        }
+
+        @Override
+        public void onClientFinished(@NonNull BaseClientMonitor clientMonitor, boolean success) {
+            mHandler.post(() -> {
+                Slog.d(TAG, "[Client finished] " + clientMonitor + ", success: " + success);
+
+                // Set mStopUserClient to null when StopUserClient fails. Otherwise it's possible
+                // for that the queue will wait indefinitely until the field is cleared.
+                if (clientMonitor instanceof StopUserClient<?>) {
+                    if (!success) {
+                        Slog.w(TAG, "StopUserClient failed(), is the HAL stuck? "
+                                + "Clearing mStopUserClient");
+                    }
+                    mStopUserClient = null;
+                }
+                if (mCurrentOperation != null && mCurrentOperation.isFor(mOwner)) {
+                    mCurrentOperation = null;
+                } else {
+                    // can happen if the hal dies and is usually okay
+                    // do not unset the current operation that may be newer
+                    Slog.w(TAG, "operation is already null or different (reset?): "
+                            + mCurrentOperation);
+                }
+                startNextOperationIfIdle();
+            });
+        }
+    }
 
     // Internal callback, notified when an operation is complete. Notifies the requester
     // that the operation is complete, before performing internal scheduler work (such as
@@ -164,26 +187,26 @@
     private final ClientMonitorCallback mInternalCallback = new ClientMonitorCallback() {
         @Override
         public void onClientStarted(@NonNull BaseClientMonitor clientMonitor) {
-            Slog.d(getTag(), "[Started] " + clientMonitor);
+            Slog.d(TAG, "[Started] " + clientMonitor);
         }
 
         @Override
         public void onClientFinished(@NonNull BaseClientMonitor clientMonitor, boolean success) {
             mHandler.post(() -> {
                 if (mCurrentOperation == null) {
-                    Slog.e(getTag(), "[Finishing] " + clientMonitor
+                    Slog.e(TAG, "[Finishing] " + clientMonitor
                             + " but current operation is null, success: " + success
                             + ", possible lifecycle bug in clientMonitor implementation?");
                     return;
                 }
 
                 if (!mCurrentOperation.isFor(clientMonitor)) {
-                    Slog.e(getTag(), "[Ignoring Finish] " + clientMonitor + " does not match"
+                    Slog.e(TAG, "[Ignoring Finish] " + clientMonitor + " does not match"
                             + " current: " + mCurrentOperation);
                     return;
                 }
 
-                Slog.d(getTag(), "[Finishing] " + clientMonitor + ", success: " + success);
+                Slog.d(TAG, "[Finishing] " + clientMonitor + ", success: " + success);
 
                 if (mGestureAvailabilityDispatcher != null) {
                     mGestureAvailabilityDispatcher.markSensorActive(
@@ -202,13 +225,11 @@
     };
 
     @VisibleForTesting
-    public BiometricScheduler(@NonNull String tag,
-            @NonNull Handler handler,
+    public BiometricScheduler(@NonNull Handler handler,
             @SensorType int sensorType,
             @Nullable GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
             @NonNull IBiometricService biometricService,
             int recentOperationsLimit) {
-        mBiometricTag = tag;
         mHandler = handler;
         mSensorType = sensorType;
         mGestureAvailabilityDispatcher = gestureAvailabilityDispatcher;
@@ -219,49 +240,140 @@
         mRecentOperations = new ArrayList<>();
     }
 
+    @VisibleForTesting
+    public BiometricScheduler(@NonNull Handler handler,
+            @SensorType int sensorType,
+            @Nullable GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
+            @NonNull IBiometricService biometricService,
+            int recentOperationsLimit,
+            @NonNull Supplier<Integer> currentUserRetriever,
+            @Nullable UserSwitchProvider<T, U> userSwitchProvider) {
+        mHandler = handler;
+        mSensorType = sensorType;
+        mGestureAvailabilityDispatcher = gestureAvailabilityDispatcher;
+        mPendingOperations = new ArrayDeque<>();
+        mBiometricService = biometricService;
+        mCrashStates = new ArrayDeque<>();
+        mRecentOperationsLimit = recentOperationsLimit;
+        mRecentOperations = new ArrayList<>();
+        mCurrentUserRetriever = currentUserRetriever;
+        mUserSwitchProvider = userSwitchProvider;
+    }
+
+    public BiometricScheduler(@NonNull Handler handler,
+            @SensorType int sensorType,
+            @Nullable GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
+            @NonNull Supplier<Integer> currentUserRetriever,
+            @NonNull UserSwitchProvider<T, U> userSwitchProvider) {
+        this(handler, sensorType, gestureAvailabilityDispatcher,
+                IBiometricService.Stub.asInterface(ServiceManager.getService(
+                        Context.BIOMETRIC_SERVICE)), LOG_NUM_RECENT_OPERATIONS,
+                currentUserRetriever, userSwitchProvider);
+    }
+
     /**
      * Creates a new scheduler.
      *
-     * @param tag for the specific instance of the scheduler. Should be unique.
      * @param sensorType the sensorType that this scheduler is handling.
      * @param gestureAvailabilityDispatcher may be null if the sensor does not support gestures
      *                                      (such as fingerprint swipe).
      */
-    public BiometricScheduler(@NonNull String tag,
-            @SensorType int sensorType,
+    public BiometricScheduler(@SensorType int sensorType,
             @Nullable GestureAvailabilityDispatcher gestureAvailabilityDispatcher) {
-        this(tag, new Handler(Looper.getMainLooper()), sensorType, gestureAvailabilityDispatcher,
+        this(new Handler(Looper.getMainLooper()), sensorType, gestureAvailabilityDispatcher,
                 IBiometricService.Stub.asInterface(
                         ServiceManager.getService(Context.BIOMETRIC_SERVICE)),
                 LOG_NUM_RECENT_OPERATIONS);
     }
 
+    /**
+     * Returns sensor type for a fingerprint sensor.
+     */
+    @SensorType
+    public static int sensorTypeFromFingerprintProperties(
+            @NonNull FingerprintSensorPropertiesInternal props) {
+        if (props.isAnyUdfpsType()) {
+            return SENSOR_TYPE_UDFPS;
+        }
+
+        return SENSOR_TYPE_FP_OTHER;
+    }
+
     @VisibleForTesting
     public ClientMonitorCallback getInternalCallback() {
         return mInternalCallback;
     }
 
-    protected String getTag() {
-        return BASE_TAG + "/" + mBiometricTag;
+    protected void startNextOperationIfIdle() {
+        if (Flags.deHidl()) {
+            startNextOperation();
+        } else {
+            startNextOperationIfIdleLegacy();
+        }
     }
 
-    protected void startNextOperationIfIdle() {
+    protected void startNextOperation() {
         if (mCurrentOperation != null) {
-            Slog.v(getTag(), "Not idle, current operation: " + mCurrentOperation);
+            Slog.v(TAG, "Not idle, current operation: " + mCurrentOperation);
             return;
         }
         if (mPendingOperations.isEmpty()) {
-            Slog.d(getTag(), "No operations, returning to idle");
+            Slog.d(TAG, "No operations, returning to idle");
+            return;
+        }
+
+        final int currentUserId = mCurrentUserRetriever.get();
+        final int nextUserId = mPendingOperations.getFirst().getTargetUserId();
+
+        if (nextUserId == currentUserId || mPendingOperations.getFirst().isStartUserOperation()) {
+            startNextOperationIfIdleLegacy();
+        } else if (currentUserId == UserHandle.USER_NULL && mUserSwitchProvider != null) {
+            final BaseClientMonitor startClient =
+                    mUserSwitchProvider.getStartUserClient(nextUserId);
+            final UserSwitchClientCallback finishedCallback =
+                    new UserSwitchClientCallback(startClient);
+
+            Slog.d(TAG, "[Starting User] " + startClient);
+            mCurrentOperation = new BiometricSchedulerOperation(
+                    startClient, finishedCallback, STATE_STARTED);
+            startClient.start(finishedCallback);
+        } else if (mUserSwitchProvider != null) {
+            if (mStopUserClient != null) {
+                Slog.d(TAG, "[Waiting for StopUser] " + mStopUserClient);
+            } else {
+                mStopUserClient = mUserSwitchProvider
+                        .getStopUserClient(currentUserId);
+                final UserSwitchClientCallback finishedCallback =
+                        new UserSwitchClientCallback(mStopUserClient);
+
+                Slog.d(TAG, "[Stopping User] current: " + currentUserId
+                        + ", next: " + nextUserId + ". " + mStopUserClient);
+                mCurrentOperation = new BiometricSchedulerOperation(
+                        mStopUserClient, finishedCallback, STATE_STARTED);
+                mStopUserClient.start(finishedCallback);
+            }
+        } else {
+            Slog.e(TAG, "Cannot start next operation.");
+        }
+    }
+
+    protected void startNextOperationIfIdleLegacy() {
+        if (mCurrentOperation != null) {
+            Slog.v(TAG, "Not idle, current operation: " + mCurrentOperation);
+            return;
+        }
+        if (mPendingOperations.isEmpty()) {
+            Slog.d(TAG, "No operations, returning to idle");
             return;
         }
 
         mCurrentOperation = mPendingOperations.poll();
-        Slog.d(getTag(), "[Polled] " + mCurrentOperation);
+        Slog.d(TAG, "[Polled] " + mCurrentOperation);
 
         // If the operation at the front of the queue has been marked for cancellation, send
         // ERROR_CANCELED. No need to start this client.
         if (mCurrentOperation.isMarkedCanceling()) {
-            Slog.d(getTag(), "[Now Cancelling] " + mCurrentOperation);
+            Slog.d(TAG, "[Now Cancelling] " + mCurrentOperation);
             mCurrentOperation.cancel(mHandler, mInternalCallback);
             // Now we wait for the client to send its FinishCallback, which kicks off the next
             // operation.
@@ -289,7 +401,7 @@
                 // Note down current length of queue
                 final int pendingOperationsLength = mPendingOperations.size();
                 final BiometricSchedulerOperation lastOperation = mPendingOperations.peekLast();
-                Slog.e(getTag(), "[Unable To Start] " + mCurrentOperation
+                Slog.e(TAG, "[Unable To Start] " + mCurrentOperation
                         + ". Last pending operation: " + lastOperation);
 
                 // Then for each operation currently in the pending queue at the time of this
@@ -298,10 +410,10 @@
                 for (int i = 0; i < pendingOperationsLength; i++) {
                     final BiometricSchedulerOperation operation = mPendingOperations.pollFirst();
                     if (operation != null) {
-                        Slog.w(getTag(), "[Aborting Operation] " + operation);
+                        Slog.w(TAG, "[Aborting Operation] " + operation);
                         operation.abort();
                     } else {
-                        Slog.e(getTag(), "Null operation, index: " + i
+                        Slog.e(TAG, "Null operation, index: " + i
                                 + ", expected length: " + pendingOperationsLength);
                     }
                 }
@@ -317,9 +429,9 @@
                 mBiometricService.onReadyForAuthentication(
                         mCurrentOperation.getClientMonitor().getRequestId(), cookie);
             } catch (RemoteException e) {
-                Slog.e(getTag(), "Remote exception when contacting BiometricService", e);
+                Slog.e(TAG, "Remote exception when contacting BiometricService", e);
             }
-            Slog.d(getTag(), "Waiting for cookie before starting: " + mCurrentOperation);
+            Slog.d(TAG, "Waiting for cookie before starting: " + mCurrentOperation);
         }
     }
 
@@ -338,14 +450,14 @@
      */
     public void startPreparedClient(int cookie) {
         if (mCurrentOperation == null) {
-            Slog.e(getTag(), "Current operation is null");
+            Slog.e(TAG, "Current operation is null");
             return;
         }
 
         if (mCurrentOperation.startWithCookie(mInternalCallback, cookie)) {
-            Slog.d(getTag(), "[Started] Prepared client: " + mCurrentOperation);
+            Slog.d(TAG, "[Started] Prepared client: " + mCurrentOperation);
         } else {
-            Slog.e(getTag(), "[Unable To Start] Prepared client: " + mCurrentOperation);
+            Slog.e(TAG, "[Unable To Start] Prepared client: " + mCurrentOperation);
             mCurrentOperation = null;
             startNextOperationIfIdle();
         }
@@ -374,13 +486,13 @@
         if (clientMonitor.interruptsPrecedingClients()) {
             for (BiometricSchedulerOperation operation : mPendingOperations) {
                 if (operation.markCanceling()) {
-                    Slog.d(getTag(), "New client, marking pending op as canceling: " + operation);
+                    Slog.d(TAG, "New client, marking pending op as canceling: " + operation);
                 }
             }
         }
 
         mPendingOperations.add(new BiometricSchedulerOperation(clientMonitor, clientCallback));
-        Slog.d(getTag(), "[Added] " + clientMonitor
+        Slog.d(TAG, "[Added] " + clientMonitor
                 + ", new queue size: " + mPendingOperations.size());
 
         // If the new operation should interrupt preceding clients, and if the current operation is
@@ -389,7 +501,7 @@
                 && mCurrentOperation != null
                 && mCurrentOperation.isInterruptable()
                 && mCurrentOperation.isStarted()) {
-            Slog.d(getTag(), "[Cancelling Interruptable]: " + mCurrentOperation);
+            Slog.d(TAG, "[Cancelling Interruptable]: " + mCurrentOperation);
             mCurrentOperation.cancel(mHandler, mInternalCallback);
         } else {
             startNextOperationIfIdle();
@@ -401,16 +513,16 @@
      * @param token from the caller, should match the token passed in when requesting enrollment
      */
     public void cancelEnrollment(IBinder token, long requestId) {
-        Slog.d(getTag(), "cancelEnrollment, requestId: " + requestId);
+        Slog.d(TAG, "cancelEnrollment, requestId: " + requestId);
 
         if (mCurrentOperation != null
                 && canCancelEnrollOperation(mCurrentOperation, token, requestId)) {
-            Slog.d(getTag(), "Cancelling enrollment op: " + mCurrentOperation);
+            Slog.d(TAG, "Cancelling enrollment op: " + mCurrentOperation);
             mCurrentOperation.cancel(mHandler, mInternalCallback);
         } else {
             for (BiometricSchedulerOperation operation : mPendingOperations) {
                 if (canCancelEnrollOperation(operation, token, requestId)) {
-                    Slog.d(getTag(), "Cancelling pending enrollment op: " + operation);
+                    Slog.d(TAG, "Cancelling pending enrollment op: " + operation);
                     operation.markCanceling();
                 }
             }
@@ -423,16 +535,16 @@
      * @param requestId the id returned when requesting authentication
      */
     public void cancelAuthenticationOrDetection(IBinder token, long requestId) {
-        Slog.d(getTag(), "cancelAuthenticationOrDetection, requestId: " + requestId);
+        Slog.d(TAG, "cancelAuthenticationOrDetection, requestId: " + requestId);
 
         if (mCurrentOperation != null
                 && canCancelAuthOperation(mCurrentOperation, token, requestId)) {
-            Slog.d(getTag(), "Cancelling auth/detect op: " + mCurrentOperation);
+            Slog.d(TAG, "Cancelling auth/detect op: " + mCurrentOperation);
             mCurrentOperation.cancel(mHandler, mInternalCallback);
         } else {
             for (BiometricSchedulerOperation operation : mPendingOperations) {
                 if (canCancelAuthOperation(operation, token, requestId)) {
-                    Slog.d(getTag(), "Cancelling pending auth/detect op: " + operation);
+                    Slog.d(TAG, "Cancelling pending auth/detect op: " + operation);
                     operation.markCanceling();
                 }
             }
@@ -504,11 +616,11 @@
                 mCurrentOperation != null ? mCurrentOperation.toString() : null,
                 pendingOperations);
         mCrashStates.add(crashState);
-        Slog.e(getTag(), "Recorded crash state: " + crashState.toString());
+        Slog.e(TAG, "Recorded crash state: " + crashState.toString());
     }
 
     public void dump(PrintWriter pw) {
-        pw.println("Dump of BiometricScheduler " + getTag());
+        pw.println("Dump of BiometricScheduler " + TAG);
         pw.println("Type: " + mSensorType);
         pw.println("Current operation: " + mCurrentOperation);
         pw.println("Pending operations: " + mPendingOperations.size());
@@ -548,7 +660,7 @@
      * HAL dies.
      */
     public void reset() {
-        Slog.d(getTag(), "Resetting scheduler");
+        Slog.d(TAG, "Resetting scheduler");
         mPendingOperations.clear();
         mCurrentOperation = null;
     }
@@ -562,11 +674,11 @@
             return;
         }
         for (BiometricSchedulerOperation pendingOperation : mPendingOperations) {
-            Slog.d(getTag(), "[Watchdog cancelling pending] "
+            Slog.d(TAG, "[Watchdog cancelling pending] "
                     + pendingOperation.getClientMonitor());
             pendingOperation.markCancelingForWatchdog();
         }
-        Slog.d(getTag(), "[Watchdog cancelling current] "
+        Slog.d(TAG, "[Watchdog cancelling current] "
                 + mCurrentOperation.getClientMonitor());
         mCurrentOperation.cancel(mHandler, getInternalCallback());
     }
@@ -590,9 +702,23 @@
     /**
      * Handle stop user client when user switching occurs.
      */
-    public void onUserStopped() {}
+    public void onUserStopped() {
+        if (mStopUserClient == null) {
+            Slog.e(TAG, "Unexpected onUserStopped");
+            return;
+        }
+
+        Slog.d(TAG, "[OnUserStopped]: " + mStopUserClient);
+        mStopUserClient.onUserStopped();
+        mStopUserClient = null;
+    }
 
     public Handler getHandler() {
         return mHandler;
     }
+
+    @Nullable
+    public StopUserClient<?> getStopUserClient() {
+        return mStopUserClient;
+    }
 }
diff --git a/services/core/java/com/android/server/biometrics/sensors/StopUserClient.java b/services/core/java/com/android/server/biometrics/sensors/StopUserClient.java
index e8654dc..e01c4ec 100644
--- a/services/core/java/com/android/server/biometrics/sensors/StopUserClient.java
+++ b/services/core/java/com/android/server/biometrics/sensors/StopUserClient.java
@@ -30,7 +30,10 @@
 
 /**
  * Abstract class for stopping a user.
- * @param <T> Interface for stopping the user.
+ *
+ * @param <T> Session for stopping the user. It should be either an instance of
+ *            {@link com.android.server.biometrics.sensors.fingerprint.aidl.AidlSession} or
+ *            {@link com.android.server.biometrics.sensors.face.aidl.AidlSession}.
  */
 public abstract class StopUserClient<T> extends HalClientMonitor<T> {
 
diff --git a/services/core/java/com/android/server/biometrics/sensors/UserAwareBiometricScheduler.java b/services/core/java/com/android/server/biometrics/sensors/UserAwareBiometricScheduler.java
index 3753bbd..7ca10e3 100644
--- a/services/core/java/com/android/server/biometrics/sensors/UserAwareBiometricScheduler.java
+++ b/services/core/java/com/android/server/biometrics/sensors/UserAwareBiometricScheduler.java
@@ -33,10 +33,14 @@
 
 /**
  * A user-aware scheduler that requests user-switches based on scheduled operation's targetUserId.
+ * TODO (b/304604965): Remove class when Flags.FLAG_DE_HIDL is removed.
+ *
+ * @param <T> Hal instance for starting the user.
+ * @param <U> Session associated with the current user id.
  */
-public class UserAwareBiometricScheduler extends BiometricScheduler {
+public class UserAwareBiometricScheduler<T, U> extends BiometricScheduler<T, U> {
 
-    private static final String BASE_TAG = "UaBiometricScheduler";
+    private static final String TAG = "UaBiometricScheduler";
 
     /**
      * Interface to retrieve the owner's notion of the current userId. Note that even though
@@ -66,13 +70,13 @@
         @Override
         public void onClientFinished(@NonNull BaseClientMonitor clientMonitor, boolean success) {
             mHandler.post(() -> {
-                Slog.d(getTag(), "[Client finished] " + clientMonitor + ", success: " + success);
+                Slog.d(TAG, "[Client finished] " + clientMonitor + ", success: " + success);
 
                 // Set mStopUserClient to null when StopUserClient fails. Otherwise it's possible
                 // for that the queue will wait indefinitely until the field is cleared.
                 if (clientMonitor instanceof StopUserClient<?>) {
                     if (!success) {
-                        Slog.w(getTag(), "StopUserClient failed(), is the HAL stuck? "
+                        Slog.w(TAG, "StopUserClient failed(), is the HAL stuck? "
                                 + "Clearing mStopUserClient");
                     }
                     mStopUserClient = null;
@@ -82,7 +86,7 @@
                 } else {
                     // can happen if the hal dies and is usually okay
                     // do not unset the current operation that may be newer
-                    Slog.w(getTag(), "operation is already null or different (reset?): "
+                    Slog.w(TAG, "operation is already null or different (reset?): "
                             + mCurrentOperation);
                 }
                 startNextOperationIfIdle();
@@ -98,7 +102,7 @@
             @NonNull IBiometricService biometricService,
             @NonNull CurrentUserRetriever currentUserRetriever,
             @NonNull UserSwitchCallback userSwitchCallback) {
-        super(tag, handler, sensorType, gestureAvailabilityDispatcher, biometricService,
+        super(handler, sensorType, gestureAvailabilityDispatcher, biometricService,
                 LOG_NUM_RECENT_OPERATIONS);
 
         mCurrentUserRetriever = currentUserRetriever;
@@ -117,18 +121,13 @@
     }
 
     @Override
-    protected String getTag() {
-        return BASE_TAG + "/" + mBiometricTag;
-    }
-
-    @Override
     protected void startNextOperationIfIdle() {
         if (mCurrentOperation != null) {
-            Slog.v(getTag(), "Not idle, current operation: " + mCurrentOperation);
+            Slog.v(TAG, "Not idle, current operation: " + mCurrentOperation);
             return;
         }
         if (mPendingOperations.isEmpty()) {
-            Slog.d(getTag(), "No operations, returning to idle");
+            Slog.d(TAG, "No operations, returning to idle");
             return;
         }
 
@@ -143,20 +142,20 @@
             final ClientFinishedCallback finishedCallback =
                     new ClientFinishedCallback(startClient);
 
-            Slog.d(getTag(), "[Starting User] " + startClient);
+            Slog.d(TAG, "[Starting User] " + startClient);
             mCurrentOperation = new BiometricSchedulerOperation(
                     startClient, finishedCallback, STATE_STARTED);
             startClient.start(finishedCallback);
         } else {
             if (mStopUserClient != null) {
-                Slog.d(getTag(), "[Waiting for StopUser] " + mStopUserClient);
+                Slog.d(TAG, "[Waiting for StopUser] " + mStopUserClient);
             } else {
                 mStopUserClient = mUserSwitchCallback
                         .getStopUserClient(currentUserId);
                 final ClientFinishedCallback finishedCallback =
                         new ClientFinishedCallback(mStopUserClient);
 
-                Slog.d(getTag(), "[Stopping User] current: " + currentUserId
+                Slog.d(TAG, "[Stopping User] current: " + currentUserId
                         + ", next: " + nextUserId + ". " + mStopUserClient);
                 mCurrentOperation = new BiometricSchedulerOperation(
                         mStopUserClient, finishedCallback, STATE_STARTED);
@@ -168,11 +167,11 @@
     @Override
     public void onUserStopped() {
         if (mStopUserClient == null) {
-            Slog.e(getTag(), "Unexpected onUserStopped");
+            Slog.e(TAG, "Unexpected onUserStopped");
             return;
         }
 
-        Slog.d(getTag(), "[OnUserStopped]: " + mStopUserClient);
+        Slog.d(TAG, "[OnUserStopped]: " + mStopUserClient);
         mStopUserClient.onUserStopped();
         mStopUserClient = null;
     }
diff --git a/services/core/java/com/android/server/biometrics/sensors/UserSwitchProvider.java b/services/core/java/com/android/server/biometrics/sensors/UserSwitchProvider.java
new file mode 100644
index 0000000..bc5c55b
--- /dev/null
+++ b/services/core/java/com/android/server/biometrics/sensors/UserSwitchProvider.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2024 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 com.android.server.biometrics.sensors;
+
+import android.annotation.NonNull;
+
+/**
+ * Interface to get the appropriate start and stop user clients.
+ *
+ * @param <T> Hal instance for starting the user.
+ * @param <U> Session associated with the current user id.
+ */
+public interface UserSwitchProvider<T, U> {
+    @NonNull
+    StartUserClient<T, U> getStartUserClient(int newUserId);
+    @NonNull
+    StopUserClient<U> getStopUserClient(int userId);
+}
diff --git a/services/core/java/com/android/server/biometrics/sensors/face/aidl/AidlSession.java b/services/core/java/com/android/server/biometrics/sensors/face/aidl/AidlSession.java
index af46f44..3d61f99 100644
--- a/services/core/java/com/android/server/biometrics/sensors/face/aidl/AidlSession.java
+++ b/services/core/java/com/android/server/biometrics/sensors/face/aidl/AidlSession.java
@@ -53,12 +53,10 @@
         mAidlResponseHandler = aidlResponseHandler;
     }
 
-    /** The underlying {@link ISession}. */
     @NonNull public ISession getSession() {
         return mSession;
     }
 
-    /** The user id associated with the session. */
     public int getUserId() {
         return mUserId;
     }
diff --git a/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceProvider.java b/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceProvider.java
index 9fa15b8..e4ecf1a 100644
--- a/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceProvider.java
+++ b/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceProvider.java
@@ -39,6 +39,7 @@
 import android.hardware.face.IFaceServiceReceiver;
 import android.os.Binder;
 import android.os.Handler;
+import android.os.HandlerThread;
 import android.os.IBinder;
 import android.os.Looper;
 import android.os.RemoteException;
@@ -88,6 +89,8 @@
  * Provider for a single instance of the {@link IFace} HAL.
  */
 public class FaceProvider implements IBinder.DeathRecipient, ServiceProvider {
+
+    private static final String TAG = "FaceProvider";
     private static final int ENROLL_TIMEOUT_SEC = 75;
 
     private boolean mTestHalEnabled;
@@ -159,7 +162,7 @@
             @NonNull BiometricContext biometricContext,
             boolean resetLockoutRequiresChallenge) {
         this(context, biometricStateCallback, props, halInstanceName, lockoutResetDispatcher,
-                biometricContext, null /* daemon */, resetLockoutRequiresChallenge,
+                biometricContext, null /* daemon */, getHandler(), resetLockoutRequiresChallenge,
                 false /* testHalEnabled */);
     }
 
@@ -169,13 +172,19 @@
             @NonNull String halInstanceName,
             @NonNull LockoutResetDispatcher lockoutResetDispatcher,
             @NonNull BiometricContext biometricContext,
-            @Nullable IFace daemon, boolean resetLockoutRequiresChallenge,
+            @Nullable IFace daemon,
+            @NonNull Handler handler,
+            boolean resetLockoutRequiresChallenge,
             boolean testHalEnabled) {
         mContext = context;
         mBiometricStateCallback = biometricStateCallback;
         mHalInstanceName = halInstanceName;
         mFaceSensors = new SensorList<>(ActivityManager.getService());
-        mHandler = new Handler(Looper.getMainLooper());
+        if (Flags.deHidl()) {
+            mHandler = handler;
+        } else {
+            mHandler = new Handler(Looper.getMainLooper());
+        }
         mUsageStats = new UsageStats(context);
         mLockoutResetDispatcher = lockoutResetDispatcher;
         mActivityTaskManager = ActivityTaskManager.getInstance();
@@ -189,6 +198,13 @@
         initSensors(resetLockoutRequiresChallenge, props);
     }
 
+    @NonNull
+    private static Handler getHandler() {
+        HandlerThread handlerThread = new HandlerThread(TAG);
+        handlerThread.start();
+        return new Handler(handlerThread.getLooper());
+    }
+
     private void initAuthenticationBroadcastReceiver() {
         new AuthenticationStatsBroadcastReceiver(
                 mContext,
@@ -230,8 +246,8 @@
                         prop.commonProps.maxEnrollmentsPerUser, componentInfo, prop.sensorType,
                         prop.supportsDetectInteraction, prop.halControlsPreview,
                         false /* resetLockoutRequiresChallenge */);
-                final Sensor sensor = new Sensor(getTag() + "/" + sensorId, this,
-                        mContext, mHandler, internalProp, mLockoutResetDispatcher,
+                final Sensor sensor = new Sensor(this,
+                        mContext, mHandler, internalProp,
                         mBiometricContext);
                 sensor.init(mLockoutResetDispatcher, this);
                 final int userId = sensor.getLazySession().get() == null ? UserHandle.USER_NULL :
@@ -250,9 +266,8 @@
 
     private void addHidlSensors(SensorProps prop, boolean resetLockoutRequiresChallenge) {
         final int sensorId = prop.commonProps.sensorId;
-        final Sensor sensor = new HidlToAidlSensorAdapter(getTag() + "/" + sensorId, this,
-                mContext, mHandler, prop, mLockoutResetDispatcher,
-                mBiometricContext, resetLockoutRequiresChallenge,
+        final Sensor sensor = new HidlToAidlSensorAdapter(this, mContext, mHandler, prop,
+                mLockoutResetDispatcher, mBiometricContext, resetLockoutRequiresChallenge,
                 () -> {
                     //TODO: update to make this testable
                     scheduleInternalCleanup(sensorId, ActivityManager.getCurrentUser(),
@@ -279,8 +294,7 @@
 
     private void addAidlSensors(SensorProps prop, boolean resetLockoutRequiresChallenge) {
         final int sensorId = prop.commonProps.sensorId;
-        final Sensor sensor = new Sensor(getTag() + "/" + sensorId, this, mContext,
-                mHandler, prop, mLockoutResetDispatcher, mBiometricContext,
+        final Sensor sensor = new Sensor(this, mContext, mHandler, prop, mBiometricContext,
                 resetLockoutRequiresChallenge);
         sensor.init(mLockoutResetDispatcher, this);
         final int userId = sensor.getLazySession().get() == null ? UserHandle.USER_NULL :
@@ -296,7 +310,7 @@
     }
 
     private String getTag() {
-        return "FaceProvider/" + mHalInstanceName;
+        return TAG + "/" + mHalInstanceName;
     }
 
     boolean hasHalInstance() {
diff --git a/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceStopUserClient.java b/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceStopUserClient.java
index 0110ae9..e5ae8e3 100644
--- a/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceStopUserClient.java
+++ b/services/core/java/com/android/server/biometrics/sensors/face/aidl/FaceStopUserClient.java
@@ -19,6 +19,7 @@
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.content.Context;
+import android.hardware.biometrics.face.ISession;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Slog;
@@ -30,10 +31,10 @@
 
 import java.util.function.Supplier;
 
-public class FaceStopUserClient extends StopUserClient<AidlSession> {
+public class FaceStopUserClient extends StopUserClient<ISession> {
     private static final String TAG = "FaceStopUserClient";
 
-    public FaceStopUserClient(@NonNull Context context, @NonNull Supplier<AidlSession> lazyDaemon,
+    public FaceStopUserClient(@NonNull Context context, @NonNull Supplier<ISession> lazyDaemon,
             @Nullable IBinder token, int userId, int sensorId,
             @NonNull BiometricLogger logger, @NonNull BiometricContext biometricContext,
             @NonNull UserStoppedCallback callback) {
@@ -49,7 +50,7 @@
     @Override
     protected void startHalOperation() {
         try {
-            getFreshDaemon().getSession().close();
+            getFreshDaemon().close();
         } catch (RemoteException e) {
             Slog.e(TAG, "Remote exception", e);
             getCallback().onClientFinished(this, false /* success */);
diff --git a/services/core/java/com/android/server/biometrics/sensors/face/aidl/Sensor.java b/services/core/java/com/android/server/biometrics/sensors/face/aidl/Sensor.java
index 3e5c599..635e79a 100644
--- a/services/core/java/com/android/server/biometrics/sensors/face/aidl/Sensor.java
+++ b/services/core/java/com/android/server/biometrics/sensors/face/aidl/Sensor.java
@@ -58,6 +58,7 @@
 import com.android.server.biometrics.sensors.StartUserClient;
 import com.android.server.biometrics.sensors.StopUserClient;
 import com.android.server.biometrics.sensors.UserAwareBiometricScheduler;
+import com.android.server.biometrics.sensors.UserSwitchProvider;
 import com.android.server.biometrics.sensors.face.FaceUtils;
 
 import java.util.ArrayList;
@@ -71,15 +72,16 @@
  */
 public class Sensor {
 
+    private static final String TAG = "Sensor";
+
     private boolean mTestHalEnabled;
 
-    @NonNull private final String mTag;
     @NonNull private final FaceProvider mProvider;
     @NonNull private final Context mContext;
     @NonNull private final IBinder mToken;
     @NonNull private final Handler mHandler;
     @NonNull private final FaceSensorPropertiesInternal mSensorProperties;
-    @NonNull private BiometricScheduler mScheduler;
+    @NonNull private BiometricScheduler<IFace, ISession> mScheduler;
     @Nullable private LockoutTracker mLockoutTracker;
     @NonNull private final Map<Integer, Long> mAuthenticatorIds;
 
@@ -88,11 +90,9 @@
     @NonNull BiometricContext mBiometricContext;
 
 
-    Sensor(@NonNull String tag, @NonNull FaceProvider provider, @NonNull Context context,
+    Sensor(@NonNull FaceProvider provider, @NonNull Context context,
             @NonNull Handler handler, @NonNull FaceSensorPropertiesInternal sensorProperties,
-            @NonNull LockoutResetDispatcher lockoutResetDispatcher,
-            @NonNull BiometricContext biometricContext, @Nullable AidlSession session) {
-        mTag = tag;
+            @NonNull BiometricContext biometricContext) {
         mProvider = provider;
         mContext = context;
         mToken = new Binder();
@@ -102,105 +102,135 @@
         mAuthenticatorIds = new HashMap<>();
     }
 
-    Sensor(@NonNull String tag, @NonNull FaceProvider provider, @NonNull Context context,
-            @NonNull Handler handler, @NonNull FaceSensorPropertiesInternal sensorProperties,
-            @NonNull LockoutResetDispatcher lockoutResetDispatcher,
-            @NonNull BiometricContext biometricContext) {
-        this(tag, provider, context, handler, sensorProperties, lockoutResetDispatcher,
-                biometricContext, null);
-    }
-
-    public Sensor(@NonNull String tag, @NonNull FaceProvider provider, @NonNull Context context,
+    public Sensor(@NonNull FaceProvider provider, @NonNull Context context,
             @NonNull Handler handler, @NonNull SensorProps prop,
-            @NonNull LockoutResetDispatcher lockoutResetDispatcher,
             @NonNull BiometricContext biometricContext,
             boolean resetLockoutRequiresChallenge) {
-        this(tag, provider, context, handler,
+        this(provider, context, handler,
                 getFaceSensorPropertiesInternal(prop, resetLockoutRequiresChallenge),
-                lockoutResetDispatcher, biometricContext, null);
+                biometricContext);
     }
 
     /**
      * Initialize biometric scheduler, lockout tracker and session for the sensor.
      */
-    public void init(LockoutResetDispatcher lockoutResetDispatcher,
+    public void init(@NonNull LockoutResetDispatcher lockoutResetDispatcher,
+            @NonNull FaceProvider provider) {
+        if (Flags.deHidl()) {
+            setScheduler(getBiometricSchedulerForInit(lockoutResetDispatcher, provider));
+        } else {
+            setScheduler(getUserAwareBiometricSchedulerForInit(lockoutResetDispatcher, provider));
+        }
+        mLazySession = () -> mCurrentSession != null ? mCurrentSession : null;
+        mLockoutTracker = new LockoutCache();
+    }
+
+    private BiometricScheduler<IFace, ISession> getBiometricSchedulerForInit(
+            @NonNull LockoutResetDispatcher lockoutResetDispatcher,
+            @NonNull FaceProvider provider) {
+        return new BiometricScheduler<>(mHandler,
+                BiometricScheduler.SENSOR_TYPE_FACE,
+                null /* gestureAvailabilityDispatcher */,
+                () -> mCurrentSession != null ? mCurrentSession.getUserId() : UserHandle.USER_NULL,
+                new UserSwitchProvider<IFace, ISession>() {
+                    @NonNull
+                    @Override
+                    public StopUserClient<ISession> getStopUserClient(int userId) {
+                        return new FaceStopUserClient(mContext,
+                                () -> mLazySession.get().getSession(), mToken, userId,
+                                mSensorProperties.sensorId, BiometricLogger.ofUnknown(mContext),
+                                mBiometricContext, () -> mCurrentSession = null);
+                    }
+
+                    @NonNull
+                    @Override
+                    public StartUserClient<IFace, ISession> getStartUserClient(int newUserId) {
+                        final int sensorId = mSensorProperties.sensorId;
+                        final AidlResponseHandler resultController = new AidlResponseHandler(
+                                mContext, mScheduler, sensorId, newUserId,
+                                mLockoutTracker, lockoutResetDispatcher,
+                                mBiometricContext.getAuthSessionCoordinator(), () -> {
+                        },
+                                new AidlResponseHandler.AidlResponseHandlerCallback() {
+                                    @Override
+                                    public void onEnrollSuccess() {
+                                        mProvider.scheduleLoadAuthenticatorIdsForUser(sensorId,
+                                                newUserId);
+                                        mProvider.scheduleInvalidationRequest(sensorId,
+                                                newUserId);
+                                    }
+
+                                    @Override
+                                    public void onHardwareUnavailable() {
+                                        Slog.e(TAG, "Face sensor hardware unavailable.");
+                                        mCurrentSession = null;
+                                    }
+                                });
+
+                        return Sensor.this.getStartUserClient(resultController, sensorId,
+                                newUserId, provider);
+                    }
+                });
+    }
+
+    private UserAwareBiometricScheduler<IFace, ISession> getUserAwareBiometricSchedulerForInit(
+            LockoutResetDispatcher lockoutResetDispatcher,
             FaceProvider provider) {
-        mScheduler = new UserAwareBiometricScheduler(mTag,
+        return new UserAwareBiometricScheduler<>(TAG,
                 BiometricScheduler.SENSOR_TYPE_FACE, null /* gestureAvailabilityDispatcher */,
                 () -> mCurrentSession != null ? mCurrentSession.getUserId() : UserHandle.USER_NULL,
                 new UserAwareBiometricScheduler.UserSwitchCallback() {
                     @NonNull
                     @Override
-                    public StopUserClient<?> getStopUserClient(int userId) {
-                        return new FaceStopUserClient(mContext, mLazySession, mToken, userId,
-                                mSensorProperties.sensorId,
-                                BiometricLogger.ofUnknown(mContext), mBiometricContext,
-                                () -> mCurrentSession = null);
+                    public StopUserClient<ISession> getStopUserClient(int userId) {
+                        return new FaceStopUserClient(mContext,
+                                () -> mLazySession.get().getSession(), mToken, userId,
+                                mSensorProperties.sensorId, BiometricLogger.ofUnknown(mContext),
+                                mBiometricContext, () -> mCurrentSession = null);
                     }
 
                     @NonNull
                     @Override
-                    public StartUserClient<?, ?> getStartUserClient(int newUserId) {
+                    public StartUserClient<IFace, ISession> getStartUserClient(int newUserId) {
                         final int sensorId = mSensorProperties.sensorId;
+                        final AidlResponseHandler resultController = new AidlResponseHandler(
+                                mContext, mScheduler, sensorId, newUserId,
+                                mLockoutTracker, lockoutResetDispatcher,
+                                mBiometricContext.getAuthSessionCoordinator(), () -> {
+                                    Slog.e(TAG, "Face sensor hardware unavailable.");
+                                    mCurrentSession = null;
+                                });
 
-                        final AidlResponseHandler resultController;
-                        if (Flags.deHidl()) {
-                            resultController = new AidlResponseHandler(
-                                    mContext, mScheduler, sensorId, newUserId,
-                                    mLockoutTracker, lockoutResetDispatcher,
-                                    mBiometricContext.getAuthSessionCoordinator(), () -> {},
-                                    new AidlResponseHandler.AidlResponseHandlerCallback() {
-                                        @Override
-                                        public void onEnrollSuccess() {
-                                            mProvider.scheduleLoadAuthenticatorIdsForUser(sensorId,
-                                                    newUserId);
-                                            mProvider.scheduleInvalidationRequest(sensorId,
-                                                    newUserId);
-                                        }
-
-                                        @Override
-                                        public void onHardwareUnavailable() {
-                                            Slog.e(mTag, "Face sensor hardware unavailable.");
-                                            mCurrentSession = null;
-                                        }
-                                    });
-                        } else {
-                            resultController = new AidlResponseHandler(
-                                    mContext, mScheduler, sensorId, newUserId,
-                                    mLockoutTracker, lockoutResetDispatcher,
-                                    mBiometricContext.getAuthSessionCoordinator(), () -> {
-                                Slog.e(mTag, "Got ERROR_HW_UNAVAILABLE");
-                                mCurrentSession = null;
-                            });
-                        }
-
-                        final StartUserClient.UserStartedCallback<ISession> userStartedCallback =
-                                (userIdStarted, newSession, halInterfaceVersion) -> {
-                                    Slog.d(mTag, "New session created for user: "
-                                            + userIdStarted + " with hal version: "
-                                            + halInterfaceVersion);
-                                    mCurrentSession = new AidlSession(halInterfaceVersion,
-                                            newSession, userIdStarted, resultController);
-                                    if (FaceUtils.getLegacyInstance(sensorId)
-                                            .isInvalidationInProgress(mContext, userIdStarted)) {
-                                        Slog.w(mTag,
-                                                "Scheduling unfinished invalidation request for "
-                                                        + "sensor: "
-                                                        + sensorId
-                                                        + ", user: " + userIdStarted);
-                                        provider.scheduleInvalidationRequest(sensorId,
-                                                userIdStarted);
-                                    }
-                                };
-
-                        return new FaceStartUserClient(mContext, provider::getHalInstance,
-                                mToken, newUserId, mSensorProperties.sensorId,
-                                BiometricLogger.ofUnknown(mContext), mBiometricContext,
-                                resultController, userStartedCallback);
+                        return Sensor.this.getStartUserClient(resultController, sensorId,
+                                newUserId, provider);
                     }
                 });
-        mLazySession = () -> mCurrentSession != null ? mCurrentSession : null;
-        mLockoutTracker = new LockoutCache();
+    }
+
+    private FaceStartUserClient getStartUserClient(@NonNull AidlResponseHandler resultController,
+            int sensorId, int newUserId, @NonNull FaceProvider provider) {
+        final StartUserClient.UserStartedCallback<ISession> userStartedCallback =
+                (userIdStarted, newSession, halInterfaceVersion) -> {
+                    Slog.d(TAG, "New face session created for user: "
+                            + userIdStarted + " with hal version: "
+                            + halInterfaceVersion);
+                    mCurrentSession = new AidlSession(halInterfaceVersion,
+                            newSession, userIdStarted, resultController);
+                    if (FaceUtils.getLegacyInstance(sensorId)
+                            .isInvalidationInProgress(mContext, userIdStarted)) {
+                        Slog.w(TAG,
+                                "Scheduling unfinished invalidation request for "
+                                        + "face sensor: "
+                                        + sensorId
+                                        + ", user: " + userIdStarted);
+                        provider.scheduleInvalidationRequest(sensorId,
+                                userIdStarted);
+                    }
+                };
+
+        return new FaceStartUserClient(mContext, provider::getHalInstance, mToken, newUserId,
+                mSensorProperties.sensorId, BiometricLogger.ofUnknown(mContext), mBiometricContext,
+                resultController, userStartedCallback);
     }
 
     private static FaceSensorPropertiesInternal getFaceSensorPropertiesInternal(SensorProps prop,
@@ -213,13 +243,11 @@
                         info.softwareVersion));
             }
         }
-        final FaceSensorPropertiesInternal internalProp = new FaceSensorPropertiesInternal(
+        return new FaceSensorPropertiesInternal(
                 prop.commonProps.sensorId, prop.commonProps.sensorStrength,
                 prop.commonProps.maxEnrollmentsPerUser, componentInfo, prop.sensorType,
                 prop.supportsDetectInteraction, prop.halControlsPreview,
                 resetLockoutRequiresChallenge);
-
-        return internalProp;
     }
 
     @NonNull public Supplier<AidlSession> getLazySession() {
@@ -243,7 +271,7 @@
                 mProvider, this);
     }
 
-    @NonNull public BiometricScheduler getScheduler() {
+    @NonNull public BiometricScheduler<IFace, ISession> getScheduler() {
         return mScheduler;
     }
 
@@ -259,17 +287,17 @@
     }
 
     void setTestHalEnabled(boolean enabled) {
-        Slog.w(mTag, "setTestHalEnabled: " + enabled);
+        Slog.w(TAG, "Face setTestHalEnabled: " + enabled);
         if (enabled != mTestHalEnabled) {
             // The framework should retrieve a new session from the HAL.
             try {
                 if (mCurrentSession != null) {
                     // TODO(181984005): This should be scheduled instead of directly invoked
-                    Slog.d(mTag, "Closing old session");
+                    Slog.d(TAG, "Closing old face session");
                     mCurrentSession.getSession().close();
                 }
             } catch (RemoteException e) {
-                Slog.e(mTag, "RemoteException", e);
+                Slog.e(TAG, "RemoteException", e);
             }
             mCurrentSession = null;
         }
@@ -308,7 +336,7 @@
     public void onBinderDied() {
         final BaseClientMonitor client = mScheduler.getCurrentClient();
         if (client != null && client.isInterruptable()) {
-            Slog.e(mTag, "Sending ERROR_HW_UNAVAILABLE for client: " + client);
+            Slog.e(TAG, "Sending face hardware unavailable error for client: " + client);
             final ErrorConsumer errorConsumer = (ErrorConsumer) client;
             errorConsumer.onError(FaceManager.FACE_ERROR_HW_UNAVAILABLE,
                     0 /* vendorCode */);
diff --git a/services/core/java/com/android/server/biometrics/sensors/face/hidl/Face10.java b/services/core/java/com/android/server/biometrics/sensors/face/hidl/Face10.java
index 46ce0b6..5337666 100644
--- a/services/core/java/com/android/server/biometrics/sensors/face/hidl/Face10.java
+++ b/services/core/java/com/android/server/biometrics/sensors/face/hidl/Face10.java
@@ -120,7 +120,7 @@
     @NonNull private final FaceSensorPropertiesInternal mSensorProperties;
     @NonNull private final BiometricStateCallback mBiometricStateCallback;
     @NonNull private final Context mContext;
-    @NonNull private final BiometricScheduler mScheduler;
+    @NonNull private final BiometricScheduler<IBiometricsFace, AidlSession> mScheduler;
     @NonNull private final Handler mHandler;
     @NonNull private final Supplier<IBiometricsFace> mLazyDaemon;
     @NonNull private final LockoutHalImpl mLockoutTracker;
@@ -163,14 +163,15 @@
         private final int mSensorId;
         @NonNull private final Context mContext;
         @NonNull private final Handler mHandler;
-        @NonNull private final BiometricScheduler mScheduler;
+        @NonNull private final BiometricScheduler<IBiometricsFace, AidlSession> mScheduler;
         @Nullable private Callback mCallback;
         @NonNull private final LockoutHalImpl mLockoutTracker;
         @NonNull private final LockoutResetDispatcher mLockoutResetDispatcher;
 
 
         HalResultController(int sensorId, @NonNull Context context, @NonNull Handler handler,
-                @NonNull BiometricScheduler scheduler, @NonNull LockoutHalImpl lockoutTracker,
+                @NonNull BiometricScheduler<IBiometricsFace, AidlSession> scheduler,
+                @NonNull LockoutHalImpl lockoutTracker,
                 @NonNull LockoutResetDispatcher lockoutResetDispatcher) {
             mSensorId = sensorId;
             mContext = context;
@@ -352,7 +353,7 @@
             @NonNull FaceSensorPropertiesInternal sensorProps,
             @NonNull LockoutResetDispatcher lockoutResetDispatcher,
             @NonNull Handler handler,
-            @NonNull BiometricScheduler scheduler,
+            @NonNull BiometricScheduler<IBiometricsFace, AidlSession> scheduler,
             @NonNull BiometricContext biometricContext) {
         mSensorProperties = sensorProps;
         mContext = context;
@@ -395,7 +396,8 @@
             @NonNull LockoutResetDispatcher lockoutResetDispatcher) {
         final Handler handler = new Handler(Looper.getMainLooper());
         return new Face10(context, biometricStateCallback, sensorProps, lockoutResetDispatcher,
-                handler, new BiometricScheduler(TAG, BiometricScheduler.SENSOR_TYPE_FACE,
+                handler, new BiometricScheduler<>(
+                        BiometricScheduler.SENSOR_TYPE_FACE,
                         null /* gestureAvailabilityTracker */),
                 BiometricContext.getInstance(context));
     }
diff --git a/services/core/java/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSensorAdapter.java b/services/core/java/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSensorAdapter.java
index 6355cb5..a004cae4 100644
--- a/services/core/java/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSensorAdapter.java
+++ b/services/core/java/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSensorAdapter.java
@@ -20,6 +20,7 @@
 import android.annotation.Nullable;
 import android.content.Context;
 import android.content.pm.UserInfo;
+import android.hardware.biometrics.face.ISession;
 import android.hardware.biometrics.face.SensorProps;
 import android.hardware.biometrics.face.V1_0.IBiometricsFace;
 import android.os.Handler;
@@ -67,8 +68,7 @@
             };
     private LockoutHalImpl mLockoutTracker;
 
-    public HidlToAidlSensorAdapter(@NonNull String tag,
-            @NonNull FaceProvider provider,
+    public HidlToAidlSensorAdapter(@NonNull FaceProvider provider,
             @NonNull Context context,
             @NonNull Handler handler,
             @NonNull SensorProps prop,
@@ -76,15 +76,14 @@
             @NonNull BiometricContext biometricContext,
             boolean resetLockoutRequiresChallenge,
             @NonNull Runnable internalCleanupAndGetFeatureRunnable) {
-        this(tag, provider, context, handler, prop, lockoutResetDispatcher, biometricContext,
+        this(provider, context, handler, prop, lockoutResetDispatcher, biometricContext,
                 resetLockoutRequiresChallenge, internalCleanupAndGetFeatureRunnable,
                 new AuthSessionCoordinator(), null /* daemon */,
                 null /* onEnrollSuccessCallback */);
     }
 
     @VisibleForTesting
-    HidlToAidlSensorAdapter(@NonNull String tag,
-            @NonNull FaceProvider provider,
+    HidlToAidlSensorAdapter(@NonNull FaceProvider provider,
             @NonNull Context context,
             @NonNull Handler handler,
             @NonNull SensorProps prop,
@@ -95,7 +94,7 @@
             @NonNull AuthSessionCoordinator authSessionCoordinator,
             @Nullable IBiometricsFace daemon,
             @Nullable AidlResponseHandler.AidlResponseHandlerCallback aidlResponseHandlerCallback) {
-        super(tag, provider, context, handler, prop, lockoutResetDispatcher, biometricContext,
+        super(provider, context, handler, prop, biometricContext,
                 resetLockoutRequiresChallenge);
         mInternalCleanupAndGetFeatureRunnable = internalCleanupAndGetFeatureRunnable;
         mFaceProvider = provider;
@@ -124,7 +123,7 @@
 
     @Override
     public void serviceDied(long cookie) {
-        Slog.d(TAG, "HAL died.");
+        Slog.d(TAG, "Face HAL died.");
         mDaemon = null;
     }
 
@@ -140,10 +139,12 @@
     }
 
     @Override
-    public void init(LockoutResetDispatcher lockoutResetDispatcher,
-            FaceProvider provider) {
-        setScheduler(new BiometricScheduler(TAG, BiometricScheduler.SENSOR_TYPE_FACE,
-                null /* gestureAvailabilityTracker */));
+    public void init(@NonNull LockoutResetDispatcher lockoutResetDispatcher,
+            @NonNull FaceProvider provider) {
+        setScheduler(new BiometricScheduler<ISession, AidlSession>(getHandler(),
+                BiometricScheduler.SENSOR_TYPE_FACE,
+                null /* gestureAvailabilityTracker */, () -> mCurrentUserId,
+                null /* userSwitchProvider */));
         setLazySession(this::getSession);
         mLockoutTracker = new LockoutHalImpl();
     }
@@ -188,7 +189,7 @@
             return mDaemon;
         }
 
-        Slog.d(TAG, "Daemon was null, reconnecting, current operation: "
+        Slog.d(TAG, "Face daemon was null, reconnecting, current operation: "
                 + getScheduler().getCurrentClient());
 
         try {
@@ -213,7 +214,7 @@
     }
 
     @VisibleForTesting void handleUserChanged(int newUserId) {
-        Slog.d(TAG, "User changed. Current user is " + newUserId);
+        Slog.d(TAG, "User changed. Current user for face sensor is " + newUserId);
         mSession = null;
         mCurrentUserId = newUserId;
     }
diff --git a/services/core/java/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSessionAdapter.java b/services/core/java/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSessionAdapter.java
index 5daf2d4..fa95361 100644
--- a/services/core/java/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSessionAdapter.java
+++ b/services/core/java/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSessionAdapter.java
@@ -282,7 +282,7 @@
 
     @Override
     public ICancellationSignal enrollWithOptions(FaceEnrollOptions options) {
-        //Unsupported in HIDL
+        Slog.e(TAG, "enrollWithOptions unsupported in HIDL");
         return null;
     }
 
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/AidlSession.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/AidlSession.java
index 8ff105b..0d4dac0 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/AidlSession.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/AidlSession.java
@@ -51,12 +51,10 @@
         mAidlResponseHandler = aidlResponseHandler;
     }
 
-    /** The underlying {@link ISession}. */
     @NonNull public ISession getSession() {
         return mSession;
     }
 
-    /** The user id associated with the session. */
     public int getUserId() {
         return mUserId;
     }
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintProvider.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintProvider.java
index 88a11d9..c0388d1 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintProvider.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintProvider.java
@@ -46,6 +46,7 @@
 import android.hardware.fingerprint.IUdfpsOverlayController;
 import android.os.Binder;
 import android.os.Handler;
+import android.os.HandlerThread;
 import android.os.IBinder;
 import android.os.Looper;
 import android.os.RemoteException;
@@ -102,6 +103,8 @@
 @SuppressWarnings("deprecation")
 public class FingerprintProvider implements IBinder.DeathRecipient, ServiceProvider {
 
+    private static final String TAG = "FingerprintProvider";
+
     private boolean mTestHalEnabled;
 
     @NonNull
@@ -172,7 +175,7 @@
             boolean resetLockoutRequiresHardwareAuthToken) {
         this(context, biometricStateCallback, authenticationStateListeners, props, halInstanceName,
                 lockoutResetDispatcher, gestureAvailabilityDispatcher, biometricContext,
-                null /* daemon */, resetLockoutRequiresHardwareAuthToken,
+                null /* daemon */, getHandler(), resetLockoutRequiresHardwareAuthToken,
                 false /* testHalEnabled */);
     }
 
@@ -184,6 +187,7 @@
             @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
             @NonNull BiometricContext biometricContext,
             @Nullable IFingerprint daemon,
+            @NonNull Handler handler,
             boolean resetLockoutRequiresHardwareAuthToken,
             boolean testHalEnabled) {
         mContext = context;
@@ -191,7 +195,11 @@
         mAuthenticationStateListeners = authenticationStateListeners;
         mHalInstanceName = halInstanceName;
         mFingerprintSensors = new SensorList<>(ActivityManager.getService());
-        mHandler = new Handler(Looper.getMainLooper());
+        if (Flags.deHidl()) {
+            mHandler = handler;
+        } else {
+            mHandler = new Handler(Looper.getMainLooper());
+        }
         mLockoutResetDispatcher = lockoutResetDispatcher;
         mActivityTaskManager = ActivityTaskManager.getInstance();
         mTaskStackListener = new BiometricTaskStackListener();
@@ -204,6 +212,13 @@
         initSensors(resetLockoutRequiresHardwareAuthToken, props, gestureAvailabilityDispatcher);
     }
 
+    @NonNull
+    private static Handler getHandler() {
+        HandlerThread handlerThread = new HandlerThread(TAG);
+        handlerThread.start();
+        return new Handler(handlerThread.getLooper());
+    }
+
     private void initAuthenticationBroadcastReceiver() {
         new AuthenticationStatsBroadcastReceiver(
                 mContext,
@@ -262,11 +277,9 @@
                                                                 location.sensorLocationY,
                                                                 location.sensorRadius))
                                                 .collect(Collectors.toList()));
-                final Sensor sensor = new Sensor(getTag() + "/" + sensorId, this, mContext,
-                        mHandler, internalProp, mLockoutResetDispatcher,
-                        gestureAvailabilityDispatcher, mBiometricContext);
-                sensor.init(gestureAvailabilityDispatcher,
-                        mLockoutResetDispatcher);
+                final Sensor sensor = new Sensor(this, mContext, mHandler, internalProp,
+                        mBiometricContext);
+                sensor.init(gestureAvailabilityDispatcher, mLockoutResetDispatcher);
                 final int sessionUserId =
                         sensor.getLazySession().get() == null ? UserHandle.USER_NULL :
                                 sensor.getLazySession().get().getUserId();
@@ -286,10 +299,8 @@
             @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
             boolean resetLockoutRequiresHardwareAuthToken) {
         final int sensorId = prop.commonProps.sensorId;
-        final Sensor sensor = new HidlToAidlSensorAdapter(getTag() + "/"
-                + sensorId, this, mContext, mHandler,
-                prop, mLockoutResetDispatcher, gestureAvailabilityDispatcher,
-                mBiometricContext, resetLockoutRequiresHardwareAuthToken,
+        final Sensor sensor = new HidlToAidlSensorAdapter(this, mContext, mHandler, prop,
+                mLockoutResetDispatcher, mBiometricContext, resetLockoutRequiresHardwareAuthToken,
                 () -> scheduleInternalCleanup(sensorId, ActivityManager.getCurrentUser(),
                         null /* callback */));
         sensor.init(gestureAvailabilityDispatcher, mLockoutResetDispatcher);
@@ -307,14 +318,11 @@
 
     private void addAidlSensors(@NonNull SensorProps prop,
             @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
-            List<SensorLocationInternal> workaroundLocations,
+            @NonNull List<SensorLocationInternal> workaroundLocations,
             boolean resetLockoutRequiresHardwareAuthToken) {
         final int sensorId = prop.commonProps.sensorId;
-        final Sensor sensor = new Sensor(getTag() + "/" + sensorId,
-                this, mContext, mHandler,
-                prop, mLockoutResetDispatcher, gestureAvailabilityDispatcher,
-                mBiometricContext, workaroundLocations,
-                resetLockoutRequiresHardwareAuthToken);
+        final Sensor sensor = new Sensor(this, mContext, mHandler, prop, mBiometricContext,
+                workaroundLocations, resetLockoutRequiresHardwareAuthToken);
         sensor.init(gestureAvailabilityDispatcher, mLockoutResetDispatcher);
         final int sessionUserId = sensor.getLazySession().get() == null ? UserHandle.USER_NULL :
                 sensor.getLazySession().get().getUserId();
@@ -329,7 +337,7 @@
     }
 
     private String getTag() {
-        return "FingerprintProvider/" + mHalInstanceName;
+        return TAG + "/" + mHalInstanceName;
     }
 
     boolean hasHalInstance() {
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintStopUserClient.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintStopUserClient.java
index 2cc1879..394f045 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintStopUserClient.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintStopUserClient.java
@@ -19,6 +19,7 @@
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.content.Context;
+import android.hardware.biometrics.fingerprint.ISession;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Slog;
@@ -30,11 +31,11 @@
 
 import java.util.function.Supplier;
 
-public class FingerprintStopUserClient extends StopUserClient<AidlSession> {
+public class FingerprintStopUserClient extends StopUserClient<ISession> {
     private static final String TAG = "FingerprintStopUserClient";
 
     public FingerprintStopUserClient(@NonNull Context context,
-            @NonNull Supplier<AidlSession> lazyDaemon, @Nullable IBinder token, int userId,
+            @NonNull Supplier<ISession> lazyDaemon, @Nullable IBinder token, int userId,
             int sensorId,
             @NonNull BiometricLogger logger, @NonNull BiometricContext biometricContext,
             @NonNull UserStoppedCallback callback) {
@@ -50,7 +51,7 @@
     @Override
     protected void startHalOperation() {
         try {
-            getFreshDaemon().getSession().close();
+            getFreshDaemon().close();
         } catch (RemoteException e) {
             Slog.e(TAG, "Remote exception", e);
             getCallback().onClientFinished(this, false /* success */);
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/Sensor.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/Sensor.java
index dd887bb..af88c62 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/Sensor.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/aidl/Sensor.java
@@ -59,6 +59,7 @@
 import com.android.server.biometrics.sensors.StartUserClient;
 import com.android.server.biometrics.sensors.StopUserClient;
 import com.android.server.biometrics.sensors.UserAwareBiometricScheduler;
+import com.android.server.biometrics.sensors.UserSwitchProvider;
 import com.android.server.biometrics.sensors.fingerprint.FingerprintUtils;
 import com.android.server.biometrics.sensors.fingerprint.GestureAvailabilityDispatcher;
 
@@ -77,15 +78,16 @@
 @SuppressWarnings("deprecation")
 public class Sensor {
 
+    private static final String TAG = "Sensor";
+
     private boolean mTestHalEnabled;
 
-    @NonNull private final String mTag;
     @NonNull private final FingerprintProvider mProvider;
     @NonNull private final Context mContext;
     @NonNull private final IBinder mToken;
     @NonNull private final Handler mHandler;
     @NonNull private final FingerprintSensorPropertiesInternal mSensorProperties;
-    @NonNull private BiometricScheduler mScheduler;
+    @NonNull private BiometricScheduler<IFingerprint, ISession> mScheduler;
     @NonNull private LockoutTracker mLockoutTracker;
     @NonNull private final Map<Integer, Long> mAuthenticatorIds;
     @NonNull private final BiometricContext mBiometricContext;
@@ -93,13 +95,10 @@
     @Nullable AidlSession mCurrentSession;
     @NonNull private Supplier<AidlSession> mLazySession;
 
-    public Sensor(@NonNull String tag, @NonNull FingerprintProvider provider,
+    public Sensor(@NonNull FingerprintProvider provider,
             @NonNull Context context, @NonNull Handler handler,
             @NonNull FingerprintSensorPropertiesInternal sensorProperties,
-            @NonNull LockoutResetDispatcher lockoutResetDispatcher,
-            @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
             @NonNull BiometricContext biometricContext, AidlSession session) {
-        mTag = tag;
         mProvider = provider;
         mContext = context;
         mToken = new Binder();
@@ -110,41 +109,52 @@
         mCurrentSession = session;
     }
 
-    Sensor(@NonNull String tag, @NonNull FingerprintProvider provider, @NonNull Context context,
+    Sensor(@NonNull FingerprintProvider provider, @NonNull Context context,
             @NonNull Handler handler, @NonNull FingerprintSensorPropertiesInternal sensorProperties,
-            @NonNull LockoutResetDispatcher lockoutResetDispatcher,
-            @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
             @NonNull BiometricContext biometricContext) {
-        this(tag, provider, context, handler, sensorProperties, lockoutResetDispatcher,
-                gestureAvailabilityDispatcher, biometricContext, null);
+        this(provider, context, handler, sensorProperties,
+                biometricContext, null);
     }
 
-    Sensor(@NonNull String tag, @NonNull FingerprintProvider provider, @NonNull Context context,
+    Sensor(@NonNull FingerprintProvider provider, @NonNull Context context,
             @NonNull Handler handler, @NonNull SensorProps sensorProp,
-            @NonNull LockoutResetDispatcher lockoutResetDispatcher,
-            @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
             @NonNull BiometricContext biometricContext,
             @NonNull List<SensorLocationInternal> workaroundLocation,
             boolean resetLockoutRequiresHardwareAuthToken) {
-        this(tag, provider, context, handler, getFingerprintSensorPropertiesInternal(sensorProp,
+        this(provider, context, handler, getFingerprintSensorPropertiesInternal(sensorProp,
                         workaroundLocation, resetLockoutRequiresHardwareAuthToken),
-                lockoutResetDispatcher, gestureAvailabilityDispatcher, biometricContext, null);
+                biometricContext, null);
     }
 
     /**
      * Initialize biometric scheduler, lockout tracker and session for the sensor.
      */
-    public void init(GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
-            LockoutResetDispatcher lockoutResetDispatcher) {
-        mScheduler = new UserAwareBiometricScheduler(mTag,
+    public void init(@NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
+            @NonNull LockoutResetDispatcher lockoutResetDispatcher) {
+        if (Flags.deHidl()) {
+            setScheduler(getBiometricSchedulerForInit(gestureAvailabilityDispatcher,
+                    lockoutResetDispatcher));
+        } else {
+            setScheduler(getUserAwareBiometricSchedulerForInit(gestureAvailabilityDispatcher,
+                    lockoutResetDispatcher));
+        }
+        mLockoutTracker = new LockoutCache();
+        mLazySession = () -> mCurrentSession != null ? mCurrentSession : null;
+    }
+
+    private BiometricScheduler<IFingerprint, ISession> getBiometricSchedulerForInit(
+            @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
+            @NonNull LockoutResetDispatcher lockoutResetDispatcher) {
+        return new BiometricScheduler<>(mHandler,
                 BiometricScheduler.sensorTypeFromFingerprintProperties(mSensorProperties),
                 gestureAvailabilityDispatcher,
                 () -> mCurrentSession != null ? mCurrentSession.getUserId() : UserHandle.USER_NULL,
-                new UserAwareBiometricScheduler.UserSwitchCallback() {
+                new UserSwitchProvider<IFingerprint, ISession>() {
                     @NonNull
                     @Override
-                    public StopUserClient<?> getStopUserClient(int userId) {
-                        return new FingerprintStopUserClient(mContext, mLazySession, mToken,
+                    public StopUserClient<ISession> getStopUserClient(int userId) {
+                        return new FingerprintStopUserClient(mContext,
+                                () -> mLazySession.get().getSession(), mToken,
                                 userId, mSensorProperties.sensorId,
                                 BiometricLogger.ofUnknown(mContext), mBiometricContext,
                                 () -> mCurrentSession = null);
@@ -152,69 +162,100 @@
 
                     @NonNull
                     @Override
-                    public StartUserClient<?, ?> getStartUserClient(int newUserId) {
+                    public StartUserClient<IFingerprint, ISession> getStartUserClient(
+                            int newUserId) {
                         final int sensorId = mSensorProperties.sensorId;
-
-                        final AidlResponseHandler resultController;
-
-                        if (Flags.deHidl()) {
-                            resultController = new AidlResponseHandler(
-                                    mContext, mScheduler, sensorId, newUserId,
-                                    mLockoutTracker, lockoutResetDispatcher,
-                                    mBiometricContext.getAuthSessionCoordinator(), () -> {},
-                                    new AidlResponseHandler.AidlResponseHandlerCallback() {
-                                        @Override
-                                        public void onEnrollSuccess() {
-                                            mProvider.scheduleLoadAuthenticatorIdsForUser(sensorId,
-                                                    newUserId);
-                                            mProvider.scheduleInvalidationRequest(sensorId,
-                                                    newUserId);
-                                        }
-
-                                        @Override
-                                        public void onHardwareUnavailable() {
-                                            Slog.e(mTag,
-                                                    "Fingerprint sensor hardware unavailable.");
-                                            mCurrentSession = null;
-                                        }
-                                    });
-                        } else {
-                            resultController = new AidlResponseHandler(
-                                    mContext, mScheduler, sensorId, newUserId,
-                                    mLockoutTracker, lockoutResetDispatcher,
-                                    mBiometricContext.getAuthSessionCoordinator(), () -> {
-                                Slog.e(mTag, "Got ERROR_HW_UNAVAILABLE");
-                                mCurrentSession = null;
-                            });
-                        }
-
-                        final StartUserClient.UserStartedCallback<ISession> userStartedCallback =
-                                (userIdStarted, newSession, halInterfaceVersion) -> {
-                                    Slog.d(mTag, "New session created for user: "
-                                            + userIdStarted + " with hal version: "
-                                            + halInterfaceVersion);
-                                    mCurrentSession = new AidlSession(halInterfaceVersion,
-                                            newSession, userIdStarted, resultController);
-                                    if (FingerprintUtils.getInstance(sensorId)
-                                            .isInvalidationInProgress(mContext, userIdStarted)) {
-                                        Slog.w(mTag,
-                                                "Scheduling unfinished invalidation request for "
-                                                        + "sensor: "
-                                                        + sensorId
-                                                        + ", user: " + userIdStarted);
+                        final AidlResponseHandler resultController = new AidlResponseHandler(
+                                mContext, mScheduler, sensorId, newUserId,
+                                mLockoutTracker, lockoutResetDispatcher,
+                                mBiometricContext.getAuthSessionCoordinator(), () -> {},
+                                new AidlResponseHandler.AidlResponseHandlerCallback() {
+                                    @Override
+                                    public void onEnrollSuccess() {
+                                        mProvider.scheduleLoadAuthenticatorIdsForUser(sensorId,
+                                                newUserId);
                                         mProvider.scheduleInvalidationRequest(sensorId,
-                                                userIdStarted);
+                                                newUserId);
                                     }
-                                };
 
-                        return new FingerprintStartUserClient(mContext, mProvider::getHalInstance,
-                                mToken, newUserId, mSensorProperties.sensorId,
-                                BiometricLogger.ofUnknown(mContext), mBiometricContext,
-                                resultController, userStartedCallback);
+                                    @Override
+                                    public void onHardwareUnavailable() {
+                                        Slog.e(TAG,
+                                                "Fingerprint sensor hardware unavailable.");
+                                        mCurrentSession = null;
+                                    }
+                                });
+
+                        return Sensor.this.getStartUserClient(resultController, sensorId,
+                                newUserId);
                     }
                 });
-        mLockoutTracker = new LockoutCache();
-        mLazySession = () -> mCurrentSession != null ? mCurrentSession : null;
+    }
+
+    private UserAwareBiometricScheduler<ISession, AidlSession>
+            getUserAwareBiometricSchedulerForInit(
+                    GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
+                    LockoutResetDispatcher lockoutResetDispatcher) {
+        return new UserAwareBiometricScheduler<>(TAG,
+                BiometricScheduler.sensorTypeFromFingerprintProperties(mSensorProperties),
+                gestureAvailabilityDispatcher,
+                () -> mCurrentSession != null ? mCurrentSession.getUserId() : UserHandle.USER_NULL,
+                new UserAwareBiometricScheduler.UserSwitchCallback() {
+                    @NonNull
+                    @Override
+                    public StopUserClient<ISession> getStopUserClient(int userId) {
+                        return new FingerprintStopUserClient(mContext,
+                                () -> mLazySession.get().getSession(), mToken,
+                                userId, mSensorProperties.sensorId,
+                                BiometricLogger.ofUnknown(mContext), mBiometricContext,
+                                () -> mCurrentSession = null);
+                    }
+
+                    @NonNull
+                    @Override
+                    public StartUserClient<IFingerprint, ISession> getStartUserClient(
+                            int newUserId) {
+                        final int sensorId = mSensorProperties.sensorId;
+
+                        final AidlResponseHandler resultController = new AidlResponseHandler(
+                                mContext, mScheduler, sensorId, newUserId,
+                                mLockoutTracker, lockoutResetDispatcher,
+                                mBiometricContext.getAuthSessionCoordinator(), () -> {
+                                    Slog.e(TAG, "Fingerprint hardware unavailable.");
+                                    mCurrentSession = null;
+                                });
+
+                        return Sensor.this.getStartUserClient(resultController, sensorId,
+                                newUserId);
+                    }
+                });
+    }
+
+    private FingerprintStartUserClient getStartUserClient(AidlResponseHandler resultController,
+            int sensorId, int newUserId) {
+        final StartUserClient.UserStartedCallback<ISession> userStartedCallback =
+                (userIdStarted, newSession, halInterfaceVersion) -> {
+                    Slog.d(TAG, "New fingerprint session created for user: "
+                            + userIdStarted + " with hal version: "
+                            + halInterfaceVersion);
+                    mCurrentSession = new AidlSession(halInterfaceVersion,
+                            newSession, userIdStarted, resultController);
+                    if (FingerprintUtils.getInstance(sensorId)
+                            .isInvalidationInProgress(mContext, userIdStarted)) {
+                        Slog.w(TAG,
+                                "Scheduling unfinished invalidation request for "
+                                        + "fingerprint sensor: "
+                                        + sensorId
+                                        + ", user: " + userIdStarted);
+                        mProvider.scheduleInvalidationRequest(sensorId,
+                                userIdStarted);
+                    }
+                };
+
+        return new FingerprintStartUserClient(mContext, mProvider::getHalInstance,
+                mToken, newUserId, mSensorProperties.sensorId,
+                BiometricLogger.ofUnknown(mContext), mBiometricContext,
+                resultController, userStartedCallback);
     }
 
     protected static FingerprintSensorPropertiesInternal getFingerprintSensorPropertiesInternal(
@@ -267,7 +308,7 @@
                 biometricStateCallback, mProvider, this);
     }
 
-    @NonNull public BiometricScheduler getScheduler() {
+    @NonNull public BiometricScheduler<IFingerprint, ISession> getScheduler() {
         return mScheduler;
     }
 
@@ -283,17 +324,17 @@
     }
 
     void setTestHalEnabled(boolean enabled) {
-        Slog.w(mTag, "setTestHalEnabled: " + enabled);
+        Slog.w(TAG, "Fingerprint setTestHalEnabled: " + enabled);
         if (enabled != mTestHalEnabled) {
             // The framework should retrieve a new session from the HAL.
             try {
                 if (mCurrentSession != null) {
                     // TODO(181984005): This should be scheduled instead of directly invoked
-                    Slog.d(mTag, "Closing old session");
+                    Slog.d(TAG, "Closing old fingerprint session");
                     mCurrentSession.getSession().close();
                 }
             } catch (RemoteException e) {
-                Slog.e(mTag, "RemoteException", e);
+                Slog.e(TAG, "RemoteException", e);
             }
             mCurrentSession = null;
         }
@@ -335,7 +376,7 @@
     public void onBinderDied() {
         final BaseClientMonitor client = mScheduler.getCurrentClient();
         if (client instanceof ErrorConsumer) {
-            Slog.e(mTag, "Sending ERROR_HW_UNAVAILABLE for client: " + client);
+            Slog.e(TAG, "Sending fingerprint hardware unavailable error for client: " + client);
             final ErrorConsumer errorConsumer = (ErrorConsumer) client;
             errorConsumer.onError(FingerprintManager.FINGERPRINT_ERROR_HW_UNAVAILABLE,
                     0 /* vendorCode */);
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/Fingerprint21.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/Fingerprint21.java
index d3cecd0..4accf8f 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/Fingerprint21.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/Fingerprint21.java
@@ -119,7 +119,7 @@
     @NonNull private final AuthenticationStateListeners mAuthenticationStateListeners;
     private final ActivityTaskManager mActivityTaskManager;
     @NonNull private final FingerprintSensorPropertiesInternal mSensorProperties;
-    private final BiometricScheduler mScheduler;
+    private final BiometricScheduler<IBiometricsFingerprint, AidlSession> mScheduler;
     private final Handler mHandler;
     private final LockoutResetDispatcher mLockoutResetDispatcher;
     private final LockoutFrameworkImpl mLockoutTracker;
@@ -198,11 +198,11 @@
         private final int mSensorId;
         @NonNull private final Context mContext;
         @NonNull final Handler mHandler;
-        @NonNull final BiometricScheduler mScheduler;
+        @NonNull final BiometricScheduler<IBiometricsFingerprint, AidlSession> mScheduler;
         @Nullable private Callback mCallback;
 
         HalResultController(int sensorId, @NonNull Context context, @NonNull Handler handler,
-                @NonNull BiometricScheduler scheduler) {
+                @NonNull BiometricScheduler<IBiometricsFingerprint, AidlSession> scheduler) {
             mSensorId = sensorId;
             mContext = context;
             mHandler = handler;
@@ -336,7 +336,7 @@
             @NonNull BiometricStateCallback biometricStateCallback,
             @NonNull AuthenticationStateListeners authenticationStateListeners,
             @NonNull FingerprintSensorPropertiesInternal sensorProps,
-            @NonNull BiometricScheduler scheduler,
+            @NonNull BiometricScheduler<IBiometricsFingerprint, AidlSession> scheduler,
             @NonNull Handler handler,
             @NonNull LockoutResetDispatcher lockoutResetDispatcher,
             @NonNull HalResultController controller,
@@ -389,8 +389,8 @@
             @NonNull Handler handler,
             @NonNull LockoutResetDispatcher lockoutResetDispatcher,
             @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher) {
-        final BiometricScheduler scheduler =
-                new BiometricScheduler(TAG,
+        final BiometricScheduler<IBiometricsFingerprint, AidlSession> scheduler =
+                new BiometricScheduler<>(
                         BiometricScheduler.sensorTypeFromFingerprintProperties(sensorProps),
                         gestureAvailabilityDispatcher);
         final HalResultController controller = new HalResultController(sensorProps.sensorId,
@@ -533,8 +533,8 @@
     private void scheduleUpdateActiveUserWithoutHandler(int targetUserId, boolean force) {
         final boolean hasEnrolled =
                 !getEnrolledFingerprints(mSensorProperties.sensorId, targetUserId).isEmpty();
-        final FingerprintUpdateActiveUserClient client =
-                new FingerprintUpdateActiveUserClient(mContext, mLazyDaemon, targetUserId,
+        final FingerprintUpdateActiveUserClientLegacy client =
+                new FingerprintUpdateActiveUserClientLegacy(mContext, mLazyDaemon, targetUserId,
                         mContext.getOpPackageName(), mSensorProperties.sensorId,
                         createLogger(BiometricsProtoEnums.ACTION_UNKNOWN,
                                 BiometricsProtoEnums.CLIENT_UNKNOWN,
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/Fingerprint21UdfpsMock.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/Fingerprint21UdfpsMock.java
index 88dae6f..9232e11 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/Fingerprint21UdfpsMock.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/Fingerprint21UdfpsMock.java
@@ -140,9 +140,9 @@
     private static class TestableBiometricScheduler extends BiometricScheduler {
         @NonNull private Fingerprint21UdfpsMock mFingerprint21;
 
-        TestableBiometricScheduler(@NonNull String tag, @NonNull Handler handler,
+        TestableBiometricScheduler(
                 @Nullable GestureAvailabilityDispatcher gestureAvailabilityDispatcher) {
-            super(tag, BiometricScheduler.SENSOR_TYPE_FP_OTHER, gestureAvailabilityDispatcher);
+            super(BiometricScheduler.SENSOR_TYPE_FP_OTHER, gestureAvailabilityDispatcher);
         }
 
         void init(@NonNull Fingerprint21UdfpsMock fingerprint21) {
@@ -258,7 +258,7 @@
 
         final Handler handler = new Handler(Looper.getMainLooper());
         final TestableBiometricScheduler scheduler =
-                new TestableBiometricScheduler(TAG, handler, gestureAvailabilityDispatcher);
+                new TestableBiometricScheduler(gestureAvailabilityDispatcher);
         final MockHalResultController controller =
                 new MockHalResultController(sensorProps.sensorId, context, handler, scheduler);
         return new Fingerprint21UdfpsMock(context, biometricStateCallback,
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/FingerprintUpdateActiveUserClient.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/FingerprintUpdateActiveUserClient.java
index 5c5b992..59e64cd 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/FingerprintUpdateActiveUserClient.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/FingerprintUpdateActiveUserClient.java
@@ -18,7 +18,7 @@
 
 import android.annotation.NonNull;
 import android.content.Context;
-import android.hardware.biometrics.fingerprint.V2_1.IBiometricsFingerprint;
+import android.hardware.biometrics.fingerprint.ISession;
 import android.os.Build;
 import android.os.Environment;
 import android.os.RemoteException;
@@ -39,8 +39,8 @@
 /**
  * Sets the HAL's current active user, and updates the framework's authenticatorId cache.
  */
-public class FingerprintUpdateActiveUserClient extends
-        StartUserClient<IBiometricsFingerprint, AidlSession> {
+public class FingerprintUpdateActiveUserClient extends StartUserClient<ISession,
+        AidlSession> {
 
     private static final String TAG = "FingerprintUpdateActiveUserClient";
     private static final String FP_DATA_DIR = "fpdata";
@@ -52,19 +52,7 @@
     private File mDirectory;
 
     FingerprintUpdateActiveUserClient(@NonNull Context context,
-            @NonNull Supplier<IBiometricsFingerprint> lazyDaemon, int userId,
-            @NonNull String owner, int sensorId,
-            @NonNull BiometricLogger logger, @NonNull BiometricContext biometricContext,
-            @NonNull Supplier<Integer> currentUserId,
-            boolean hasEnrolledBiometrics, @NonNull Map<Integer, Long> authenticatorIds,
-            boolean forceUpdateAuthenticatorId) {
-        this(context, lazyDaemon, userId, owner, sensorId, logger, biometricContext, currentUserId,
-                hasEnrolledBiometrics, authenticatorIds, forceUpdateAuthenticatorId,
-                (newUserId, newUser, halInterfaceVersion) -> {});
-    }
-
-    FingerprintUpdateActiveUserClient(@NonNull Context context,
-            @NonNull Supplier<IBiometricsFingerprint> lazyDaemon, int userId,
+            @NonNull Supplier<ISession> lazyDaemon, int userId,
             @NonNull String owner, int sensorId,
             @NonNull BiometricLogger logger, @NonNull BiometricContext biometricContext,
             @NonNull Supplier<Integer> currentUserId,
@@ -132,9 +120,10 @@
         try {
             final int targetId = getTargetUserId();
             Slog.d(TAG, "Setting active user: " + targetId);
-            getFreshDaemon().setActiveGroup(targetId, mDirectory.getAbsolutePath());
+            HidlToAidlSessionAdapter sessionAdapter = (HidlToAidlSessionAdapter) getFreshDaemon();
+            sessionAdapter.setActiveGroup(targetId, mDirectory.getAbsolutePath());
             mAuthenticatorIds.put(targetId, mHasEnrolledBiometrics
-                    ? getFreshDaemon().getAuthenticatorId() : 0L);
+                    ? sessionAdapter.getAuthenticatorIdForUpdateClient() : 0L);
             mUserStartedCallback.onUserStarted(targetId, null, 0);
             mCallback.onClientFinished(this, true /* success */);
         } catch (RemoteException e) {
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/FingerprintUpdateActiveUserClientLegacy.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/FingerprintUpdateActiveUserClientLegacy.java
new file mode 100644
index 0000000..fc85402
--- /dev/null
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/FingerprintUpdateActiveUserClientLegacy.java
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2024 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 com.android.server.biometrics.sensors.fingerprint.hidl;
+
+import android.annotation.NonNull;
+import android.content.Context;
+import android.hardware.biometrics.fingerprint.V2_1.IBiometricsFingerprint;
+import android.os.Build;
+import android.os.Environment;
+import android.os.RemoteException;
+import android.os.SELinux;
+import android.util.Slog;
+
+import com.android.server.biometrics.BiometricsProto;
+import com.android.server.biometrics.log.BiometricContext;
+import com.android.server.biometrics.log.BiometricLogger;
+import com.android.server.biometrics.sensors.ClientMonitorCallback;
+import com.android.server.biometrics.sensors.HalClientMonitor;
+
+import java.io.File;
+import java.util.Map;
+import java.util.function.Supplier;
+
+/**
+ * TODO(b/304604965): Delete this class once Flags.DE_HIDL is ready for release.
+ */
+public class FingerprintUpdateActiveUserClientLegacy extends
+        HalClientMonitor<IBiometricsFingerprint> {
+    private static final String TAG = "FingerprintUpdateActiveUserClient";
+    private static final String FP_DATA_DIR = "fpdata";
+
+    private final Supplier<Integer> mCurrentUserId;
+    private final boolean mForceUpdateAuthenticatorId;
+    private final boolean mHasEnrolledBiometrics;
+    private final Map<Integer, Long> mAuthenticatorIds;
+    private File mDirectory;
+
+    FingerprintUpdateActiveUserClientLegacy(@NonNull Context context,
+            @NonNull Supplier<IBiometricsFingerprint> lazyDaemon, int userId,
+            @NonNull String owner, int sensorId,
+            @NonNull BiometricLogger logger, @NonNull BiometricContext biometricContext,
+            @NonNull Supplier<Integer> currentUserId,
+            boolean hasEnrolledBiometrics, @NonNull Map<Integer, Long> authenticatorIds,
+            boolean forceUpdateAuthenticatorId) {
+        super(context, lazyDaemon, null /* token */, null /* listener */, userId, owner,
+                0 /* cookie */, sensorId, logger, biometricContext);
+        mCurrentUserId = currentUserId;
+        mForceUpdateAuthenticatorId = forceUpdateAuthenticatorId;
+        mHasEnrolledBiometrics = hasEnrolledBiometrics;
+        mAuthenticatorIds = authenticatorIds;
+    }
+
+    @Override
+    public void start(@NonNull ClientMonitorCallback callback) {
+        super.start(callback);
+
+        if (mCurrentUserId.get() == getTargetUserId() && !mForceUpdateAuthenticatorId) {
+            Slog.d(TAG, "Already user: " + mCurrentUserId + ", returning");
+            callback.onClientFinished(this, true /* success */);
+            return;
+        }
+
+        int firstSdkInt = Build.VERSION.DEVICE_INITIAL_SDK_INT;
+        if (firstSdkInt < Build.VERSION_CODES.BASE) {
+            Slog.e(TAG, "First SDK version " + firstSdkInt + " is invalid; must be "
+                    + "at least VERSION_CODES.BASE");
+        }
+        File baseDir;
+        if (firstSdkInt <= Build.VERSION_CODES.O_MR1) {
+            baseDir = Environment.getUserSystemDirectory(getTargetUserId());
+        } else {
+            baseDir = Environment.getDataVendorDeDirectory(getTargetUserId());
+        }
+
+        mDirectory = new File(baseDir, FP_DATA_DIR);
+        if (!mDirectory.exists()) {
+            if (!mDirectory.mkdir()) {
+                Slog.e(TAG, "Cannot make directory: " + mDirectory.getAbsolutePath());
+                callback.onClientFinished(this, false /* success */);
+                return;
+            }
+            // Calling mkdir() from this process will create a directory with our
+            // permissions (inherited from the containing dir). This command fixes
+            // the label.
+            if (!SELinux.restorecon(mDirectory)) {
+                Slog.e(TAG, "Restorecons failed. Directory will have wrong label.");
+                callback.onClientFinished(this, false /* success */);
+                return;
+            }
+        }
+
+        startHalOperation();
+    }
+
+    @Override
+    public void unableToStart() {
+        // Nothing to do here
+    }
+
+    @Override
+    protected void startHalOperation() {
+        try {
+            final int targetId = getTargetUserId();
+            Slog.d(TAG, "Setting active user: " + targetId);
+            getFreshDaemon().setActiveGroup(targetId, mDirectory.getAbsolutePath());
+            mAuthenticatorIds.put(targetId, mHasEnrolledBiometrics
+                    ? getFreshDaemon().getAuthenticatorId() : 0L);
+            mCallback.onClientFinished(this, true /* success */);
+        } catch (RemoteException e) {
+            Slog.e(TAG, "Failed to setActiveGroup: " + e);
+            mCallback.onClientFinished(this, false /* success */);
+        }
+    }
+
+    @Override
+    public int getProtoEnum() {
+        return BiometricsProto.CM_UPDATE_ACTIVE_USER;
+    }
+}
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSensorAdapter.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSensorAdapter.java
index 0bb61415..abf48d1 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSensorAdapter.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSensorAdapter.java
@@ -20,6 +20,7 @@
 import android.annotation.Nullable;
 import android.content.Context;
 import android.content.pm.UserInfo;
+import android.hardware.biometrics.fingerprint.ISession;
 import android.hardware.biometrics.fingerprint.SensorProps;
 import android.hardware.biometrics.fingerprint.V2_1.IBiometricsFingerprint;
 import android.os.Handler;
@@ -39,7 +40,7 @@
 import com.android.server.biometrics.sensors.LockoutTracker;
 import com.android.server.biometrics.sensors.StartUserClient;
 import com.android.server.biometrics.sensors.StopUserClient;
-import com.android.server.biometrics.sensors.UserAwareBiometricScheduler;
+import com.android.server.biometrics.sensors.UserSwitchProvider;
 import com.android.server.biometrics.sensors.fingerprint.FingerprintUtils;
 import com.android.server.biometrics.sensors.fingerprint.GestureAvailabilityDispatcher;
 import com.android.server.biometrics.sensors.fingerprint.aidl.AidlResponseHandler;
@@ -71,37 +72,33 @@
                 }
             };
 
-    public HidlToAidlSensorAdapter(@NonNull String tag, @NonNull FingerprintProvider provider,
-            @NonNull Context context, @NonNull Handler handler,
+    public HidlToAidlSensorAdapter(@NonNull FingerprintProvider provider,
+            @NonNull Context context,
+            @NonNull Handler handler,
             @NonNull SensorProps prop,
             @NonNull LockoutResetDispatcher lockoutResetDispatcher,
-            @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
             @NonNull BiometricContext biometricContext,
             boolean resetLockoutRequiresHardwareAuthToken,
             @NonNull Runnable internalCleanupRunnable) {
-        this(tag, provider, context, handler, prop, lockoutResetDispatcher,
-                gestureAvailabilityDispatcher, biometricContext,
+        this(provider, context, handler, prop, lockoutResetDispatcher, biometricContext,
                 resetLockoutRequiresHardwareAuthToken, internalCleanupRunnable,
                 new AuthSessionCoordinator(), null /* daemon */,
                 null /* onEnrollSuccessCallback */);
     }
 
     @VisibleForTesting
-    HidlToAidlSensorAdapter(@NonNull String tag, @NonNull FingerprintProvider provider,
+    HidlToAidlSensorAdapter(@NonNull FingerprintProvider provider,
             @NonNull Context context, @NonNull Handler handler,
             @NonNull SensorProps prop,
             @NonNull LockoutResetDispatcher lockoutResetDispatcher,
-            @NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
             @NonNull BiometricContext biometricContext,
             boolean resetLockoutRequiresHardwareAuthToken,
             @NonNull Runnable internalCleanupRunnable,
             @NonNull AuthSessionCoordinator authSessionCoordinator,
             @Nullable IBiometricsFingerprint daemon,
             @Nullable AidlResponseHandler.AidlResponseHandlerCallback aidlResponseHandlerCallback) {
-        super(tag, provider, context, handler, getFingerprintSensorPropertiesInternal(prop,
+        super(provider, context, handler, getFingerprintSensorPropertiesInternal(prop,
                         new ArrayList<>(), resetLockoutRequiresHardwareAuthToken),
-                lockoutResetDispatcher,
-                gestureAvailabilityDispatcher,
                 biometricContext, null /* session */);
         mLockoutResetDispatcher = lockoutResetDispatcher;
         mInternalCleanupRunnable = internalCleanupRunnable;
@@ -127,7 +124,7 @@
 
     @Override
     public void serviceDied(long cookie) {
-        Slog.d(TAG, "HAL died.");
+        Slog.d(TAG, "Fingerprint HAL died.");
         mSession = null;
         mDaemon = null;
     }
@@ -139,12 +136,12 @@
     }
 
     @Override
-    public void init(GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
-            LockoutResetDispatcher lockoutResetDispatcher) {
+    public void init(@NonNull GestureAvailabilityDispatcher gestureAvailabilityDispatcher,
+            @NonNull LockoutResetDispatcher lockoutResetDispatcher) {
         setLazySession(this::getSession);
-        setScheduler(new UserAwareBiometricScheduler(TAG,
+        setScheduler(new BiometricScheduler<ISession, AidlSession>(getHandler(),
                 BiometricScheduler.sensorTypeFromFingerprintProperties(getSensorProperties()),
-                gestureAvailabilityDispatcher, () -> mCurrentUserId, getUserSwitchCallback()));
+                gestureAvailabilityDispatcher, () -> mCurrentUserId, getUserSwitchProvider()));
         mLockoutTracker = new LockoutFrameworkImpl(getContext(),
                 userId -> mLockoutResetDispatcher.notifyLockoutResetCallbacks(
                         getSensorProperties().sensorId));
@@ -152,6 +149,7 @@
 
     @Override
     @Nullable
+    @VisibleForTesting
     protected AidlSession getSessionForUser(int userId) {
         if (mSession != null && mSession.getUserId() == userId) {
             return mSession;
@@ -217,21 +215,18 @@
         }
 
         mDaemon.asBinder().linkToDeath(this, 0 /* flags */);
-
-        Slog.d(TAG, "Fingerprint HAL ready");
-
         scheduleLoadAuthenticatorIds();
         mInternalCleanupRunnable.run();
         return mDaemon;
     }
 
-    private UserAwareBiometricScheduler.UserSwitchCallback getUserSwitchCallback() {
-        return new UserAwareBiometricScheduler.UserSwitchCallback() {
+    private UserSwitchProvider<ISession, AidlSession> getUserSwitchProvider() {
+        return new UserSwitchProvider<>() {
             @NonNull
             @Override
-            public StopUserClient<?> getStopUserClient(int userId) {
-                return new StopUserClient<IBiometricsFingerprint>(getContext(),
-                        HidlToAidlSensorAdapter.this::getIBiometricsFingerprint,
+            public StopUserClient<AidlSession> getStopUserClient(int userId) {
+                return new StopUserClient<>(getContext(),
+                        HidlToAidlSensorAdapter.this::getSession,
                         null /* token */, userId, getSensorProperties().sensorId,
                         BiometricLogger.ofUnknown(getContext()), getBiometricContext(),
                         () -> {
@@ -258,7 +253,7 @@
 
             @NonNull
             @Override
-            public StartUserClient<?, ?> getStartUserClient(int newUserId) {
+            public StartUserClient<ISession, AidlSession> getStartUserClient(int newUserId) {
                 return getFingerprintUpdateActiveUserClient(newUserId,
                         false /* forceUpdateAuthenticatorId */);
             }
@@ -268,7 +263,7 @@
     private FingerprintUpdateActiveUserClient getFingerprintUpdateActiveUserClient(int newUserId,
             boolean forceUpdateAuthenticatorIds) {
         return new FingerprintUpdateActiveUserClient(getContext(),
-                this::getIBiometricsFingerprint, newUserId, TAG,
+                () -> getSession().getSession(), newUserId, TAG,
                 getSensorProperties().sensorId, BiometricLogger.ofUnknown(getContext()),
                 getBiometricContext(), () -> mCurrentUserId,
                 !FingerprintUtils.getInstance(getSensorProperties().sensorId)
@@ -290,7 +285,7 @@
     }
 
     @VisibleForTesting void handleUserChanged(int newUserId) {
-        Slog.d(TAG, "User changed. Current user is " + newUserId);
+        Slog.d(TAG, "User changed. Current user for fingerprint sensor is " + newUserId);
         mSession = null;
         mCurrentUserId = newUserId;
     }
diff --git a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSessionAdapter.java b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSessionAdapter.java
index 2fc00e1..b469752 100644
--- a/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSessionAdapter.java
+++ b/services/core/java/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSessionAdapter.java
@@ -209,6 +209,14 @@
         return null;
     }
 
+    public long getAuthenticatorIdForUpdateClient() throws RemoteException {
+        return mSession.get().getAuthenticatorId();
+    }
+
+    public void setActiveGroup(int userId, String absolutePath) throws RemoteException {
+        mSession.get().setActiveGroup(userId, absolutePath);
+    }
+
     private void setCallback(AidlResponseHandler aidlResponseHandler) {
         mHidlToAidlCallbackConverter = new HidlToAidlCallbackConverter(aidlResponseHandler);
         try {
diff --git a/services/tests/servicestests/src/com/android/server/biometrics/sensors/BiometricSchedulerTest.java b/services/tests/servicestests/src/com/android/server/biometrics/sensors/BiometricSchedulerTest.java
index 8929900..f7480de 100644
--- a/services/tests/servicestests/src/com/android/server/biometrics/sensors/BiometricSchedulerTest.java
+++ b/services/tests/servicestests/src/com/android/server/biometrics/sensors/BiometricSchedulerTest.java
@@ -44,12 +44,18 @@
 import android.hardware.biometrics.BiometricConstants;
 import android.hardware.biometrics.BiometricsProtoEnums;
 import android.hardware.biometrics.IBiometricService;
+import android.hardware.biometrics.fingerprint.IFingerprint;
+import android.hardware.biometrics.fingerprint.ISession;
 import android.hardware.fingerprint.Fingerprint;
 import android.os.Binder;
 import android.os.Handler;
 import android.os.IBinder;
 import android.os.RemoteException;
+import android.os.UserHandle;
 import android.platform.test.annotations.Presubmit;
+import android.platform.test.annotations.RequiresFlagsEnabled;
+import android.platform.test.flag.junit.CheckFlagsRule;
+import android.platform.test.flag.junit.DeviceFlagsValueProvider;
 import android.testing.AndroidTestingRunner;
 import android.testing.TestableContext;
 import android.testing.TestableLooper;
@@ -60,6 +66,7 @@
 import androidx.test.InstrumentationRegistry;
 import androidx.test.filters.SmallTest;
 
+import com.android.server.biometrics.Flags;
 import com.android.server.biometrics.log.BiometricContext;
 import com.android.server.biometrics.log.BiometricLogger;
 import com.android.server.biometrics.nano.BiometricSchedulerProto;
@@ -95,14 +102,39 @@
     @Rule
     public final TestableContext mContext = new TestableContext(
             InstrumentationRegistry.getContext(), null);
-    private BiometricScheduler mScheduler;
+    @Rule
+    public final CheckFlagsRule mCheckFlagsRule =
+            DeviceFlagsValueProvider.createCheckFlagsRule();
+    private BiometricScheduler<IFingerprint, ISession> mScheduler;
     private IBinder mToken;
+    private int mCurrentUserId = UserHandle.USER_SYSTEM;
+    private boolean mShouldFailStopUser = false;
+    private final List<Integer> mStartedUsers = new ArrayList<>();
+    private final StartUserClient.UserStartedCallback<ISession> mUserStartedCallback =
+            (newUserId, newUser, halInterfaceVersion) -> {
+                mStartedUsers.add(newUserId);
+                mCurrentUserId = newUserId;
+            };
+    private int mUsersStoppedCount = 0;
+    private final StopUserClient.UserStoppedCallback mUserStoppedCallback =
+            () -> {
+                mUsersStoppedCount++;
+                mCurrentUserId = UserHandle.USER_NULL;
+            };
+    private boolean mStartOperationsFinish = true;
+    private int mStartUserClientCount = 0;
     @Mock
     private IBiometricService mBiometricService;
     @Mock
     private BiometricContext mBiometricContext;
     @Mock
     private AuthSessionCoordinator mAuthSessionCoordinator;
+    @Mock
+    private BiometricLogger mBiometricLogger;
+    @Mock
+    private ISession mSession;
+    @Mock
+    private IFingerprint mFingerprint;
 
     @Before
     public void setUp() {
@@ -111,9 +143,39 @@
         when(mAuthSessionCoordinator.getLockoutStateFor(anyInt(), anyInt())).thenReturn(
                 BIOMETRIC_SUCCESS);
         when(mBiometricContext.getAuthSessionCoordinator()).thenReturn(mAuthSessionCoordinator);
-        mScheduler = new BiometricScheduler(TAG, new Handler(TestableLooper.get(this).getLooper()),
-                BiometricScheduler.SENSOR_TYPE_UNKNOWN, null /* gestureAvailabilityTracker */,
-                mBiometricService, LOG_NUM_RECENT_OPERATIONS);
+        if (Flags.deHidl()) {
+            mScheduler = new BiometricScheduler<>(
+                    new Handler(TestableLooper.get(this).getLooper()),
+                    BiometricScheduler.SENSOR_TYPE_UNKNOWN,
+                    null /* gestureAvailabilityDispatcher */,
+                    mBiometricService,
+                    LOG_NUM_RECENT_OPERATIONS,
+                    () -> mCurrentUserId,
+                    new UserSwitchProvider<IFingerprint, ISession>() {
+                        @NonNull
+                        @Override
+                        public StopUserClient<ISession> getStopUserClient(int userId) {
+                            return new TestStopUserClient(mContext, () -> mSession, mToken, userId,
+                                    TEST_SENSOR_ID, mBiometricLogger, mBiometricContext,
+                                    mUserStoppedCallback, () -> mShouldFailStopUser);
+                        }
+
+                        @NonNull
+                        @Override
+                        public StartUserClient<IFingerprint, ISession> getStartUserClient(
+                                int newUserId) {
+                            mStartUserClientCount++;
+                            return new TestStartUserClient(mContext, () -> mFingerprint, mToken,
+                                    newUserId, TEST_SENSOR_ID, mBiometricLogger, mBiometricContext,
+                                    mUserStartedCallback, mStartOperationsFinish);
+                        }
+                    });
+        } else {
+            mScheduler = new BiometricScheduler<>(
+                    new Handler(TestableLooper.get(this).getLooper()),
+                    BiometricScheduler.SENSOR_TYPE_UNKNOWN, null /* gestureAvailabilityTracker */,
+                    mBiometricService, LOG_NUM_RECENT_OPERATIONS);
+        }
     }
 
     @Test
@@ -479,6 +541,7 @@
         final boolean isEnroll = client instanceof TestEnrollClient;
 
         mScheduler.scheduleClientMonitor(client);
+        waitForIdle();
         if (started) {
             mScheduler.startPreparedClient(client.getCookie());
         }
@@ -789,6 +852,172 @@
         assertEquals(1,  client1.getFingerprints().size());
     }
 
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DE_HIDL)
+    public void testScheduleOperation_whenNoUser() {
+        mCurrentUserId = UserHandle.USER_NULL;
+
+        final BaseClientMonitor nextClient = mock(BaseClientMonitor.class);
+        when(nextClient.getTargetUserId()).thenReturn(0);
+
+        mScheduler.scheduleClientMonitor(nextClient);
+        waitForIdle();
+
+        assertThat(mUsersStoppedCount).isEqualTo(0);
+        assertThat(mStartedUsers).containsExactly(0);
+        verify(nextClient).start(any());
+    }
+
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DE_HIDL)
+    public void testScheduleOperation_whenNoUser_notStarted() {
+        mCurrentUserId = UserHandle.USER_NULL;
+        mStartOperationsFinish = false;
+
+        final BaseClientMonitor[] nextClients = new BaseClientMonitor[]{
+                mock(BaseClientMonitor.class),
+                mock(BaseClientMonitor.class),
+                mock(BaseClientMonitor.class)
+        };
+        for (BaseClientMonitor client : nextClients) {
+            when(client.getTargetUserId()).thenReturn(5);
+            mScheduler.scheduleClientMonitor(client);
+            waitForIdle();
+        }
+
+        assertThat(mUsersStoppedCount).isEqualTo(0);
+        assertThat(mStartedUsers).isEmpty();
+        assertThat(mStartUserClientCount).isEqualTo(1);
+        for (BaseClientMonitor client : nextClients) {
+            verify(client, never()).start(any());
+        }
+    }
+
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DE_HIDL)
+    public void testScheduleOperation_whenNoUser_notStarted_andReset() {
+        mCurrentUserId = UserHandle.USER_NULL;
+        mStartOperationsFinish = false;
+
+        final BaseClientMonitor client = mock(BaseClientMonitor.class);
+
+        when(client.getTargetUserId()).thenReturn(5);
+
+        mScheduler.scheduleClientMonitor(client);
+        waitForIdle();
+
+        final TestStartUserClient startUserClient =
+                (TestStartUserClient) mScheduler.mCurrentOperation.getClientMonitor();
+        mScheduler.reset();
+
+        assertThat(mScheduler.mCurrentOperation).isNull();
+
+        final BiometricSchedulerOperation fakeOperation = new BiometricSchedulerOperation(
+                mock(BaseClientMonitor.class), new ClientMonitorCallback() {});
+        mScheduler.mCurrentOperation = fakeOperation;
+        startUserClient.mCallback.onClientFinished(startUserClient, true);
+
+        assertThat(fakeOperation).isSameInstanceAs(mScheduler.mCurrentOperation);
+    }
+
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DE_HIDL)
+    public void testScheduleOperation_whenSameUser() {
+        mCurrentUserId = 10;
+
+        BaseClientMonitor nextClient = mock(BaseClientMonitor.class);
+        when(nextClient.getTargetUserId()).thenReturn(mCurrentUserId);
+
+        mScheduler.scheduleClientMonitor(nextClient);
+
+        waitForIdle();
+
+        verify(nextClient).start(any());
+        assertThat(mUsersStoppedCount).isEqualTo(0);
+        assertThat(mStartedUsers).isEmpty();
+    }
+
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DE_HIDL)
+    public void testScheduleOperation_whenDifferentUser() {
+        mCurrentUserId = 10;
+
+        final int nextUserId = 11;
+        BaseClientMonitor nextClient = mock(BaseClientMonitor.class);
+        when(nextClient.getTargetUserId()).thenReturn(nextUserId);
+
+        mScheduler.scheduleClientMonitor(nextClient);
+
+        waitForIdle();
+        assertThat(mUsersStoppedCount).isEqualTo(1);
+
+        waitForIdle();
+        assertThat(mStartedUsers).containsExactly(nextUserId);
+
+        waitForIdle();
+        verify(nextClient).start(any());
+    }
+
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DE_HIDL)
+    public void testStartUser_alwaysStartsNextOperation() {
+        mCurrentUserId = UserHandle.USER_NULL;
+
+        BaseClientMonitor nextClient = mock(BaseClientMonitor.class);
+        when(nextClient.getTargetUserId()).thenReturn(10);
+
+        mScheduler.scheduleClientMonitor(nextClient);
+
+        waitForIdle();
+        verify(nextClient).start(any());
+
+        // finish first operation
+        mScheduler.getInternalCallback().onClientFinished(nextClient, true /* success */);
+        waitForIdle();
+
+        // schedule second operation but swap out the current operation
+        // before it runs so that it's not current when it's completion callback runs
+        nextClient = mock(BaseClientMonitor.class);
+        when(nextClient.getTargetUserId()).thenReturn(11);
+        mScheduler.scheduleClientMonitor(nextClient);
+
+        waitForIdle();
+        verify(nextClient).start(any());
+        assertThat(mStartedUsers).containsExactly(10, 11).inOrder();
+        assertThat(mUsersStoppedCount).isEqualTo(1);
+    }
+
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_DE_HIDL)
+    public void testStartUser_failsClearsStopUserClient() {
+        mCurrentUserId = UserHandle.USER_NULL;
+
+        // When a stop user client fails, check that mStopUserClient
+        // is set to null to prevent the scheduler from getting stuck.
+        BaseClientMonitor nextClient = mock(BaseClientMonitor.class);
+        when(nextClient.getTargetUserId()).thenReturn(10);
+
+        mScheduler.scheduleClientMonitor(nextClient);
+
+        waitForIdle();
+        verify(nextClient).start(any());
+
+        // finish first operation
+        mScheduler.getInternalCallback().onClientFinished(nextClient, true /* success */);
+        waitForIdle();
+
+        // schedule second operation but swap out the current operation
+        // before it runs so that it's not current when it's completion callback runs
+        nextClient = mock(BaseClientMonitor.class);
+        when(nextClient.getTargetUserId()).thenReturn(11);
+        mShouldFailStopUser = true;
+        mScheduler.scheduleClientMonitor(nextClient);
+
+        waitForIdle();
+        assertThat(mStartedUsers).containsExactly(10, 11).inOrder();
+        assertThat(mUsersStoppedCount).isEqualTo(0);
+        assertThat(mScheduler.getStopUserClient()).isEqualTo(null);
+    }
 
     private BiometricSchedulerProto getDump(boolean clearSchedulerBuffer) throws Exception {
         return BiometricSchedulerProto.parseFrom(mScheduler.dumpProtoState(clearSchedulerBuffer));
@@ -1069,4 +1298,82 @@
             return mFingerprints;
         }
     }
+
+    private interface StopUserClientShouldFail {
+        boolean shouldFail();
+    }
+
+    private class TestStopUserClient extends StopUserClient<ISession> {
+        private StopUserClientShouldFail mShouldFailClient;
+        TestStopUserClient(@NonNull Context context,
+                @NonNull Supplier<ISession> lazyDaemon, @Nullable IBinder token, int userId,
+                int sensorId, @NonNull BiometricLogger logger,
+                @NonNull BiometricContext biometricContext,
+                @NonNull UserStoppedCallback callback, StopUserClientShouldFail shouldFail) {
+            super(context, lazyDaemon, token, userId, sensorId, logger, biometricContext, callback);
+            mShouldFailClient = shouldFail;
+        }
+
+        @Override
+        protected void startHalOperation() {
+
+        }
+
+        @Override
+        public void start(@NonNull ClientMonitorCallback callback) {
+            super.start(callback);
+            if (mShouldFailClient.shouldFail()) {
+                getCallback().onClientFinished(this, false /* success */);
+                // When the above fails, it means that the HAL has died, in this case we
+                // need to ensure the UserSwitchCallback correctly returns the NULL user handle.
+                mCurrentUserId = UserHandle.USER_NULL;
+            } else {
+                onUserStopped();
+            }
+        }
+
+        @Override
+        public void unableToStart() {
+
+        }
+    }
+
+    private static class TestStartUserClient extends StartUserClient<IFingerprint, ISession> {
+
+        @Mock
+        private ISession mSession;
+        private final boolean mShouldFinish;
+        ClientMonitorCallback mCallback;
+
+        TestStartUserClient(@NonNull Context context,
+                @NonNull Supplier<IFingerprint> lazyDaemon, @Nullable IBinder token, int userId,
+                int sensorId, @NonNull BiometricLogger logger,
+                @NonNull BiometricContext biometricContext,
+                @NonNull UserStartedCallback<ISession> callback, boolean shouldFinish) {
+            super(context, lazyDaemon, token, userId, sensorId, logger, biometricContext, callback);
+            mShouldFinish = shouldFinish;
+        }
+
+        @Override
+        protected void startHalOperation() {
+
+        }
+
+        @Override
+        public void start(@NonNull ClientMonitorCallback callback) {
+            super.start(callback);
+
+            mCallback = callback;
+            if (mShouldFinish) {
+                mUserStartedCallback.onUserStarted(
+                        getTargetUserId(), mSession, 1 /* halInterfaceVersion */);
+                callback.onClientFinished(this, true /* success */);
+            }
+        }
+
+        @Override
+        public void unableToStart() {
+
+        }
+    }
 }
diff --git a/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/aidl/FaceProviderTest.java b/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/aidl/FaceProviderTest.java
index 8b1a291..772ec8b 100644
--- a/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/aidl/FaceProviderTest.java
+++ b/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/aidl/FaceProviderTest.java
@@ -36,8 +36,10 @@
 import android.hardware.biometrics.face.ISession;
 import android.hardware.biometrics.face.SensorProps;
 import android.hardware.face.HidlFaceSensorConfig;
+import android.os.Handler;
 import android.os.RemoteException;
 import android.os.UserManager;
+import android.os.test.TestLooper;
 import android.platform.test.annotations.Presubmit;
 import android.platform.test.annotations.RequiresFlagsEnabled;
 import android.platform.test.flag.junit.CheckFlagsRule;
@@ -88,14 +90,11 @@
     @Mock
     private BiometricStateCallback mBiometricStateCallback;
 
+    private final TestLooper mLooper = new TestLooper();
     private SensorProps[] mSensorProps;
     private LockoutResetDispatcher mLockoutResetDispatcher;
     private FaceProvider mFaceProvider;
 
-    private static void waitForIdle() {
-        InstrumentationRegistry.getInstrumentation().waitForIdleSync();
-    }
-
     @Before
     public void setUp() throws RemoteException {
         MockitoAnnotations.initMocks(this);
@@ -121,7 +120,8 @@
 
         mFaceProvider = new FaceProvider(mContext, mBiometricStateCallback,
                 mSensorProps, TAG, mLockoutResetDispatcher, mBiometricContext,
-                mDaemon, false /* resetLockoutRequiresChallenge */, false /* testHalEnabled */);
+                mDaemon, new Handler(mLooper.getLooper()),
+                false /* resetLockoutRequiresChallenge */, false /* testHalEnabled */);
     }
 
     @Test
@@ -156,6 +156,7 @@
         mFaceProvider = new FaceProvider(mContext,
                 mBiometricStateCallback, hidlFaceSensorConfig, TAG,
                 mLockoutResetDispatcher, mBiometricContext, mDaemon,
+                new Handler(mLooper.getLooper()),
                 true /* resetLockoutRequiresChallenge */,
                 true /* testHalEnabled */);
 
@@ -210,4 +211,12 @@
             assertEquals(0, scheduler.getCurrentPendingCount());
         }
     }
+
+    private void waitForIdle() {
+        if (Flags.deHidl()) {
+            mLooper.dispatchAll();
+        } else {
+            InstrumentationRegistry.getInstrumentation().waitForIdleSync();
+        }
+    }
 }
diff --git a/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/aidl/SensorTest.java b/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/aidl/SensorTest.java
index e7f7195..fe9cd43 100644
--- a/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/aidl/SensorTest.java
+++ b/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/aidl/SensorTest.java
@@ -31,6 +31,7 @@
 import android.content.Context;
 import android.hardware.biometrics.IBiometricService;
 import android.hardware.biometrics.common.CommonProps;
+import android.hardware.biometrics.face.IFace;
 import android.hardware.biometrics.face.ISession;
 import android.hardware.biometrics.face.SensorProps;
 import android.hardware.face.FaceSensorPropertiesInternal;
@@ -40,6 +41,7 @@
 
 import androidx.test.filters.SmallTest;
 
+import com.android.server.biometrics.Flags;
 import com.android.server.biometrics.log.BiometricContext;
 import com.android.server.biometrics.log.BiometricLogger;
 import com.android.server.biometrics.sensors.AuthSessionCoordinator;
@@ -49,6 +51,7 @@
 import com.android.server.biometrics.sensors.LockoutResetDispatcher;
 import com.android.server.biometrics.sensors.LockoutTracker;
 import com.android.server.biometrics.sensors.UserAwareBiometricScheduler;
+import com.android.server.biometrics.sensors.UserSwitchProvider;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -74,6 +77,8 @@
     @Mock
     private UserAwareBiometricScheduler.UserSwitchCallback mUserSwitchCallback;
     @Mock
+    private UserSwitchProvider<IFace, ISession> mUserSwitchProvider;
+    @Mock
     private AidlResponseHandler.HardwareUnavailableCallback mHardwareUnavailableCallback;
     @Mock
     private LockoutResetDispatcher mLockoutResetDispatcher;
@@ -84,16 +89,16 @@
     @Mock
     private AuthSessionCoordinator mAuthSessionCoordinator;
     @Mock
-    FaceProvider mFaceProvider;
+    private FaceProvider mFaceProvider;
     @Mock
-    BaseClientMonitor mClientMonitor;
+    private BaseClientMonitor mClientMonitor;
     @Mock
-    AidlSession mCurrentSession;
+    private AidlSession mCurrentSession;
 
     private final TestLooper mLooper = new TestLooper();
     private final LockoutCache mLockoutCache = new LockoutCache();
 
-    private UserAwareBiometricScheduler mScheduler;
+    private BiometricScheduler<IFace, ISession> mScheduler;
     private AidlResponseHandler mHalCallback;
 
     @Before
@@ -101,16 +106,26 @@
         MockitoAnnotations.initMocks(this);
 
         when(mContext.getSystemService(Context.BIOMETRIC_SERVICE)).thenReturn(mBiometricService);
-
         when(mBiometricContext.getAuthSessionCoordinator()).thenReturn(mAuthSessionCoordinator);
 
-        mScheduler = new UserAwareBiometricScheduler(TAG,
-                new Handler(mLooper.getLooper()),
-                BiometricScheduler.SENSOR_TYPE_FACE,
-                null /* gestureAvailabilityDispatcher */,
-                mBiometricService,
-                () -> USER_ID,
-                mUserSwitchCallback);
+        if (Flags.deHidl()) {
+            mScheduler = new BiometricScheduler<>(
+                    new Handler(mLooper.getLooper()),
+                    BiometricScheduler.SENSOR_TYPE_FACE,
+                    null /* gestureAvailabilityDispatcher */,
+                    mBiometricService,
+                    2 /* recentOperationsLimit */,
+                    () -> USER_ID,
+                    mUserSwitchProvider);
+        } else {
+            mScheduler = new UserAwareBiometricScheduler<>(TAG,
+                    new Handler(mLooper.getLooper()),
+                    BiometricScheduler.SENSOR_TYPE_FACE,
+                    null /* gestureAvailabilityDispatcher */,
+                    mBiometricService,
+                    () -> USER_ID,
+                    mUserSwitchCallback);
+        }
         mHalCallback = new AidlResponseHandler(mContext, mScheduler, SENSOR_ID, USER_ID,
                 mLockoutCache, mLockoutResetDispatcher, mAuthSessionCoordinator,
                 mHardwareUnavailableCallback);
@@ -146,18 +161,8 @@
     @Test
     public void onBinderDied_noErrorOnNullClient() {
         mLooper.dispatchAll();
-
-        final SensorProps sensorProps = new SensorProps();
-        sensorProps.commonProps = new CommonProps();
-        sensorProps.commonProps.sensorId = 1;
-        final FaceSensorPropertiesInternal internalProp = new FaceSensorPropertiesInternal(
-                sensorProps.commonProps.sensorId, sensorProps.commonProps.sensorStrength,
-                sensorProps.commonProps.maxEnrollmentsPerUser, null /* componentInfo */,
-                sensorProps.sensorType, sensorProps.supportsDetectInteraction,
-                sensorProps.halControlsPreview, false /* resetLockoutRequiresChallenge */);
-        final Sensor sensor = new Sensor("SensorTest", mFaceProvider, mContext,
-                null /* handler */, internalProp, mLockoutResetDispatcher, mBiometricContext);
-        sensor.init(mLockoutResetDispatcher, mFaceProvider);
+        final Sensor sensor = getSensor();
+        mScheduler = sensor.getScheduler();
         mScheduler.reset();
 
         assertNull(mScheduler.getCurrentClient());
@@ -175,18 +180,8 @@
         when(mClientMonitor.getTargetUserId()).thenReturn(USER_ID);
         when(mClientMonitor.isInterruptable()).thenReturn(false);
 
-        final SensorProps sensorProps = new SensorProps();
-        sensorProps.commonProps = new CommonProps();
-        sensorProps.commonProps.sensorId = 1;
-        final FaceSensorPropertiesInternal internalProp = new FaceSensorPropertiesInternal(
-                sensorProps.commonProps.sensorId, sensorProps.commonProps.sensorStrength,
-                sensorProps.commonProps.maxEnrollmentsPerUser, null /* componentInfo */,
-                sensorProps.sensorType, sensorProps.supportsDetectInteraction,
-                sensorProps.halControlsPreview, false /* resetLockoutRequiresChallenge */);
-        final Sensor sensor = new Sensor("SensorTest", mFaceProvider, mContext, null,
-                internalProp, mLockoutResetDispatcher, mBiometricContext, mCurrentSession);
-        sensor.init(mLockoutResetDispatcher, mFaceProvider);
-        mScheduler = (UserAwareBiometricScheduler) sensor.getScheduler();
+        final Sensor sensor = getSensor();
+        mScheduler = sensor.getScheduler();
         sensor.mCurrentSession = new AidlSession(0, mock(ISession.class),
                 USER_ID, mHalCallback);
 
@@ -206,4 +201,20 @@
         verify(mLockoutResetDispatcher).notifyLockoutResetCallbacks(eq(SENSOR_ID));
         verify(mAuthSessionCoordinator).resetLockoutFor(eq(USER_ID), anyInt(), anyLong());
     }
+
+    private Sensor getSensor() {
+        final SensorProps sensorProps = new SensorProps();
+        sensorProps.commonProps = new CommonProps();
+        sensorProps.commonProps.sensorId = 1;
+        final FaceSensorPropertiesInternal internalProp = new FaceSensorPropertiesInternal(
+                sensorProps.commonProps.sensorId, sensorProps.commonProps.sensorStrength,
+                sensorProps.commonProps.maxEnrollmentsPerUser, null /* componentInfo */,
+                sensorProps.sensorType, sensorProps.supportsDetectInteraction,
+                sensorProps.halControlsPreview, false /* resetLockoutRequiresChallenge */);
+        final Sensor sensor = new Sensor(mFaceProvider, mContext,
+                null /* handler */, internalProp, mBiometricContext);
+        sensor.init(mLockoutResetDispatcher, mFaceProvider);
+
+        return sensor;
+    }
 }
diff --git a/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSensorAdapterTest.java b/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSensorAdapterTest.java
index 4e43332..940fe69 100644
--- a/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSensorAdapterTest.java
+++ b/services/tests/servicestests/src/com/android/server/biometrics/sensors/face/hidl/HidlToAidlSensorAdapterTest.java
@@ -45,7 +45,6 @@
 import com.android.server.biometrics.log.BiometricContext;
 import com.android.server.biometrics.log.BiometricLogger;
 import com.android.server.biometrics.sensors.AuthSessionCoordinator;
-import com.android.server.biometrics.sensors.BiometricScheduler;
 import com.android.server.biometrics.sensors.BiometricUtils;
 import com.android.server.biometrics.sensors.LockoutResetDispatcher;
 import com.android.server.biometrics.sensors.LockoutTracker;
@@ -88,9 +87,9 @@
     @Mock
     private IBiometricsFace mDaemon;
     @Mock
-    AidlResponseHandler.AidlResponseHandlerCallback mAidlResponseHandlerCallback;
+    private AidlResponseHandler.AidlResponseHandlerCallback mAidlResponseHandlerCallback;
     @Mock
-    BiometricUtils<Face> mBiometricUtils;
+    private BiometricUtils<Face> mBiometricUtils;
 
     private final TestLooper mLooper = new TestLooper();
     private HidlToAidlSensorAdapter mHidlToAidlSensorAdapter;
@@ -118,20 +117,14 @@
         mContext.getOrCreateTestableResources();
 
         final String config = String.format("%d:8:15", SENSOR_ID);
-        final BiometricScheduler scheduler = new BiometricScheduler(TAG,
-                new Handler(mLooper.getLooper()),
-                BiometricScheduler.SENSOR_TYPE_FACE,
-                null /* gestureAvailabilityTracker */,
-                mBiometricService, 10 /* recentOperationsLimit */);
         final HidlFaceSensorConfig faceSensorConfig = new HidlFaceSensorConfig();
         faceSensorConfig.parse(config, mContext);
-        mHidlToAidlSensorAdapter = new HidlToAidlSensorAdapter(TAG, mFaceProvider,
+        mHidlToAidlSensorAdapter = new HidlToAidlSensorAdapter(mFaceProvider,
                 mContext, new Handler(mLooper.getLooper()), faceSensorConfig,
                 mLockoutResetDispatcherForSensor, mBiometricContext,
                 false /* resetLockoutRequiresChallenge */, mInternalCleanupAndGetFeatureRunnable,
                 mAuthSessionCoordinator, mDaemon, mAidlResponseHandlerCallback);
         mHidlToAidlSensorAdapter.init(mLockoutResetDispatcherForSensor, mFaceProvider);
-        mHidlToAidlSensorAdapter.setScheduler(scheduler);
         mHidlToAidlSensorAdapter.handleUserChanged(USER_ID);
     }
 
diff --git a/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintProviderTest.java b/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintProviderTest.java
index bf5986c..258be57 100644
--- a/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintProviderTest.java
+++ b/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/aidl/FingerprintProviderTest.java
@@ -38,8 +38,10 @@
 import android.hardware.biometrics.fingerprint.SensorLocation;
 import android.hardware.biometrics.fingerprint.SensorProps;
 import android.hardware.fingerprint.HidlFingerprintSensorConfig;
+import android.os.Handler;
 import android.os.RemoteException;
 import android.os.UserManager;
+import android.os.test.TestLooper;
 import android.platform.test.annotations.Presubmit;
 import android.platform.test.annotations.RequiresFlagsEnabled;
 import android.platform.test.flag.junit.CheckFlagsRule;
@@ -92,14 +94,12 @@
     @Mock
     private BiometricContext mBiometricContext;
 
+    private final TestLooper mLooper = new TestLooper();
+
     private SensorProps[] mSensorProps;
     private LockoutResetDispatcher mLockoutResetDispatcher;
     private FingerprintProvider mFingerprintProvider;
 
-    private static void waitForIdle() {
-        InstrumentationRegistry.getInstrumentation().waitForIdleSync();
-    }
-
     @Before
     public void setUp() throws RemoteException {
         MockitoAnnotations.initMocks(this);
@@ -126,7 +126,8 @@
         mFingerprintProvider = new FingerprintProvider(mContext,
                 mBiometricStateCallback, mAuthenticationStateListeners, mSensorProps, TAG,
                 mLockoutResetDispatcher, mGestureAvailabilityDispatcher, mBiometricContext,
-                mDaemon, false /* resetLockoutRequiresHardwareAuthToken */,
+                mDaemon, new Handler(mLooper.getLooper()),
+                false /* resetLockoutRequiresHardwareAuthToken */,
                 true /* testHalEnabled */);
     }
 
@@ -159,6 +160,7 @@
                 mBiometricStateCallback, mAuthenticationStateListeners,
                 hidlFingerprintSensorConfigs, TAG, mLockoutResetDispatcher,
                 mGestureAvailabilityDispatcher, mBiometricContext, mDaemon,
+                new Handler(mLooper.getLooper()),
                 false /* resetLockoutRequiresHardwareAuthToken */,
                 true /* testHalEnabled */);
 
@@ -215,4 +217,12 @@
             assertEquals(0, scheduler.getCurrentPendingCount());
         }
     }
+
+    private void waitForIdle() {
+        if (Flags.deHidl()) {
+            mLooper.dispatchAll();
+        } else {
+            InstrumentationRegistry.getInstrumentation().waitForIdleSync();
+        }
+    }
 }
diff --git a/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/aidl/SensorTest.java b/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/aidl/SensorTest.java
index 126a05e..b4c2ee8 100644
--- a/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/aidl/SensorTest.java
+++ b/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/aidl/SensorTest.java
@@ -32,14 +32,17 @@
 import android.hardware.biometrics.IBiometricService;
 import android.hardware.biometrics.common.CommonProps;
 import android.hardware.biometrics.face.SensorProps;
+import android.hardware.biometrics.fingerprint.IFingerprint;
 import android.hardware.biometrics.fingerprint.ISession;
 import android.hardware.fingerprint.FingerprintSensorPropertiesInternal;
 import android.os.Handler;
+import android.os.HandlerThread;
 import android.os.test.TestLooper;
 import android.platform.test.annotations.Presubmit;
 
 import androidx.test.filters.SmallTest;
 
+import com.android.server.biometrics.Flags;
 import com.android.server.biometrics.log.BiometricContext;
 import com.android.server.biometrics.log.BiometricLogger;
 import com.android.server.biometrics.sensors.AuthSessionCoordinator;
@@ -49,6 +52,7 @@
 import com.android.server.biometrics.sensors.LockoutResetDispatcher;
 import com.android.server.biometrics.sensors.LockoutTracker;
 import com.android.server.biometrics.sensors.UserAwareBiometricScheduler;
+import com.android.server.biometrics.sensors.UserSwitchProvider;
 import com.android.server.biometrics.sensors.fingerprint.GestureAvailabilityDispatcher;
 
 import org.junit.Before;
@@ -75,6 +79,8 @@
     @Mock
     private UserAwareBiometricScheduler.UserSwitchCallback mUserSwitchCallback;
     @Mock
+    private UserSwitchProvider<IFingerprint, ISession> mUserSwitchProvider;
+    @Mock
     private AidlResponseHandler.HardwareUnavailableCallback mHardwareUnavailableCallback;
     @Mock
     private LockoutResetDispatcher mLockoutResetDispatcher;
@@ -92,11 +98,13 @@
     private AidlSession mCurrentSession;
     @Mock
     private BaseClientMonitor mClientMonitor;
+    @Mock
+    private HandlerThread mThread;
 
     private final TestLooper mLooper = new TestLooper();
     private final LockoutCache mLockoutCache = new LockoutCache();
 
-    private BiometricScheduler mScheduler;
+    private BiometricScheduler<IFingerprint, ISession> mScheduler;
     private AidlResponseHandler mHalCallback;
 
     @Before
@@ -105,14 +113,26 @@
 
         when(mContext.getSystemService(Context.BIOMETRIC_SERVICE)).thenReturn(mBiometricService);
         when(mBiometricContext.getAuthSessionCoordinator()).thenReturn(mAuthSessionCoordinator);
+        when(mThread.getLooper()).thenReturn(mLooper.getLooper());
 
-        mScheduler = new UserAwareBiometricScheduler(TAG,
-                new Handler(mLooper.getLooper()),
-                BiometricScheduler.SENSOR_TYPE_FP_OTHER,
-                null /* gestureAvailabilityDispatcher */,
-                mBiometricService,
-                () -> USER_ID,
-                mUserSwitchCallback);
+        if (Flags.deHidl()) {
+            mScheduler = new BiometricScheduler<>(
+                    new Handler(mLooper.getLooper()),
+                    BiometricScheduler.SENSOR_TYPE_FP_OTHER,
+                    null /* gestureAvailabilityDispatcher */,
+                    mBiometricService,
+                    2 /* recentOperationsLimit */,
+                    () -> USER_ID,
+                    mUserSwitchProvider);
+        } else {
+            mScheduler = new UserAwareBiometricScheduler<>(TAG,
+                    new Handler(mLooper.getLooper()),
+                    BiometricScheduler.SENSOR_TYPE_FP_OTHER,
+                    null /* gestureAvailabilityDispatcher */,
+                    mBiometricService,
+                    () -> USER_ID,
+                    mUserSwitchCallback);
+        }
         mHalCallback = new AidlResponseHandler(mContext, mScheduler, SENSOR_ID, USER_ID,
                 mLockoutCache, mLockoutResetDispatcher, mAuthSessionCoordinator,
                 mHardwareUnavailableCallback);
@@ -153,18 +173,7 @@
         when(mClientMonitor.getTargetUserId()).thenReturn(USER_ID);
         when(mClientMonitor.isInterruptable()).thenReturn(false);
 
-        final SensorProps sensorProps = new SensorProps();
-        sensorProps.commonProps = new CommonProps();
-        sensorProps.commonProps.sensorId = 1;
-        final FingerprintSensorPropertiesInternal internalProp = new
-                FingerprintSensorPropertiesInternal(
-                        sensorProps.commonProps.sensorId, sensorProps.commonProps.sensorStrength,
-                        sensorProps.commonProps.maxEnrollmentsPerUser, null,
-                        sensorProps.sensorType, false /* resetLockoutRequiresHardwareAuthToken */);
-        final Sensor sensor = new Sensor("SensorTest", mFingerprintProvider, mContext,
-                null /* handler */, internalProp, mLockoutResetDispatcher,
-                mGestureAvailabilityDispatcher, mBiometricContext, mCurrentSession);
-        sensor.init(mGestureAvailabilityDispatcher, mLockoutResetDispatcher);
+        final Sensor sensor = getSensor();
         mScheduler = sensor.getScheduler();
         sensor.mCurrentSession = new AidlSession(0, mock(ISession.class),
                 USER_ID, mHalCallback);
@@ -185,4 +194,21 @@
         verify(mLockoutResetDispatcher).notifyLockoutResetCallbacks(eq(SENSOR_ID));
         verify(mAuthSessionCoordinator).resetLockoutFor(eq(USER_ID), anyInt(), anyLong());
     }
+
+    private Sensor getSensor() {
+        final SensorProps sensorProps = new SensorProps();
+        sensorProps.commonProps = new CommonProps();
+        sensorProps.commonProps.sensorId = 1;
+        final FingerprintSensorPropertiesInternal internalProp = new
+                FingerprintSensorPropertiesInternal(
+                sensorProps.commonProps.sensorId, sensorProps.commonProps.sensorStrength,
+                sensorProps.commonProps.maxEnrollmentsPerUser, null,
+                sensorProps.sensorType, false /* resetLockoutRequiresHardwareAuthToken */);
+        final Sensor sensor = new Sensor(mFingerprintProvider, mContext,
+                null /* handler */, internalProp,
+                mBiometricContext, mCurrentSession);
+        sensor.init(mGestureAvailabilityDispatcher, mLockoutResetDispatcher);
+
+        return sensor;
+    }
 }
diff --git a/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSensorAdapterTest.java b/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSensorAdapterTest.java
index 59c94dc..01175e8 100644
--- a/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSensorAdapterTest.java
+++ b/services/tests/servicestests/src/com/android/server/biometrics/sensors/fingerprint/hidl/HidlToAidlSensorAdapterTest.java
@@ -36,12 +36,12 @@
 import android.hardware.fingerprint.Fingerprint;
 import android.hardware.fingerprint.HidlFingerprintSensorConfig;
 import android.os.Handler;
+import android.os.HandlerThread;
 import android.os.RemoteException;
 import android.os.test.TestLooper;
 import android.platform.test.annotations.Presubmit;
 import android.testing.TestableContext;
 
-import androidx.annotation.NonNull;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.filters.SmallTest;
 
@@ -49,17 +49,11 @@
 import com.android.server.biometrics.log.BiometricLogger;
 import com.android.server.biometrics.sensors.AuthSessionCoordinator;
 import com.android.server.biometrics.sensors.AuthenticationStateListeners;
-import com.android.server.biometrics.sensors.BiometricScheduler;
 import com.android.server.biometrics.sensors.BiometricUtils;
-import com.android.server.biometrics.sensors.ClientMonitorCallback;
 import com.android.server.biometrics.sensors.LockoutResetDispatcher;
 import com.android.server.biometrics.sensors.LockoutTracker;
-import com.android.server.biometrics.sensors.StartUserClient;
-import com.android.server.biometrics.sensors.StopUserClient;
-import com.android.server.biometrics.sensors.UserAwareBiometricScheduler;
 import com.android.server.biometrics.sensors.fingerprint.GestureAvailabilityDispatcher;
 import com.android.server.biometrics.sensors.fingerprint.aidl.AidlResponseHandler;
-import com.android.server.biometrics.sensors.fingerprint.aidl.AidlSession;
 import com.android.server.biometrics.sensors.fingerprint.aidl.FingerprintEnrollClient;
 import com.android.server.biometrics.sensors.fingerprint.aidl.FingerprintProvider;
 import com.android.server.biometrics.sensors.fingerprint.aidl.FingerprintResetLockoutClient;
@@ -112,60 +106,18 @@
     private BiometricUtils<Fingerprint> mBiometricUtils;
     @Mock
     private AuthenticationStateListeners mAuthenticationStateListeners;
+    @Mock
+    private HandlerThread mThread;
 
     private final TestLooper mLooper = new TestLooper();
     private HidlToAidlSensorAdapter mHidlToAidlSensorAdapter;
     private final TestableContext mContext = new TestableContext(
             ApplicationProvider.getApplicationContext());
 
-    private final UserAwareBiometricScheduler.UserSwitchCallback mUserSwitchCallback =
-            new UserAwareBiometricScheduler.UserSwitchCallback() {
-                @NonNull
-                @Override
-                public StopUserClient<?> getStopUserClient(int userId) {
-                    return new StopUserClient<IBiometricsFingerprint>(mContext,
-                            mHidlToAidlSensorAdapter::getIBiometricsFingerprint, null, USER_ID,
-                            SENSOR_ID, mLogger, mBiometricContext, () -> {}) {
-                        @Override
-                        protected void startHalOperation() {
-                            getCallback().onClientFinished(this, true /* success */);
-                        }
-
-                        @Override
-                        public void unableToStart() {}
-                    };
-                }
-
-                @NonNull
-                @Override
-                public StartUserClient<?, ?> getStartUserClient(int newUserId) {
-                    return new StartUserClient<IBiometricsFingerprint, AidlSession>(mContext,
-                            mHidlToAidlSensorAdapter::getIBiometricsFingerprint, null,
-                            USER_ID, SENSOR_ID,
-                            mLogger, mBiometricContext,
-                            (newUserId1, newUser, halInterfaceVersion) ->
-                                    mHidlToAidlSensorAdapter.handleUserChanged(newUserId1)) {
-                        @Override
-                        public void start(@NonNull ClientMonitorCallback callback) {
-                            super.start(callback);
-                            startHalOperation();
-                        }
-
-                        @Override
-                        protected void startHalOperation() {
-                            mUserStartedCallback.onUserStarted(USER_ID, null, 0);
-                            getCallback().onClientFinished(this, true /* success */);
-                        }
-
-                        @Override
-                        public void unableToStart() {}
-                    };
-                }
-            };;
-
     @Before
     public void setUp() throws RemoteException {
         when(mBiometricContext.getAuthSessionCoordinator()).thenReturn(mAuthSessionCoordinator);
+        when(mThread.getLooper()).thenReturn(mLooper.getLooper());
         doAnswer((answer) -> {
             mHidlToAidlSensorAdapter.getLazySession().get().getHalSessionCallback()
                     .onEnrollmentProgress(1 /* enrollmentId */, 0 /* remaining */);
@@ -176,26 +128,18 @@
         mContext.getOrCreateTestableResources();
 
         final String config = String.format("%d:2:15", SENSOR_ID);
-        final UserAwareBiometricScheduler scheduler = new UserAwareBiometricScheduler(TAG,
-                new Handler(mLooper.getLooper()),
-                BiometricScheduler.SENSOR_TYPE_FP_OTHER,
-                null /* gestureAvailabilityDispatcher */,
-                mBiometricService,
-                () -> USER_ID,
-                mUserSwitchCallback);
         final HidlFingerprintSensorConfig fingerprintSensorConfig =
                 new HidlFingerprintSensorConfig();
         fingerprintSensorConfig.parse(config, mContext);
-        mHidlToAidlSensorAdapter = new HidlToAidlSensorAdapter(TAG,
+        mHidlToAidlSensorAdapter = new HidlToAidlSensorAdapter(
                 mFingerprintProvider, mContext, new Handler(mLooper.getLooper()),
                 fingerprintSensorConfig, mLockoutResetDispatcherForSensor,
-                mGestureAvailabilityDispatcher, mBiometricContext,
-                false /* resetLockoutRequiresHardwareAuthToken */,
+                mBiometricContext, false /* resetLockoutRequiresHardwareAuthToken */,
                 mInternalCleanupRunnable, mAuthSessionCoordinator, mDaemon,
                 mAidlResponseHandlerCallback);
         mHidlToAidlSensorAdapter.init(mGestureAvailabilityDispatcher,
                 mLockoutResetDispatcherForSensor);
-        mHidlToAidlSensorAdapter.setScheduler(scheduler);
+
         mHidlToAidlSensorAdapter.handleUserChanged(USER_ID);
     }