diff --git a/media/libaudiohal/impl/DevicesFactoryHalHidl.cpp b/media/libaudiohal/impl/DevicesFactoryHalHidl.cpp
index e6e9688..1c0eacb 100644
--- a/media/libaudiohal/impl/DevicesFactoryHalHidl.cpp
+++ b/media/libaudiohal/impl/DevicesFactoryHalHidl.cpp
@@ -15,12 +15,13 @@
  */
 
 #include <string.h>
-#include <vector>
+#include <set>
 
 #define LOG_TAG "DevicesFactoryHalHidl"
 //#define LOG_NDEBUG 0
 
 #include <android/hidl/manager/1.0/IServiceManager.h>
+#include <android/hidl/manager/1.0/IServiceNotification.h>
 #include PATH(android/hardware/audio/FILE_VERSION/IDevice.h)
 #include <media/audiohal/hidl/HalDeathHandler.h>
 #include <utils/Log.h>
@@ -29,33 +30,57 @@
 #include "DeviceHalHidl.h"
 #include "DevicesFactoryHalHidl.h"
 
-#include <set>
-
 using ::android::hardware::audio::CPP_VERSION::IDevice;
 using ::android::hardware::audio::CPP_VERSION::Result;
 using ::android::hardware::Return;
+using ::android::hardware::Void;
+using ::android::hidl::manager::V1_0::IServiceManager;
+using ::android::hidl::manager::V1_0::IServiceNotification;
 
 namespace android {
 namespace CPP_VERSION {
 
-DevicesFactoryHalHidl::DevicesFactoryHalHidl(sp<IDevicesFactory> devicesFactory) {
-    ALOG_ASSERT(devicesFactory != nullptr, "Provided IDevicesFactory service is NULL");
+class ServiceNotificationListener : public IServiceNotification {
+  public:
+    explicit ServiceNotificationListener(sp<DevicesFactoryHalHidl> factory)
+            : mFactory(factory) {}
 
-    mDeviceFactories.push_back(devicesFactory);
-    if (MAJOR_VERSION >= 4) {
-        // The MSD factory is optional and only available starting at HAL 4.0
-        sp<IDevicesFactory> msdFactory{IDevicesFactory::getService(AUDIO_HAL_SERVICE_NAME_MSD)};
-        if (msdFactory) {
-            mDeviceFactories.push_back(msdFactory);
+    Return<void> onRegistration(const hidl_string& /*fully_qualified_name*/,
+            const hidl_string& instance_name,
+            bool /*pre_existing*/) override {
+        if (static_cast<std::string>(instance_name) == "default") return Void();
+        sp<DevicesFactoryHalHidl> factory = mFactory.promote();
+        if (!factory) return Void();
+        sp<IDevicesFactory> halFactory = IDevicesFactory::getService(instance_name);
+        if (halFactory) {
+            factory->addDeviceFactory(halFactory, true /*needToNotify*/);
         }
+        return Void();
     }
-    for (const auto& factory : mDeviceFactories) {
-        // It is assumed that the DevicesFactoryHalInterface instance is owned
-        // by AudioFlinger and thus have the same lifespan.
-        factory->linkToDeath(HalDeathHandler::getInstance(), 0 /*cookie*/);
-    }
+
+  private:
+    wp<DevicesFactoryHalHidl> mFactory;
+};
+
+DevicesFactoryHalHidl::DevicesFactoryHalHidl(sp<IDevicesFactory> devicesFactory) {
+    ALOG_ASSERT(devicesFactory != nullptr, "Provided default IDevicesFactory service is NULL");
+    addDeviceFactory(devicesFactory, false /*needToNotify*/);
 }
 
+void DevicesFactoryHalHidl::onFirstRef() {
+    sp<IServiceManager> sm = IServiceManager::getService();
+    ALOG_ASSERT(sm != nullptr, "Hardware service manager is not running");
+    sp<ServiceNotificationListener> listener = new ServiceNotificationListener(this);
+    Return<bool> result = sm->registerForNotifications(
+            IDevicesFactory::descriptor, "", listener);
+    if (result.isOk()) {
+        ALOGE_IF(!static_cast<bool>(result),
+                "Hardware service manager refused to register listener");
+    } else {
+        ALOGE("Failed to register for hardware service manager notifications: %s",
+                result.description().c_str());
+    }
+}
 
 #if MAJOR_VERSION == 2
 static IDevicesFactory::Device idFromHal(const char *name, status_t* status) {
@@ -83,12 +108,13 @@
 #endif
 
 status_t DevicesFactoryHalHidl::openDevice(const char *name, sp<DeviceHalInterface> *device) {
-    if (mDeviceFactories.empty()) return NO_INIT;
+    auto factories = copyDeviceFactories();
+    if (factories.empty()) return NO_INIT;
     status_t status;
     auto hidlId = idFromHal(name, &status);
     if (status != OK) return status;
     Result retval = Result::NOT_INITIALIZED;
-    for (const auto& factory : mDeviceFactories) {
+    for (const auto& factory : factories) {
         Return<void> ret = factory->openDevice(
                 hidlId,
                 [&](Result r, const sp<IDevice>& result) {
@@ -113,10 +139,9 @@
 
 status_t DevicesFactoryHalHidl::getHalPids(std::vector<pid_t> *pids) {
     std::set<pid_t> pidsSet;
-
-    for (const auto& factory : mDeviceFactories) {
+    auto factories = copyDeviceFactories();
+    for (const auto& factory : factories) {
         using ::android::hidl::base::V1_0::DebugInfo;
-        using android::hidl::manager::V1_0::IServiceManager;
 
         DebugInfo debugInfo;
         auto ret = factory->getDebugInfo([&] (const auto &info) {
@@ -135,5 +160,48 @@
     return NO_ERROR;
 }
 
+status_t DevicesFactoryHalHidl::setCallbackOnce(sp<DevicesFactoryHalCallback> callback) {
+    ALOG_ASSERT(callback != nullptr);
+    bool needToCallCallback = false;
+    {
+        std::lock_guard<std::mutex> lock(mLock);
+        if (mCallback.unsafe_get()) return INVALID_OPERATION;
+        mCallback = callback;
+        if (mHaveUndeliveredNotifications) {
+            needToCallCallback = true;
+            mHaveUndeliveredNotifications = false;
+        }
+    }
+    if (needToCallCallback) {
+        callback->onNewDevicesAvailable();
+    }
+    return NO_ERROR;
+}
+
+void DevicesFactoryHalHidl::addDeviceFactory(sp<IDevicesFactory> factory, bool needToNotify) {
+    // It is assumed that the DevicesFactoryHalInterface instance is owned
+    // by AudioFlinger and thus have the same lifespan.
+    factory->linkToDeath(HalDeathHandler::getInstance(), 0 /*cookie*/);
+    sp<DevicesFactoryHalCallback> callback;
+    {
+        std::lock_guard<std::mutex> lock(mLock);
+        mDeviceFactories.push_back(factory);
+        if (needToNotify) {
+            callback = mCallback.promote();
+            if (!callback) {
+                mHaveUndeliveredNotifications = true;
+            }
+        }
+    }
+    if (callback) {
+        callback->onNewDevicesAvailable();
+    }
+}
+
+std::vector<sp<IDevicesFactory>> DevicesFactoryHalHidl::copyDeviceFactories() {
+    std::lock_guard<std::mutex> lock(mLock);
+    return mDeviceFactories;
+}
+
 } // namespace CPP_VERSION
 } // namespace android
diff --git a/media/libaudiohal/impl/DevicesFactoryHalHidl.h b/media/libaudiohal/impl/DevicesFactoryHalHidl.h
index 52185c8..6f84efe 100644
--- a/media/libaudiohal/impl/DevicesFactoryHalHidl.h
+++ b/media/libaudiohal/impl/DevicesFactoryHalHidl.h
@@ -17,6 +17,9 @@
 #ifndef ANDROID_HARDWARE_DEVICES_FACTORY_HAL_HIDL_H
 #define ANDROID_HARDWARE_DEVICES_FACTORY_HAL_HIDL_H
 
+#include <mutex>
+#include <vector>
+
 #include PATH(android/hardware/audio/FILE_VERSION/IDevicesFactory.h)
 #include <media/audiohal/DevicesFactoryHalInterface.h>
 #include <utils/Errors.h>
@@ -32,16 +35,26 @@
 class DevicesFactoryHalHidl : public DevicesFactoryHalInterface
 {
   public:
-    DevicesFactoryHalHidl(sp<IDevicesFactory> devicesFactory);
+    explicit DevicesFactoryHalHidl(sp<IDevicesFactory> devicesFactory);
+    void onFirstRef() override;
 
     // Opens a device with the specified name. To close the device, it is
     // necessary to release references to the returned object.
-    virtual status_t openDevice(const char *name, sp<DeviceHalInterface> *device);
+    status_t openDevice(const char *name, sp<DeviceHalInterface> *device) override;
 
-            status_t getHalPids(std::vector<pid_t> *pids) override;
+    status_t getHalPids(std::vector<pid_t> *pids) override;
+
+    status_t setCallbackOnce(sp<DevicesFactoryHalCallback> callback) override;
 
   private:
-    std::vector<sp<IDevicesFactory>> mDeviceFactories;
+    friend class ServiceNotificationListener;
+    void addDeviceFactory(sp<IDevicesFactory> factory, bool needToNotify);
+    std::vector<sp<IDevicesFactory>> copyDeviceFactories();
+
+    std::mutex mLock;
+    std::vector<sp<IDevicesFactory>> mDeviceFactories;  // GUARDED_BY(mLock)
+    wp<DevicesFactoryHalCallback> mCallback;  // GUARDED_BY(mLock)
+    bool mHaveUndeliveredNotifications = false;  // GUARDED_BY(mLock)
 
     virtual ~DevicesFactoryHalHidl() = default;
 };
diff --git a/media/libaudiohal/impl/DevicesFactoryHalHybrid.cpp b/media/libaudiohal/impl/DevicesFactoryHalHybrid.cpp
index 52f150a..cde8d85 100644
--- a/media/libaudiohal/impl/DevicesFactoryHalHybrid.cpp
+++ b/media/libaudiohal/impl/DevicesFactoryHalHybrid.cpp
@@ -44,6 +44,13 @@
     return INVALID_OPERATION;
 }
 
+status_t DevicesFactoryHalHybrid::setCallbackOnce(sp<DevicesFactoryHalCallback> callback) {
+    if (mHidlFactory) {
+        return mHidlFactory->setCallbackOnce(callback);
+    }
+    return INVALID_OPERATION;
+}
+
 } // namespace CPP_VERSION
 
 extern "C" __attribute__((visibility("default"))) void* createIDevicesFactory() {
diff --git a/media/libaudiohal/impl/DevicesFactoryHalHybrid.h b/media/libaudiohal/impl/DevicesFactoryHalHybrid.h
index 2189b36..568a1fb 100644
--- a/media/libaudiohal/impl/DevicesFactoryHalHybrid.h
+++ b/media/libaudiohal/impl/DevicesFactoryHalHybrid.h
@@ -38,6 +38,8 @@
 
             status_t getHalPids(std::vector<pid_t> *pids) override;
 
+            status_t setCallbackOnce(sp<DevicesFactoryHalCallback> callback) override;
+
   private:
     sp<DevicesFactoryHalInterface> mLocalFactory;
     sp<DevicesFactoryHalInterface> mHidlFactory;
diff --git a/media/libaudiohal/impl/DevicesFactoryHalLocal.h b/media/libaudiohal/impl/DevicesFactoryHalLocal.h
index 2b011f4..32bf362 100644
--- a/media/libaudiohal/impl/DevicesFactoryHalLocal.h
+++ b/media/libaudiohal/impl/DevicesFactoryHalLocal.h
@@ -37,6 +37,10 @@
                 return INVALID_OPERATION;
             }
 
+            status_t setCallbackOnce(sp<DevicesFactoryHalCallback> callback __unused) override {
+                return INVALID_OPERATION;
+            }
+
   private:
     friend class DevicesFactoryHalHybrid;