diff --git a/media/libmedia/AudioSystem.cpp b/media/libmedia/AudioSystem.cpp
index f13bcf3..3bfb09a 100644
--- a/media/libmedia/AudioSystem.cpp
+++ b/media/libmedia/AudioSystem.cpp
@@ -476,11 +476,13 @@
         switch (event) {
         case AUDIO_OUTPUT_OPENED:
         case AUDIO_INPUT_OPENED: {
-            if (getIoDescriptor(ioDesc->mIoHandle) != 0) {
-                ALOGV("ioConfigChanged() opening already existing output! %d", ioDesc->mIoHandle);
-                break;
+            sp<AudioIoDescriptor> oldDesc = getIoDescriptor(ioDesc->mIoHandle);
+            if (oldDesc == 0) {
+                mIoDescriptors.add(ioDesc->mIoHandle, ioDesc);
+            } else {
+                deviceId = oldDesc->getDeviceId();
+                mIoDescriptors.replaceValueFor(ioDesc->mIoHandle, ioDesc);
             }
-            mIoDescriptors.add(ioDesc->mIoHandle, ioDesc);
 
             if (ioDesc->getDeviceId() != AUDIO_PORT_HANDLE_NONE) {
                 deviceId = ioDesc->getDeviceId();
@@ -1074,7 +1076,14 @@
     if (afc == 0) {
         return NO_INIT;
     }
-    return afc->addAudioDeviceCallback(callback, audioIo);
+    status_t status = afc->addAudioDeviceCallback(callback, audioIo);
+    if (status == NO_ERROR) {
+        const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
+        if (af != 0) {
+            af->registerClient(afc);
+        }
+    }
+    return status;
 }
 
 status_t AudioSystem::removeAudioDeviceCallback(
diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index ae869d6..0ecfb1e 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -1335,21 +1335,23 @@
       mCallbackCookie(NULL),
       mCallbackData(NULL),
       mBytesWritten(0),
+      mStreamType(AUDIO_STREAM_MUSIC),
+      mAttributes(attr),
+      mLeftVolume(1.0),
+      mRightVolume(1.0),
+      mPlaybackRate(AUDIO_PLAYBACK_RATE_DEFAULT),
+      mSampleRateHz(0),
+      mMsecsPerFrame(0),
+      mFrameSize(0),
       mSessionId(sessionId),
       mUid(uid),
       mPid(pid),
-      mFlags(AUDIO_OUTPUT_FLAG_NONE) {
+      mSendLevel(0.0),
+      mAuxEffectId(0),
+      mFlags(AUDIO_OUTPUT_FLAG_NONE)
+{
     ALOGV("AudioOutput(%d)", sessionId);
-    mStreamType = AUDIO_STREAM_MUSIC;
-    mLeftVolume = 1.0;
-    mRightVolume = 1.0;
-    mPlaybackRate = AUDIO_PLAYBACK_RATE_DEFAULT;
-    mSampleRateHz = 0;
-    mMsecsPerFrame = 0;
-    mAuxEffectId = 0;
-    mSendLevel = 0.0;
     setMinBufferCount();
-    mAttributes = attr;
 }
 
 MediaPlayerService::AudioOutput::~AudioOutput()
@@ -1358,6 +1360,7 @@
     delete mCallbackData;
 }
 
+//static
 void MediaPlayerService::AudioOutput::setMinBufferCount()
 {
     char value[PROPERTY_VALUE_MAX];
@@ -1367,92 +1370,105 @@
     }
 }
 
+// static
 bool MediaPlayerService::AudioOutput::isOnEmulator()
 {
-    setMinBufferCount();
+    setMinBufferCount(); // benign race wrt other threads
     return mIsOnEmulator;
 }
 
+// static
 int MediaPlayerService::AudioOutput::getMinBufferCount()
 {
-    setMinBufferCount();
+    setMinBufferCount(); // benign race wrt other threads
     return mMinBufferCount;
 }
 
 ssize_t MediaPlayerService::AudioOutput::bufferSize() const
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return NO_INIT;
-    return mTrack->frameCount() * frameSize();
+    return mTrack->frameCount() * mFrameSize;
 }
 
 ssize_t MediaPlayerService::AudioOutput::frameCount() const
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return NO_INIT;
     return mTrack->frameCount();
 }
 
 ssize_t MediaPlayerService::AudioOutput::channelCount() const
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return NO_INIT;
     return mTrack->channelCount();
 }
 
 ssize_t MediaPlayerService::AudioOutput::frameSize() const
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return NO_INIT;
-    return mTrack->frameSize();
+    return mFrameSize;
 }
 
 uint32_t MediaPlayerService::AudioOutput::latency () const
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return 0;
     return mTrack->latency();
 }
 
 float MediaPlayerService::AudioOutput::msecsPerFrame() const
 {
+    Mutex::Autolock lock(mLock);
     return mMsecsPerFrame;
 }
 
 status_t MediaPlayerService::AudioOutput::getPosition(uint32_t *position) const
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return NO_INIT;
     return mTrack->getPosition(position);
 }
 
 status_t MediaPlayerService::AudioOutput::getTimestamp(AudioTimestamp &ts) const
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return NO_INIT;
     return mTrack->getTimestamp(ts);
 }
 
 status_t MediaPlayerService::AudioOutput::getFramesWritten(uint32_t *frameswritten) const
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return NO_INIT;
-    *frameswritten = mBytesWritten / frameSize();
+    *frameswritten = mBytesWritten / mFrameSize;
     return OK;
 }
 
 status_t MediaPlayerService::AudioOutput::setParameters(const String8& keyValuePairs)
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return NO_INIT;
     return mTrack->setParameters(keyValuePairs);
 }
 
 String8  MediaPlayerService::AudioOutput::getParameters(const String8& keys)
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return String8::empty();
     return mTrack->getParameters(keys);
 }
 
 void MediaPlayerService::AudioOutput::setAudioAttributes(const audio_attributes_t * attributes) {
+    Mutex::Autolock lock(mLock);
     mAttributes = attributes;
 }
 
-void MediaPlayerService::AudioOutput::deleteRecycledTrack()
+void MediaPlayerService::AudioOutput::deleteRecycledTrack_l()
 {
-    ALOGV("deleteRecycledTrack");
-
+    ALOGV("deleteRecycledTrack_l");
     if (mRecycledTrack != 0) {
 
         if (mCallbackData != NULL) {
@@ -1470,12 +1486,17 @@
         // AudioFlinger to drain the track.
 
         mRecycledTrack.clear();
+        close_l();
         delete mCallbackData;
         mCallbackData = NULL;
-        close();
     }
 }
 
+void MediaPlayerService::AudioOutput::close_l()
+{
+    mTrack.clear();
+}
+
 status_t MediaPlayerService::AudioOutput::open(
         uint32_t sampleRate, int channelCount, audio_channel_mask_t channelMask,
         audio_format_t format, int bufferCount,
@@ -1535,6 +1556,7 @@
         }
     }
 
+    Mutex::Autolock lock(mLock);
     mCallback = cb;
     mCallbackCookie = cookie;
 
@@ -1577,7 +1599,7 @@
     // we must close the previous output before opening a new one
     if (bothOffloaded && !reuse) {
         ALOGV("both offloaded and not recycling");
-        deleteRecycledTrack();
+        deleteRecycledTrack_l();
     }
 
     sp<AudioTrack> t;
@@ -1655,7 +1677,7 @@
 
         if (reuse) {
             ALOGV("chaining to next output and recycling track");
-            close();
+            close_l();
             mTrack = mRecycledTrack;
             mRecycledTrack.clear();
             if (mCallbackData != NULL) {
@@ -1669,7 +1691,7 @@
     // we're not going to reuse the track, unblock and flush it
     // this was done earlier if both tracks are offloaded
     if (!bothOffloaded) {
-        deleteRecycledTrack();
+        deleteRecycledTrack_l();
     }
 
     CHECK((t != NULL) && ((mCallback == NULL) || (newcbd != NULL)));
@@ -1681,9 +1703,10 @@
     mSampleRateHz = sampleRate;
     mFlags = t->getFlags(); // we suggest the flags above, but new AudioTrack() may not grant it.
     mMsecsPerFrame = 1E3f / (mPlaybackRate.mSpeed * sampleRate);
+    mFrameSize = t->frameSize();
     uint32_t pos;
     if (t->getPosition(&pos) == OK) {
-        mBytesWritten = uint64_t(pos) * t->frameSize();
+        mBytesWritten = uint64_t(pos) * mFrameSize;
     }
     mTrack = t;
 
@@ -1704,6 +1727,7 @@
 status_t MediaPlayerService::AudioOutput::start()
 {
     ALOGV("start");
+    Mutex::Autolock lock(mLock);
     if (mCallbackData != NULL) {
         mCallbackData->endTrackSwitch();
     }
@@ -1716,30 +1740,88 @@
 }
 
 void MediaPlayerService::AudioOutput::setNextOutput(const sp<AudioOutput>& nextOutput) {
+    Mutex::Autolock lock(mLock);
     mNextOutput = nextOutput;
 }
 
-
 void MediaPlayerService::AudioOutput::switchToNextOutput() {
     ALOGV("switchToNextOutput");
-    if (mNextOutput != NULL) {
-        if (mCallbackData != NULL) {
-            mCallbackData->beginTrackSwitch();
+
+    // Try to acquire the callback lock before moving track (without incurring deadlock).
+    const unsigned kMaxSwitchTries = 100;
+    Mutex::Autolock lock(mLock);
+    for (unsigned tries = 0;;) {
+        if (mTrack == 0) {
+            return;
         }
-        delete mNextOutput->mCallbackData;
-        mNextOutput->mCallbackData = mCallbackData;
-        mCallbackData = NULL;
-        mNextOutput->mRecycledTrack = mTrack;
-        mTrack.clear();
-        mNextOutput->mSampleRateHz = mSampleRateHz;
-        mNextOutput->mMsecsPerFrame = mMsecsPerFrame;
-        mNextOutput->mBytesWritten = mBytesWritten;
-        mNextOutput->mFlags = mFlags;
+        if (mNextOutput != NULL && mNextOutput != this) {
+            if (mCallbackData != NULL) {
+                // two alternative approaches
+#if 1
+                CallbackData *callbackData = mCallbackData;
+                mLock.unlock();
+                // proper acquisition sequence
+                callbackData->lock();
+                mLock.lock();
+                // Caution: it is unlikely that someone deleted our callback or changed our target
+                if (callbackData != mCallbackData || mNextOutput == NULL || mNextOutput == this) {
+                    // fatal if we are starved out.
+                    LOG_ALWAYS_FATAL_IF(++tries > kMaxSwitchTries,
+                            "switchToNextOutput() cannot obtain correct lock sequence");
+                    callbackData->unlock();
+                    continue;
+                }
+                callbackData->mSwitching = true; // begin track switch
+#else
+                // tryBeginTrackSwitch() returns false if the callback has the lock.
+                if (!mCallbackData->tryBeginTrackSwitch()) {
+                    // fatal if we are starved out.
+                    LOG_ALWAYS_FATAL_IF(++tries > kMaxSwitchTries,
+                            "switchToNextOutput() cannot obtain callback lock");
+                    mLock.unlock();
+                    usleep(5 * 1000 /* usec */); // allow callback to use AudioOutput
+                    mLock.lock();
+                    continue;
+                }
+#endif
+            }
+
+            Mutex::Autolock nextLock(mNextOutput->mLock);
+
+            // If the next output track is not NULL, then it has been
+            // opened already for playback.
+            // This is possible even without the next player being started,
+            // for example, the next player could be prepared and seeked.
+            //
+            // Presuming it isn't advisable to force the track over.
+             if (mNextOutput->mTrack == NULL) {
+                ALOGD("Recycling track for gapless playback");
+                delete mNextOutput->mCallbackData;
+                mNextOutput->mCallbackData = mCallbackData;
+                mNextOutput->mRecycledTrack = mTrack;
+                mNextOutput->mSampleRateHz = mSampleRateHz;
+                mNextOutput->mMsecsPerFrame = mMsecsPerFrame;
+                mNextOutput->mBytesWritten = mBytesWritten;
+                mNextOutput->mFlags = mFlags;
+                mNextOutput->mFrameSize = mFrameSize;
+                close_l();
+                mCallbackData = NULL;  // destruction handled by mNextOutput
+            } else {
+                ALOGW("Ignoring gapless playback because next player has already started");
+                // remove track in case resource needed for future players.
+                if (mCallbackData != NULL) {
+                    mCallbackData->endTrackSwitch();  // release lock for callbacks before close.
+                }
+                close_l();
+            }
+        }
+        break;
     }
 }
 
 ssize_t MediaPlayerService::AudioOutput::write(const void* buffer, size_t size, bool blocking)
 {
+    Mutex::Autolock lock(mLock);
     LOG_ALWAYS_FATAL_IF(mCallback != NULL, "Don't call write if supplying a callback.");
 
     //ALOGV("write(%p, %u)", buffer, size);
@@ -1756,6 +1838,7 @@
 void MediaPlayerService::AudioOutput::stop()
 {
     ALOGV("stop");
+    Mutex::Autolock lock(mLock);
     mBytesWritten = 0;
     if (mTrack != 0) mTrack->stop();
 }
@@ -1763,6 +1846,7 @@
 void MediaPlayerService::AudioOutput::flush()
 {
     ALOGV("flush");
+    Mutex::Autolock lock(mLock);
     mBytesWritten = 0;
     if (mTrack != 0) mTrack->flush();
 }
@@ -1770,18 +1854,21 @@
 void MediaPlayerService::AudioOutput::pause()
 {
     ALOGV("pause");
+    Mutex::Autolock lock(mLock);
     if (mTrack != 0) mTrack->pause();
 }
 
 void MediaPlayerService::AudioOutput::close()
 {
     ALOGV("close");
-    mTrack.clear();
+    Mutex::Autolock lock(mLock);
+    close_l();
 }
 
 void MediaPlayerService::AudioOutput::setVolume(float left, float right)
 {
     ALOGV("setVolume(%f, %f)", left, right);
+    Mutex::Autolock lock(mLock);
     mLeftVolume = left;
     mRightVolume = right;
     if (mTrack != 0) {
@@ -1793,6 +1880,7 @@
 {
     ALOGV("setPlaybackRate(%f %f %d %d)",
                 rate.mSpeed, rate.mPitch, rate.mFallbackMode, rate.mStretchMode);
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) {
         // remember rate so that we can set it when the track is opened
         mPlaybackRate = rate;
@@ -1814,6 +1902,7 @@
 status_t MediaPlayerService::AudioOutput::getPlaybackRate(AudioPlaybackRate *rate)
 {
     ALOGV("setPlaybackRate");
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) {
         return NO_INIT;
     }
@@ -1824,6 +1913,7 @@
 status_t MediaPlayerService::AudioOutput::setAuxEffectSendLevel(float level)
 {
     ALOGV("setAuxEffectSendLevel(%f)", level);
+    Mutex::Autolock lock(mLock);
     mSendLevel = level;
     if (mTrack != 0) {
         return mTrack->setAuxEffectSendLevel(level);
@@ -1834,6 +1924,7 @@
 status_t MediaPlayerService::AudioOutput::attachAuxEffect(int effectId)
 {
     ALOGV("attachAuxEffect(%d)", effectId);
+    Mutex::Autolock lock(mLock);
     mAuxEffectId = effectId;
     if (mTrack != 0) {
         return mTrack->attachAuxEffect(effectId);
@@ -1846,6 +1937,7 @@
         int event, void *cookie, void *info) {
     //ALOGV("callbackwrapper");
     CallbackData *data = (CallbackData*)cookie;
+    // lock to ensure we aren't caught in the middle of a track switch.
     data->lock();
     AudioOutput *me = data->getOutput();
     AudioTrack::Buffer *buffer = (AudioTrack::Buffer *)info;
@@ -1915,11 +2007,13 @@
 
 int MediaPlayerService::AudioOutput::getSessionId() const
 {
+    Mutex::Autolock lock(mLock);
     return mSessionId;
 }
 
 uint32_t MediaPlayerService::AudioOutput::getSampleRate() const
 {
+    Mutex::Autolock lock(mLock);
     if (mTrack == 0) return 0;
     return mTrack->getSampleRate();
 }
diff --git a/media/libmediaplayerservice/MediaPlayerService.h b/media/libmediaplayerservice/MediaPlayerService.h
index 7527506..9e6ca52 100644
--- a/media/libmediaplayerservice/MediaPlayerService.h
+++ b/media/libmediaplayerservice/MediaPlayerService.h
@@ -132,7 +132,8 @@
         static void             setMinBufferCount();
         static void             CallbackWrapper(
                 int event, void *me, void *info);
-               void             deleteRecycledTrack();
+               void             deleteRecycledTrack_l();
+               void             close_l();
 
         sp<AudioTrack>          mTrack;
         sp<AudioTrack>          mRecycledTrack;
@@ -148,32 +149,47 @@
         AudioPlaybackRate       mPlaybackRate;
         uint32_t                mSampleRateHz; // sample rate of the content, as set in open()
         float                   mMsecsPerFrame;
+        size_t                  mFrameSize;
         int                     mSessionId;
         int                     mUid;
         int                     mPid;
         float                   mSendLevel;
         int                     mAuxEffectId;
+        audio_output_flags_t    mFlags;
+        mutable Mutex           mLock;
+
+        // static variables below not protected by mutex
         static bool             mIsOnEmulator;
         static int              mMinBufferCount;  // 12 for emulator; otherwise 4
-        audio_output_flags_t    mFlags;
 
         // CallbackData is what is passed to the AudioTrack as the "user" data.
         // We need to be able to target this to a different Output on the fly,
         // so we can't use the Output itself for this.
         class CallbackData {
+            friend AudioOutput;
         public:
             CallbackData(AudioOutput *cookie) {
                 mData = cookie;
                 mSwitching = false;
             }
-            AudioOutput *   getOutput() { return mData;}
+            AudioOutput *   getOutput() const { return mData; }
             void            setOutput(AudioOutput* newcookie) { mData = newcookie; }
             // lock/unlock are used by the callback before accessing the payload of this object
-            void            lock() { mLock.lock(); }
-            void            unlock() { mLock.unlock(); }
-            // beginTrackSwitch/endTrackSwitch are used when this object is being handed over
+            void            lock() const { mLock.lock(); }
+            void            unlock() const { mLock.unlock(); }
+
+            // tryBeginTrackSwitch/endTrackSwitch are used when the CallbackData is handed over
             // to the next sink.
-            void            beginTrackSwitch() { mLock.lock(); mSwitching = true; }
+
+            // tryBeginTrackSwitch() returns true only if it obtains the lock.
+            bool            tryBeginTrackSwitch() {
+                LOG_ALWAYS_FATAL_IF(mSwitching, "tryBeginTrackSwitch() already called");
+                if (mLock.tryLock() != OK) {
+                    return false;
+                }
+                mSwitching = true;
+                return true;
+            }
             void            endTrackSwitch() {
                 if (mSwitching) {
                     mLock.unlock();
@@ -182,7 +198,7 @@
             }
         private:
             AudioOutput *   mData;
-            mutable Mutex   mLock;
+            mutable Mutex   mLock; // a recursive mutex might make this unnecessary.
             bool            mSwitching;
             DISALLOW_EVIL_CONSTRUCTORS(CallbackData);
         };
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 52fce34..8f1e050 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -1252,11 +1252,9 @@
     if (client == 0) {
         return;
     }
-    bool clientAdded = false;
+    pid_t pid = IPCThreadState::self()->getCallingPid();
     {
         Mutex::Autolock _cl(mClientLock);
-
-        pid_t pid = IPCThreadState::self()->getCallingPid();
         if (mNotificationClients.indexOfKey(pid) < 0) {
             sp<NotificationClient> notificationClient = new NotificationClient(this,
                                                                                 client,
@@ -1267,22 +1265,19 @@
 
             sp<IBinder> binder = IInterface::asBinder(client);
             binder->linkToDeath(notificationClient);
-            clientAdded = true;
         }
     }
 
     // mClientLock should not be held here because ThreadBase::sendIoConfigEvent() will lock the
     // ThreadBase mutex and the locking order is ThreadBase::mLock then AudioFlinger::mClientLock.
-    if (clientAdded) {
-        // the config change is always sent from playback or record threads to avoid deadlock
-        // with AudioSystem::gLock
-        for (size_t i = 0; i < mPlaybackThreads.size(); i++) {
-            mPlaybackThreads.valueAt(i)->sendIoConfigEvent(AUDIO_OUTPUT_OPENED);
-        }
+    // the config change is always sent from playback or record threads to avoid deadlock
+    // with AudioSystem::gLock
+    for (size_t i = 0; i < mPlaybackThreads.size(); i++) {
+        mPlaybackThreads.valueAt(i)->sendIoConfigEvent(AUDIO_OUTPUT_OPENED, pid);
+    }
 
-        for (size_t i = 0; i < mRecordThreads.size(); i++) {
-            mRecordThreads.valueAt(i)->sendIoConfigEvent(AUDIO_INPUT_OPENED);
-        }
+    for (size_t i = 0; i < mRecordThreads.size(); i++) {
+        mRecordThreads.valueAt(i)->sendIoConfigEvent(AUDIO_INPUT_OPENED, pid);
     }
 }
 
@@ -1316,12 +1311,15 @@
 }
 
 void AudioFlinger::ioConfigChanged(audio_io_config_event event,
-                                   const sp<AudioIoDescriptor>& ioDesc)
+                                   const sp<AudioIoDescriptor>& ioDesc,
+                                   pid_t pid)
 {
     Mutex::Autolock _l(mClientLock);
     size_t size = mNotificationClients.size();
     for (size_t i = 0; i < size; i++) {
-        mNotificationClients.valueAt(i)->audioFlingerClient()->ioConfigChanged(event, ioDesc);
+        if ((pid == 0) || (mNotificationClients.keyAt(i) == pid)) {
+            mNotificationClients.valueAt(i)->audioFlingerClient()->ioConfigChanged(event, ioDesc);
+        }
     }
 }
 
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index d087ced..4f7e27d 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -559,7 +559,8 @@
               float streamVolume_l(audio_stream_type_t stream) const
                                 { return mStreamTypes[stream].volume; }
               void ioConfigChanged(audio_io_config_event event,
-                                   const sp<AudioIoDescriptor>& ioDesc);
+                                   const sp<AudioIoDescriptor>& ioDesc,
+                                   pid_t pid = 0);
 
               // Allocate an audio_io_handle_t, session ID, effect ID, or audio_module_handle_t.
               // They all share the same ID space, but the namespaces are actually independent
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index d3ea9d8..0880c5d 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -532,7 +532,8 @@
         // RecordThread::readInputParameters_l()
         //FIXME: mStandby should be true here. Is this some kind of hack?
         mStandby(false), mOutDevice(outDevice), mInDevice(inDevice),
-        mPrevInDevice(AUDIO_DEVICE_NONE), mAudioSource(AUDIO_SOURCE_DEFAULT), mId(id),
+        mPrevOutDevice(AUDIO_DEVICE_NONE), mPrevInDevice(AUDIO_DEVICE_NONE),
+        mAudioSource(AUDIO_SOURCE_DEFAULT), mId(id),
         // mName will be set by concrete (non-virtual) subclass
         mDeathRecipient(new PMDeathRecipient(this)),
         mSystemReady(systemReady)
@@ -627,16 +628,16 @@
     return status;
 }
 
-void AudioFlinger::ThreadBase::sendIoConfigEvent(audio_io_config_event event)
+void AudioFlinger::ThreadBase::sendIoConfigEvent(audio_io_config_event event, pid_t pid)
 {
     Mutex::Autolock _l(mLock);
-    sendIoConfigEvent_l(event);
+    sendIoConfigEvent_l(event, pid);
 }
 
 // sendIoConfigEvent_l() must be called with ThreadBase::mLock held
-void AudioFlinger::ThreadBase::sendIoConfigEvent_l(audio_io_config_event event)
+void AudioFlinger::ThreadBase::sendIoConfigEvent_l(audio_io_config_event event, pid_t pid)
 {
-    sp<ConfigEvent> configEvent = (ConfigEvent *)new IoConfigEvent(event);
+    sp<ConfigEvent> configEvent = (ConfigEvent *)new IoConfigEvent(event, pid);
     sendConfigEvent_l(configEvent);
 }
 
@@ -706,7 +707,7 @@
         } break;
         case CFG_EVENT_IO: {
             IoConfigEventData *data = (IoConfigEventData *)event->mData.get();
-            ioConfigChanged(data->mEvent);
+            ioConfigChanged(data->mEvent, data->mPid);
         } break;
         case CFG_EVENT_SET_PARAMETER: {
             SetParameterConfigEventData *data = (SetParameterConfigEventData *)event->mData.get();
@@ -1999,7 +2000,7 @@
     return out_s8;
 }
 
-void AudioFlinger::PlaybackThread::ioConfigChanged(audio_io_config_event event) {
+void AudioFlinger::PlaybackThread::ioConfigChanged(audio_io_config_event event, pid_t pid) {
     sp<AudioIoDescriptor> desc = new AudioIoDescriptor();
     ALOGV("PlaybackThread::ioConfigChanged, thread %p, event %d", this, event);
 
@@ -2021,7 +2022,7 @@
     default:
         break;
     }
-    mAudioFlinger->ioConfigChanged(event, desc);
+    mAudioFlinger->ioConfigChanged(event, desc, pid);
 }
 
 void AudioFlinger::PlaybackThread::writeCallback()
@@ -3133,7 +3134,10 @@
     for (size_t i = 0; i < mEffectChains.size(); i++) {
         mEffectChains[i]->setDevice_l(type);
     }
-    bool configChanged = mOutDevice != type;
+
+    // mPrevOutDevice is the latest device set by createAudioPatch_l(). It is not set when
+    // the thread is created so that the first patch creation triggers an ioConfigChanged callback
+    bool configChanged = mPrevOutDevice != type;
     mOutDevice = type;
     mPatch = *patch;
 
@@ -3163,6 +3167,7 @@
         *handle = AUDIO_PATCH_HANDLE_NONE;
     }
     if (configChanged) {
+        mPrevOutDevice = type;
         sendIoConfigEvent_l(AUDIO_OUTPUT_CONFIG_CHANGED);
     }
     return status;
@@ -6868,7 +6873,7 @@
     return out_s8;
 }
 
-void AudioFlinger::RecordThread::ioConfigChanged(audio_io_config_event event) {
+void AudioFlinger::RecordThread::ioConfigChanged(audio_io_config_event event, pid_t pid) {
     sp<AudioIoDescriptor> desc = new AudioIoDescriptor();
 
     desc->mIoHandle = mId;
@@ -6888,7 +6893,7 @@
     default:
         break;
     }
-    mAudioFlinger->ioConfigChanged(event, desc);
+    mAudioFlinger->ioConfigChanged(event, desc, pid);
 }
 
 void AudioFlinger::RecordThread::readInputParameters_l()
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 0783371..46ac300 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -104,21 +104,22 @@
 
     class IoConfigEventData : public ConfigEventData {
     public:
-        IoConfigEventData(audio_io_config_event event) :
-            mEvent(event) {}
+        IoConfigEventData(audio_io_config_event event, pid_t pid) :
+            mEvent(event), mPid(pid) {}
 
         virtual  void dump(char *buffer, size_t size) {
             snprintf(buffer, size, "IO event: event %d\n", mEvent);
         }
 
         const audio_io_config_event mEvent;
+        const pid_t                 mPid;
     };
 
     class IoConfigEvent : public ConfigEvent {
     public:
-        IoConfigEvent(audio_io_config_event event) :
+        IoConfigEvent(audio_io_config_event event, pid_t pid) :
             ConfigEvent(CFG_EVENT_IO) {
-            mData = new IoConfigEventData(event);
+            mData = new IoConfigEventData(event, pid);
         }
         virtual ~IoConfigEvent() {}
     };
@@ -255,13 +256,13 @@
                                                     status_t& status) = 0;
     virtual     status_t    setParameters(const String8& keyValuePairs);
     virtual     String8     getParameters(const String8& keys) = 0;
-    virtual     void        ioConfigChanged(audio_io_config_event event) = 0;
+    virtual     void        ioConfigChanged(audio_io_config_event event, pid_t pid = 0) = 0;
                 // sendConfigEvent_l() must be called with ThreadBase::mLock held
                 // Can temporarily release the lock if waiting for a reply from
                 // processConfigEvents_l().
                 status_t    sendConfigEvent_l(sp<ConfigEvent>& event);
-                void        sendIoConfigEvent(audio_io_config_event event);
-                void        sendIoConfigEvent_l(audio_io_config_event event);
+                void        sendIoConfigEvent(audio_io_config_event event, pid_t pid = 0);
+                void        sendIoConfigEvent_l(audio_io_config_event event, pid_t pid = 0);
                 void        sendPrioConfigEvent(pid_t pid, pid_t tid, int32_t prio);
                 void        sendPrioConfigEvent_l(pid_t pid, pid_t tid, int32_t prio);
                 status_t    sendSetParameterConfigEvent_l(const String8& keyValuePair);
@@ -436,6 +437,7 @@
                 bool                    mStandby;     // Whether thread is currently in standby.
                 audio_devices_t         mOutDevice;   // output device
                 audio_devices_t         mInDevice;    // input device
+                audio_devices_t         mPrevOutDevice;   // previous output device
                 audio_devices_t         mPrevInDevice;    // previous input device
                 struct audio_patch      mPatch;
                 audio_source_t          mAudioSource;
@@ -572,7 +574,7 @@
                                 { return android_atomic_acquire_load(&mSuspended) > 0; }
 
     virtual     String8     getParameters(const String8& keys);
-    virtual     void        ioConfigChanged(audio_io_config_event event);
+    virtual     void        ioConfigChanged(audio_io_config_event event, pid_t pid = 0);
                 status_t    getRenderPosition(uint32_t *halFrames, uint32_t *dspFrames);
                 // FIXME rename mixBuffer() to sinkBuffer() and remove int16_t* dependency.
                 // Consider also removing and passing an explicit mMainBuffer initialization
@@ -1254,7 +1256,7 @@
                                                status_t& status);
     virtual void        cacheParameters_l() {}
     virtual String8     getParameters(const String8& keys);
-    virtual void        ioConfigChanged(audio_io_config_event event);
+    virtual void        ioConfigChanged(audio_io_config_event event, pid_t pid = 0);
     virtual status_t    createAudioPatch_l(const struct audio_patch *patch,
                                            audio_patch_handle_t *handle);
     virtual status_t    releaseAudioPatch_l(const audio_patch_handle_t handle);
diff --git a/services/audiopolicy/common/include/policy.h b/services/audiopolicy/common/include/policy.h
index 4eef02f2..4b73e3c 100755
--- a/services/audiopolicy/common/include/policy.h
+++ b/services/audiopolicy/common/include/policy.h
@@ -37,8 +37,9 @@
  * A device mask for all audio input and output devices where matching inputs/outputs on device
  * type alone is not enough: the address must match too
  */
-#define APM_AUDIO_DEVICE_MATCH_ADDRESS_ALL (AUDIO_DEVICE_IN_REMOTE_SUBMIX | \
-                                            AUDIO_DEVICE_OUT_REMOTE_SUBMIX)
+#define APM_AUDIO_DEVICE_OUT_MATCH_ADDRESS_ALL (AUDIO_DEVICE_OUT_REMOTE_SUBMIX)
+
+#define APM_AUDIO_DEVICE_IN_MATCH_ADDRESS_ALL (AUDIO_DEVICE_IN_REMOTE_SUBMIX)
 
 /**
  * Check if the state given correspond to an in call state.
@@ -80,5 +81,8 @@
  */
 static inline bool device_distinguishes_on_address(audio_devices_t device)
 {
-    return ((device & APM_AUDIO_DEVICE_MATCH_ADDRESS_ALL & ~AUDIO_DEVICE_BIT_IN) != 0);
+    return (((device & AUDIO_DEVICE_BIT_IN) != 0) &&
+            ((~AUDIO_DEVICE_BIT_IN & device & APM_AUDIO_DEVICE_IN_MATCH_ADDRESS_ALL) != 0)) ||
+           (((device & AUDIO_DEVICE_BIT_IN) == 0) &&
+            ((device & APM_AUDIO_DEVICE_OUT_MATCH_ADDRESS_ALL) != 0));
 }
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
index de204e5..6d99640 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
@@ -1076,6 +1076,9 @@
         beaconMuteLatency = handleEventForBeacon(STARTING_OUTPUT);
     }
 
+    // check active before incrementing usage count
+    bool force = !outputDesc->isActive();
+
     // increment usage count for this stream on the requested output:
     // NOTE that the usage count is the same for duplicated output and hardware output which is
     // necessary for a correct control of hardware output routing by startOutput() and stopOutput()
@@ -1091,7 +1094,6 @@
                             (strategy == STRATEGY_SONIFICATION_RESPECTFUL) ||
                             (beaconMuteLatency > 0);
         uint32_t waitMs = beaconMuteLatency;
-        bool force = false;
         for (size_t i = 0; i < mOutputs.size(); i++) {
             sp<AudioOutputDescriptor> desc = mOutputs.valueAt(i);
             if (desc != outputDesc) {