Implement audio device callback

Add class AudioSystem::AudioDeviceCallback notifying
AudioSystem clients upon device selection change on a given
input or output thread.
Maintain a list of installed callback per I/O handle in AudioSystem
and call registered callbacks when an OPEN of CONFIG_CHANGED event
is received on IAudioFlingerClient::ioConfigChanged().
Add methods to AudioTrack and AudioRecord to add and remove device
change callbacks.
Add methods to AudioTrack and AudioRecord to query currently selected
device.
ioConfigChanged() events now convey the audio patch describing
the input or output thread routing.

Fix AudioRecord failure to start when invalidation is
handled by start().

Change-Id: I9e938adf025fa712337c63b1e02a8c18f2a20d39

4 files changed, 320 insertions, 63 deletions

diff --git a/media/libmedia/AudioRecord.cpp b/media/libmedia/AudioRecord.cpp
index 23015c0..73fd3cb 100644
--- a/media/libmedia/AudioRecord.cpp
+++ b/media/libmedia/AudioRecord.cpp
@@ -112,6 +112,10 @@ AudioRecord::~AudioRecord()
             mAudioRecordThread->requestExitAndWait();
             mAudioRecordThread.clear();
         }
+        // No lock here: worst case we remove a NULL callback which will be a nop
+        if (mDeviceCallback != 0 && mInput != AUDIO_IO_HANDLE_NONE) {
+            AudioSystem::removeAudioDeviceCallback(mDeviceCallback, mInput);
+        }
         IInterface::asBinder(mAudioRecord)->unlinkToDeath(mDeathNotifier, this);
         mAudioRecord.clear();
         mCblkMemory.clear();
@@ -286,6 +290,8 @@ status_t AudioRecord::start(AudioSystem::sync_event_t event, int triggerSession)
     mNewPosition = mProxy->getPosition() + mUpdatePeriod;
     int32_t flags = android_atomic_acquire_load(&mCblk->mFlags);
 
+    mActive = true;
+
     status_t status = NO_ERROR;
     if (!(flags & CBLK_INVALID)) {
         status = mAudioRecord->start(event, triggerSession);
@@ -298,9 +304,9 @@ status_t AudioRecord::start(AudioSystem::sync_event_t event, int triggerSession)
     }
 
     if (status != NO_ERROR) {
+        mActive = false;
         ALOGE("start() status %d", status);
     } else {
-        mActive = true;
         sp<AudioRecordThread> t = mAudioRecordThread;
         if (t != 0) {
             t->resume();
@@ -425,6 +431,11 @@ status_t AudioRecord::setInputDevice(audio_port_handle_t deviceId) {
     AutoMutex lock(mLock);
     if (mSelectedDeviceId != deviceId) {
         mSelectedDeviceId = deviceId;
+        // stop capture so that audio policy manager does not reject the new instance start request
+        // as only one capture can be active at a time.
+        if (mAudioRecord != 0 && mActive) {
+            mAudioRecord->stop();
+        }
         android_atomic_or(CBLK_INVALID, &mCblk->mFlags);
     }
     return NO_ERROR;
@@ -435,6 +446,14 @@ audio_port_handle_t AudioRecord::getInputDevice() {
     return mSelectedDeviceId;
 }
 
+audio_port_handle_t AudioRecord::getRoutedDeviceId() {
+    AutoMutex lock(mLock);
+    if (mInput == AUDIO_IO_HANDLE_NONE) {
+        return AUDIO_PORT_HANDLE_NONE;
+    }
+    return AudioSystem::getDeviceIdForIo(mInput);
+}
+
 // -------------------------------------------------------------------------
 
 // must be called with mLock held
@@ -478,6 +497,10 @@ status_t AudioRecord::openRecord_l(size_t epoch, const String16& opPackageName)
         }
     }
 
+    if (mDeviceCallback != 0 && mInput != AUDIO_IO_HANDLE_NONE) {
+        AudioSystem::removeAudioDeviceCallback(mDeviceCallback, mInput);
+    }
+
     audio_io_handle_t input;
     status_t status = AudioSystem::getInputForAttr(&mAttributes, &input,
                                         (audio_session_t)mSessionId,
@@ -609,6 +632,10 @@ status_t AudioRecord::openRecord_l(size_t epoch, const String16& opPackageName)
     mDeathNotifier = new DeathNotifier(this);
     IInterface::asBinder(mAudioRecord)->linkToDeath(mDeathNotifier, this);
 
+    if (mDeviceCallback != 0) {
+        AudioSystem::addAudioDeviceCallback(mDeviceCallback, mInput);
+    }
+
     return NO_ERROR;
     }
 
@@ -1054,6 +1081,48 @@ status_t AudioRecord::restoreRecord_l(const char *from)
     return result;
 }
 
+status_t AudioRecord::addAudioDeviceCallback(const sp<AudioSystem::AudioDeviceCallback>& callback)
+{
+    if (callback == 0) {
+        ALOGW("%s adding NULL callback!", __FUNCTION__);
+        return BAD_VALUE;
+    }
+    AutoMutex lock(mLock);
+    if (mDeviceCallback == callback) {
+        ALOGW("%s adding same callback!", __FUNCTION__);
+        return INVALID_OPERATION;
+    }
+    status_t status = NO_ERROR;
+    if (mInput != AUDIO_IO_HANDLE_NONE) {
+        if (mDeviceCallback != 0) {
+            ALOGW("%s callback already present!", __FUNCTION__);
+            AudioSystem::removeAudioDeviceCallback(mDeviceCallback, mInput);
+        }
+        status = AudioSystem::addAudioDeviceCallback(callback, mInput);
+    }
+    mDeviceCallback = callback;
+    return status;
+}
+
+status_t AudioRecord::removeAudioDeviceCallback(
+        const sp<AudioSystem::AudioDeviceCallback>& callback)
+{
+    if (callback == 0) {
+        ALOGW("%s removing NULL callback!", __FUNCTION__);
+        return BAD_VALUE;
+    }
+    AutoMutex lock(mLock);
+    if (mDeviceCallback != callback) {
+        ALOGW("%s removing different callback!", __FUNCTION__);
+        return INVALID_OPERATION;
+    }
+    if (mInput != AUDIO_IO_HANDLE_NONE) {
+        AudioSystem::removeAudioDeviceCallback(mDeviceCallback, mInput);
+    }
+    mDeviceCallback = 0;
+    return NO_ERROR;
+}
+
 // =========================================================================
 
 void AudioRecord::DeathNotifier::binderDied(const wp<IBinder>& who __unused)
diff --git a/media/libmedia/AudioSystem.cpp b/media/libmedia/AudioSystem.cpp
index 85ed2b1..4c2e77b 100644
--- a/media/libmedia/AudioSystem.cpp
+++ b/media/libmedia/AudioSystem.cpp
@@ -76,6 +76,25 @@ const sp<IAudioFlinger> AudioSystem::get_audio_flinger()
     return af;
 }
 
+const sp<AudioSystem::AudioFlingerClient> AudioSystem::getAudioFlingerClient()
+{
+    // calling get_audio_flinger() will initialize gAudioFlingerClient if needed
+    const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
+    if (af == 0) return 0;
+    Mutex::Autolock _l(gLock);
+    return gAudioFlingerClient;
+}
+
+sp<AudioIoDescriptor> AudioSystem::getIoDescriptor(audio_io_handle_t ioHandle)
+{
+    sp<AudioIoDescriptor> desc;
+    const sp<AudioFlingerClient> afc = getAudioFlingerClient();
+    if (afc != 0) {
+        desc = afc->getIoDescriptor(ioHandle);
+    }
+    return desc;
+}
+
 /* static */ status_t AudioSystem::checkAudioFlinger()
 {
     if (defaultServiceManager()->checkService(String16("media.audio_flinger")) != 0) {
@@ -249,9 +268,7 @@ status_t AudioSystem::getSamplingRate(audio_io_handle_t output,
 {
     const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
     if (af == 0) return PERMISSION_DENIED;
-
-    LOG_ALWAYS_FATAL_IF(gAudioFlingerClient == 0);
-    sp<AudioIoDescriptor> outputDesc = gAudioFlingerClient->getIoDescriptor(output);
+    sp<AudioIoDescriptor> outputDesc = getIoDescriptor(output);
     if (outputDesc == 0) {
         ALOGV("getOutputSamplingRate() no output descriptor for output %d in gOutputs", output);
         *samplingRate = af->sampleRate(output);
@@ -290,9 +307,7 @@ status_t AudioSystem::getFrameCount(audio_io_handle_t output,
 {
     const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
     if (af == 0) return PERMISSION_DENIED;
-
-    LOG_ALWAYS_FATAL_IF(gAudioFlingerClient == 0);
-    sp<AudioIoDescriptor> outputDesc = gAudioFlingerClient->getIoDescriptor(output);
+    sp<AudioIoDescriptor> outputDesc = getIoDescriptor(output);
     if (outputDesc == 0) {
         *frameCount = af->frameCount(output);
     } else {
@@ -329,9 +344,7 @@ status_t AudioSystem::getLatency(audio_io_handle_t output,
 {
     const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
     if (af == 0) return PERMISSION_DENIED;
-
-    LOG_ALWAYS_FATAL_IF(gAudioFlingerClient == 0);
-    sp<AudioIoDescriptor> outputDesc = gAudioFlingerClient->getIoDescriptor(output);
+    sp<AudioIoDescriptor> outputDesc = getIoDescriptor(output);
     if (outputDesc == 0) {
         *latency = af->latency(output);
     } else {
@@ -346,10 +359,11 @@ status_t AudioSystem::getLatency(audio_io_handle_t output,
 status_t AudioSystem::getInputBufferSize(uint32_t sampleRate, audio_format_t format,
         audio_channel_mask_t channelMask, size_t* buffSize)
 {
-    const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
-    if (af == 0) return PERMISSION_DENIED;
-    LOG_ALWAYS_FATAL_IF(gAudioFlingerClient == 0);
-    return gAudioFlingerClient->getInputBufferSize(sampleRate, format, channelMask, buffSize);
+    const sp<AudioFlingerClient> afc = getAudioFlingerClient();
+    if (afc == 0) {
+        return NO_INIT;
+    }
+    return afc->getInputBufferSize(sampleRate, format, channelMask, buffSize);
 }
 
 status_t AudioSystem::setVoiceVolume(float value)
@@ -446,47 +460,77 @@ void AudioSystem::AudioFlingerClient::ioConfigChanged(audio_io_config_event even
 
     if (ioDesc == 0 || ioDesc->mIoHandle == AUDIO_IO_HANDLE_NONE) return;
 
-    Mutex::Autolock _l(mLock);
+    audio_port_handle_t deviceId = AUDIO_PORT_HANDLE_NONE;
+    Vector < sp<AudioDeviceCallback> > callbacks;
 
-    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;
-        }
-        mIoDescriptors.add(ioDesc->mIoHandle, ioDesc);
-        ALOGV("ioConfigChanged() new %s opened %d samplingRate %u, format %#x channel mask %#x "
-                "frameCount %zu", event == AUDIO_OUTPUT_OPENED ? "output" : "input",
-                ioDesc->mIoHandle, ioDesc->mSamplingRate, ioDesc->mFormat, ioDesc->mChannelMask,
-                ioDesc->mFrameCount);
-        } break;
-    case AUDIO_OUTPUT_CLOSED:
-    case AUDIO_INPUT_CLOSED: {
-        if (getIoDescriptor(ioDesc->mIoHandle) == 0) {
-            ALOGW("ioConfigChanged() closing unknown %s %d",
+    {
+        Mutex::Autolock _l(mLock);
+
+        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;
+            }
+            mIoDescriptors.add(ioDesc->mIoHandle, ioDesc);
+
+            if (ioDesc->getDeviceId() != AUDIO_PORT_HANDLE_NONE) {
+                deviceId = ioDesc->getDeviceId();
+                ssize_t ioIndex = mAudioDeviceCallbacks.indexOfKey(ioDesc->mIoHandle);
+                if (ioIndex >= 0) {
+                    callbacks = mAudioDeviceCallbacks.valueAt(ioIndex);
+                }
+            }
+            ALOGV("ioConfigChanged() new %s opened %d samplingRate %u, format %#x channel mask %#x "
+                    "frameCount %zu deviceId %d", event == AUDIO_OUTPUT_OPENED ? "output" : "input",
+                    ioDesc->mIoHandle, ioDesc->mSamplingRate, ioDesc->mFormat, ioDesc->mChannelMask,
+                    ioDesc->mFrameCount, ioDesc->getDeviceId());
+            } break;
+        case AUDIO_OUTPUT_CLOSED:
+        case AUDIO_INPUT_CLOSED: {
+            if (getIoDescriptor(ioDesc->mIoHandle) == 0) {
+                ALOGW("ioConfigChanged() closing unknown %s %d",
+                      event == AUDIO_OUTPUT_CLOSED ? "output" : "input", ioDesc->mIoHandle);
+                break;
+            }
+            ALOGV("ioConfigChanged() %s %d closed",
                   event == AUDIO_OUTPUT_CLOSED ? "output" : "input", ioDesc->mIoHandle);
-            break;
-        }
-        ALOGV("ioConfigChanged() %s %d closed", event == AUDIO_OUTPUT_CLOSED ? "output" : "input",
-                ioDesc->mIoHandle);
 
-        mIoDescriptors.removeItem(ioDesc->mIoHandle);
-        } break;
+            mIoDescriptors.removeItem(ioDesc->mIoHandle);
+            mAudioDeviceCallbacks.removeItem(ioDesc->mIoHandle);
+            } break;
 
-    case AUDIO_OUTPUT_CONFIG_CHANGED:
-    case AUDIO_INPUT_CONFIG_CHANGED: {
-        if (getIoDescriptor(ioDesc->mIoHandle) == 0) {
-            ALOGW("ioConfigChanged() modifying unknown output! %d", ioDesc->mIoHandle);
-            break;
+        case AUDIO_OUTPUT_CONFIG_CHANGED:
+        case AUDIO_INPUT_CONFIG_CHANGED: {
+            sp<AudioIoDescriptor> oldDesc = getIoDescriptor(ioDesc->mIoHandle);
+            if (oldDesc == 0) {
+                ALOGW("ioConfigChanged() modifying unknown output! %d", ioDesc->mIoHandle);
+                break;
+            }
+
+            deviceId = oldDesc->getDeviceId();
+            mIoDescriptors.replaceValueFor(ioDesc->mIoHandle, ioDesc);
+
+            if (deviceId != ioDesc->getDeviceId()) {
+                deviceId = ioDesc->getDeviceId();
+                ssize_t ioIndex = mAudioDeviceCallbacks.indexOfKey(ioDesc->mIoHandle);
+                if (ioIndex >= 0) {
+                    callbacks = mAudioDeviceCallbacks.valueAt(ioIndex);
+                }
+            }
+            ALOGV("ioConfigChanged() new config for %s %d samplingRate %u, format %#x "
+                    "channel mask %#x frameCount %zu deviceId %d",
+                    event == AUDIO_OUTPUT_CONFIG_CHANGED ? "output" : "input",
+                    ioDesc->mIoHandle, ioDesc->mSamplingRate, ioDesc->mFormat,
+                    ioDesc->mChannelMask, ioDesc->mFrameCount, ioDesc->getDeviceId());
+
+        } break;
         }
-        mIoDescriptors.replaceValueFor(ioDesc->mIoHandle, ioDesc);
-        ALOGV("ioConfigChanged() new config for %s %d samplingRate %u, format %#x "
-                "channel mask %#x frameCount %zu",
-                event == AUDIO_OUTPUT_CONFIG_CHANGED ? "output" : "input",
-                ioDesc->mIoHandle, ioDesc->mSamplingRate, ioDesc->mFormat,
-                ioDesc->mChannelMask, ioDesc->mFrameCount);
-    } break;
+    }
+    // callbacks.size() != 0 =>  ioDesc->mIoHandle and deviceId are valid
+    for (size_t i = 0; i < callbacks.size(); i++) {
+        callbacks[i]->onAudioDeviceUpdate(ioDesc->mIoHandle, deviceId);
     }
 }
 
@@ -532,7 +576,56 @@ sp<AudioIoDescriptor> AudioSystem::AudioFlingerClient::getIoDescriptor(audio_io_
     return desc;
 }
 
-/*static*/ void AudioSystem::setErrorCallback(audio_error_callback cb)
+status_t AudioSystem::AudioFlingerClient::addAudioDeviceCallback(
+        const sp<AudioDeviceCallback>& callback, audio_io_handle_t audioIo)
+{
+    Mutex::Autolock _l(mLock);
+    Vector < sp<AudioDeviceCallback> > callbacks;
+    ssize_t ioIndex = mAudioDeviceCallbacks.indexOfKey(audioIo);
+    if (ioIndex >= 0) {
+        callbacks = mAudioDeviceCallbacks.valueAt(ioIndex);
+    }
+
+    for (size_t cbIndex = 0; cbIndex < callbacks.size(); cbIndex++) {
+        if (callbacks[cbIndex] == callback) {
+            return INVALID_OPERATION;
+        }
+    }
+    callbacks.add(callback);
+
+    mAudioDeviceCallbacks.replaceValueFor(audioIo, callbacks);
+    return NO_ERROR;
+}
+
+status_t AudioSystem::AudioFlingerClient::removeAudioDeviceCallback(
+        const sp<AudioDeviceCallback>& callback, audio_io_handle_t audioIo)
+{
+    Mutex::Autolock _l(mLock);
+    ssize_t ioIndex = mAudioDeviceCallbacks.indexOfKey(audioIo);
+    if (ioIndex < 0) {
+        return INVALID_OPERATION;
+    }
+    Vector < sp<AudioDeviceCallback> > callbacks = mAudioDeviceCallbacks.valueAt(ioIndex);
+
+    size_t cbIndex;
+    for (cbIndex = 0; cbIndex < callbacks.size(); cbIndex++) {
+        if (callbacks[cbIndex] == callback) {
+            break;
+        }
+    }
+    if (cbIndex == callbacks.size()) {
+        return INVALID_OPERATION;
+    }
+    callbacks.removeAt(cbIndex);
+    if (callbacks.size() != 0) {
+        mAudioDeviceCallbacks.replaceValueFor(audioIo, callbacks);
+    } else {
+        mAudioDeviceCallbacks.removeItem(audioIo);
+    }
+    return NO_ERROR;
+}
+
+/* static */ void AudioSystem::setErrorCallback(audio_error_callback cb)
 {
     Mutex::Autolock _l(gLock);
     gAudioErrorCallback = cb;
@@ -864,11 +957,11 @@ void AudioSystem::clearAudioConfigCache()
 {
     // called by restoreTrack_l(), which needs new IAudioFlinger and IAudioPolicyService instances
     ALOGV("clearAudioConfigCache()");
-    if (gAudioFlingerClient != 0) {
-        gAudioFlingerClient->clearIoCache();
-    }
     {
         Mutex::Autolock _l(gLock);
+        if (gAudioFlingerClient != 0) {
+            gAudioFlingerClient->clearIoCache();
+        }
         gAudioFlinger.clear();
     }
     {
@@ -934,7 +1027,7 @@ status_t AudioSystem::setAudioPortConfig(const struct audio_port_config *config)
     return aps->setAudioPortConfig(config);
 }
 
-status_t AudioSystem::addAudioPortCallback(const sp<AudioPortCallback>& callBack)
+status_t AudioSystem::addAudioPortCallback(const sp<AudioPortCallback>& callback)
 {
     const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();
     if (aps == 0) return PERMISSION_DENIED;
@@ -943,11 +1036,11 @@ status_t AudioSystem::addAudioPortCallback(const sp<AudioPortCallback>& callBack
     if (gAudioPolicyServiceClient == 0) {
         return NO_INIT;
     }
-    return gAudioPolicyServiceClient->addAudioPortCallback(callBack);
+    return gAudioPolicyServiceClient->addAudioPortCallback(callback);
 }
 
 /*static*/
-status_t AudioSystem::removeAudioPortCallback(const sp<AudioPortCallback>& callBack)
+status_t AudioSystem::removeAudioPortCallback(const sp<AudioPortCallback>& callback)
 {
     const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();
     if (aps == 0) return PERMISSION_DENIED;
@@ -956,7 +1049,38 @@ status_t AudioSystem::removeAudioPortCallback(const sp<AudioPortCallback>& callB
     if (gAudioPolicyServiceClient == 0) {
         return NO_INIT;
     }
-    return gAudioPolicyServiceClient->removeAudioPortCallback(callBack);
+    return gAudioPolicyServiceClient->removeAudioPortCallback(callback);
+}
+
+status_t AudioSystem::addAudioDeviceCallback(
+        const sp<AudioDeviceCallback>& callback, audio_io_handle_t audioIo)
+{
+    const sp<AudioFlingerClient> afc = getAudioFlingerClient();
+    if (afc == 0) {
+        return NO_INIT;
+    }
+    return afc->addAudioDeviceCallback(callback, audioIo);
+}
+
+status_t AudioSystem::removeAudioDeviceCallback(
+        const sp<AudioDeviceCallback>& callback, audio_io_handle_t audioIo)
+{
+    const sp<AudioFlingerClient> afc = getAudioFlingerClient();
+    if (afc == 0) {
+        return NO_INIT;
+    }
+    return afc->removeAudioDeviceCallback(callback, audioIo);
+}
+
+audio_port_handle_t AudioSystem::getDeviceIdForIo(audio_io_handle_t audioIo)
+{
+    const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
+    if (af == 0) return PERMISSION_DENIED;
+    const sp<AudioIoDescriptor> desc = getIoDescriptor(audioIo);
+    if (desc == 0) {
+        return AUDIO_PORT_HANDLE_NONE;
+    }
+    return desc->getDeviceId();
 }
 
 status_t AudioSystem::acquireSoundTriggerSession(audio_session_t *session,
@@ -1008,25 +1132,25 @@ status_t AudioSystem::stopAudioSource(audio_io_handle_t handle)
 // ---------------------------------------------------------------------------
 
 status_t AudioSystem::AudioPolicyServiceClient::addAudioPortCallback(
-        const sp<AudioPortCallback>& callBack)
+        const sp<AudioPortCallback>& callback)
 {
     Mutex::Autolock _l(mLock);
     for (size_t i = 0; i < mAudioPortCallbacks.size(); i++) {
-        if (mAudioPortCallbacks[i] == callBack) {
+        if (mAudioPortCallbacks[i] == callback) {
             return INVALID_OPERATION;
         }
     }
-    mAudioPortCallbacks.add(callBack);
+    mAudioPortCallbacks.add(callback);
     return NO_ERROR;
 }
 
 status_t AudioSystem::AudioPolicyServiceClient::removeAudioPortCallback(
-        const sp<AudioPortCallback>& callBack)
+        const sp<AudioPortCallback>& callback)
 {
     Mutex::Autolock _l(mLock);
     size_t i;
     for (i = 0; i < mAudioPortCallbacks.size(); i++) {
-        if (mAudioPortCallbacks[i] == callBack) {
+        if (mAudioPortCallbacks[i] == callback) {
             break;
         }
     }
@@ -1037,6 +1161,7 @@ status_t AudioSystem::AudioPolicyServiceClient::removeAudioPortCallback(
     return NO_ERROR;
 }
 
+
 void AudioSystem::AudioPolicyServiceClient::onAudioPortListUpdate()
 {
     Mutex::Autolock _l(mLock);
diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp
index bb47d3e..db316b0 100644
--- a/media/libmedia/AudioTrack.cpp
+++ b/media/libmedia/AudioTrack.cpp
@@ -234,6 +234,10 @@ AudioTrack::~AudioTrack()
             mAudioTrackThread->requestExitAndWait();
             mAudioTrackThread.clear();
         }
+        // No lock here: worst case we remove a NULL callback which will be a nop
+        if (mDeviceCallback != 0 && mOutput != AUDIO_IO_HANDLE_NONE) {
+            AudioSystem::removeAudioDeviceCallback(mDeviceCallback, mOutput);
+        }
         IInterface::asBinder(mAudioTrack)->unlinkToDeath(mDeathNotifier, this);
         mAudioTrack.clear();
         mCblkMemory.clear();
@@ -1042,6 +1046,14 @@ audio_port_handle_t AudioTrack::getOutputDevice() {
     return mSelectedDeviceId;
 }
 
+audio_port_handle_t AudioTrack::getRoutedDeviceId() {
+    AutoMutex lock(mLock);
+    if (mOutput == AUDIO_IO_HANDLE_NONE) {
+        return AUDIO_PORT_HANDLE_NONE;
+    }
+    return AudioSystem::getDeviceIdForIo(mOutput);
+}
+
 status_t AudioTrack::attachAuxEffect(int effectId)
 {
     AutoMutex lock(mLock);
@@ -1071,6 +1083,9 @@ status_t AudioTrack::createTrack_l()
         return NO_INIT;
     }
 
+    if (mDeviceCallback != 0 && mOutput != AUDIO_IO_HANDLE_NONE) {
+        AudioSystem::removeAudioDeviceCallback(mDeviceCallback, mOutput);
+    }
     audio_io_handle_t output;
     audio_stream_type_t streamType = mStreamType;
     audio_attributes_t *attr = (mStreamType == AUDIO_STREAM_DEFAULT) ? &mAttributes : NULL;
@@ -1375,6 +1390,10 @@ status_t AudioTrack::createTrack_l()
     mDeathNotifier = new DeathNotifier(this);
     IInterface::asBinder(mAudioTrack)->linkToDeath(mDeathNotifier, this);
 
+    if (mDeviceCallback != 0) {
+        AudioSystem::addAudioDeviceCallback(mDeviceCallback, mOutput);
+    }
+
     return NO_ERROR;
     }
 
@@ -2308,6 +2327,48 @@ uint32_t AudioTrack::getUnderrunFrames() const
     return mProxy->getUnderrunFrames();
 }
 
+status_t AudioTrack::addAudioDeviceCallback(const sp<AudioSystem::AudioDeviceCallback>& callback)
+{
+    if (callback == 0) {
+        ALOGW("%s adding NULL callback!", __FUNCTION__);
+        return BAD_VALUE;
+    }
+    AutoMutex lock(mLock);
+    if (mDeviceCallback == callback) {
+        ALOGW("%s adding same callback!", __FUNCTION__);
+        return INVALID_OPERATION;
+    }
+    status_t status = NO_ERROR;
+    if (mOutput != AUDIO_IO_HANDLE_NONE) {
+        if (mDeviceCallback != 0) {
+            ALOGW("%s callback already present!", __FUNCTION__);
+            AudioSystem::removeAudioDeviceCallback(mDeviceCallback, mOutput);
+        }
+        status = AudioSystem::addAudioDeviceCallback(callback, mOutput);
+    }
+    mDeviceCallback = callback;
+    return status;
+}
+
+status_t AudioTrack::removeAudioDeviceCallback(
+        const sp<AudioSystem::AudioDeviceCallback>& callback)
+{
+    if (callback == 0) {
+        ALOGW("%s removing NULL callback!", __FUNCTION__);
+        return BAD_VALUE;
+    }
+    AutoMutex lock(mLock);
+    if (mDeviceCallback != callback) {
+        ALOGW("%s removing different callback!", __FUNCTION__);
+        return INVALID_OPERATION;
+    }
+    if (mOutput != AUDIO_IO_HANDLE_NONE) {
+        AudioSystem::removeAudioDeviceCallback(mDeviceCallback, mOutput);
+    }
+    mDeviceCallback = 0;
+    return NO_ERROR;
+}
+
 // =========================================================================
 
 void AudioTrack::DeathNotifier::binderDied(const wp<IBinder>& who __unused)
diff --git a/media/libmedia/IAudioFlingerClient.cpp b/media/libmedia/IAudioFlingerClient.cpp
index a622241..3429d36 100644
--- a/media/libmedia/IAudioFlingerClient.cpp
+++ b/media/libmedia/IAudioFlingerClient.cpp
@@ -45,6 +45,7 @@ public:
         data.writeInterfaceToken(IAudioFlingerClient::getInterfaceDescriptor());
         data.writeInt32(event);
         data.writeInt32((int32_t)ioDesc->mIoHandle);
+        data.write(&ioDesc->mPatch, sizeof(struct audio_patch));
         data.writeInt32(ioDesc->mSamplingRate);
         data.writeInt32(ioDesc->mFormat);
         data.writeInt32(ioDesc->mChannelMask);
@@ -67,6 +68,7 @@ status_t BnAudioFlingerClient::onTransact(
             audio_io_config_event event = (audio_io_config_event)data.readInt32();
             sp<AudioIoDescriptor> ioDesc = new AudioIoDescriptor();
             ioDesc->mIoHandle = (audio_io_handle_t) data.readInt32();
+            data.read(&ioDesc->mPatch, sizeof(struct audio_patch));
             ioDesc->mSamplingRate = data.readInt32();
             ioDesc->mFormat = (audio_format_t) data.readInt32();
             ioDesc->mChannelMask = (audio_channel_mask_t) data.readInt32();