commit 9f6530f53ae9eda43f4e7c1cb30d2379db00aa00
author Eric Laurent <elaurent@google.com> Tue Aug 30 10:18:54 2011 -0700
committer Eric Laurent <elaurent@google.com> Tue Aug 30 10:19:38 2011 -0700
tree 663430f29fec8c038ad2770e2640c9480c0e2251
parent d2824a9a392e02a09929a34f0a3dad41ac1faacf

226483: A2DP connected, but music out to speaker

When the A2DP headset is connected, there is a possible
race condition when the audio tracks are moved from
the mixer thread attached to the speaker output to the thread
attached to A2DP output.
As the request to clear the stream type to output mapping cache in
the client process is asynchronous, it is possible that the flag
indicating to the client audio track to re-create the IAudioTrack
on the new thread is processed before the cache is invalidated.
In this case, the track will be attached to the old thread and
music will continue playing over the device speaker instead of being
redirected to A2DP headset.

Change-Id: Ib2ce1eb5320eaff83287b93779061bf4e7a330df

services/audioflinger/AudioFlinger.cpp

diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 744fa50..2260091 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -1362,6 +1362,7 @@
     for (int stream = 0; stream < AUDIO_STREAM_CNT; stream++) {
         mStreamTypes[stream].volume = mAudioFlinger->streamVolumeInternal(stream);
         mStreamTypes[stream].mute = mAudioFlinger->streamMute(stream);
+        mStreamTypes[stream].valid = true;
     }
 }
 
@@ -1530,6 +1531,14 @@
             chain->setStrategy(AudioSystem::getStrategyForStream((audio_stream_type_t)track->type()));
             chain->incTrackCnt();
         }
+
+        // invalidate track immediately if the stream type was moved to another thread since
+        // createTrack() was called by the client process.
+        if (!mStreamTypes[streamType].valid) {
+            LOGW("createTrack_l() on thread %p: invalidating track on stream %d",
+                 this, streamType);
+            android_atomic_or(CBLK_INVALID_ON, &track->mCblk->flags);
+        }
     }
     lStatus = NO_ERROR;
 
@@ -2219,6 +2228,14 @@
     }
 }
 
+void AudioFlinger::PlaybackThread::setStreamValid(int streamType, bool valid)
+{
+    LOGV ("PlaybackThread::setStreamValid() thread %p, streamType %d, valid %d",
+            this,  streamType, valid);
+    Mutex::Autolock _l(mLock);
+
+    mStreamTypes[streamType].valid = valid;
+}
 
 // getTrackName_l() must be called with ThreadBase::mLock held
 int AudioFlinger::MixerThread::getTrackName_l()
@@ -5074,11 +5091,14 @@
     LOGV("setStreamOutput() stream %d to output %d", stream, output);
     audioConfigChanged_l(AudioSystem::STREAM_CONFIG_CHANGED, output, &stream);
 
+    dstThread->setStreamValid(stream, true);
+
     for (size_t i = 0; i < mPlaybackThreads.size(); i++) {
         PlaybackThread *thread = mPlaybackThreads.valueAt(i).get();
         if (thread != dstThread &&
             thread->type() != ThreadBase::DIRECT) {
             MixerThread *srcThread = (MixerThread *)thread;
+            srcThread->setStreamValid(stream, false);
             srcThread->invalidateTracks(stream);
         }
     }