am 955e24d3: Merge "Fix uncertainty of one normal mix buffer in AudioTrack::getTimestamp" into lmp-dev

* commit '955e24d3a8e218d4711cabc6558781e095011132':
  Fix uncertainty of one normal mix buffer in AudioTrack::getTimestamp

3 files changed, 23 insertions, 1 deletions

diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 12e09ab..66edf45 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -2126,6 +2126,7 @@ ssize_t AudioFlinger::PlaybackThread::threadLoop_write()
             size_t totalFramesWritten = mNormalSink->framesWritten();
             if (totalFramesWritten >= mLatchD.mTimestamp.mPosition) {
                 mLatchD.mUnpresentedFrames = totalFramesWritten - mLatchD.mTimestamp.mPosition;
+                // mLatchD.mFramesReleased is set in threadloop_mix()
                 mLatchDValid = true;
             }
         }
@@ -3093,6 +3094,18 @@ void AudioFlinger::MixerThread::threadLoop_mix()
     sleepTime = 0;
     standbyTime = systemTime() + standbyDelay;
     //TODO: delay standby when effects have a tail
+
+    mLatchD.mFramesReleased.clear();
+    {
+        Mutex::Autolock _l(mLock);
+        size_t size = mActiveTracks.size();
+        for (size_t i = 0; i < size; i++) {
+            sp<Track> t = mActiveTracks[i].promote();
+            if (t != 0) {
+                mLatchD.mFramesReleased.add(t.get(), t->mAudioTrackServerProxy->framesReleased());
+            }
+        }
+    }
 }
 
 void AudioFlinger::MixerThread::threadLoop_sleepTime()
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 7af5264..7d3b854 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -819,6 +819,7 @@ private:
     struct {
         AudioTimestamp  mTimestamp;
         uint32_t        mUnpresentedFrames;
+        KeyedVector<Track *, uint32_t> mFramesReleased;
     } mLatchD, mLatchQ;
     bool mLatchDValid;  // true means mLatchD is valid, and clock it into latch at next opportunity
     bool mLatchQValid;  // true means mLatchQ is valid
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index 75190f3..b2d53cf 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -898,7 +898,15 @@ status_t AudioFlinger::PlaybackThread::Track::getTimestamp(AudioTimestamp& times
         uint32_t unpresentedFrames =
                 ((int64_t) playbackThread->mLatchQ.mUnpresentedFrames * mSampleRate) /
                 playbackThread->mSampleRate;
-        uint32_t framesWritten = mAudioTrackServerProxy->framesReleased();
+        // FIXME Since we're using a raw pointer as the key, it is theoretically possible
+        //       for a brand new track to share the same address as a recently destroyed
+        //       track, and thus for us to get the frames released of the wrong track.
+        //       It is unlikely that we would be able to call getTimestamp() so quickly
+        //       right after creating a new track.  Nevertheless, the index here should
+        //       be changed to something that is unique.  Or use a completely different strategy.
+        ssize_t i = playbackThread->mLatchQ.mFramesReleased.indexOfKey(this);
+        uint32_t framesWritten = i >= 0 ?
+                playbackThread->mLatchQ.mFramesReleased[i] : mAudioTrackServerProxy->framesReleased();
         bool checkPreviousTimestamp = mPreviousValid && framesWritten >= mPreviousFramesWritten;
         if (framesWritten < unpresentedFrames) {
             mPreviousValid = false;