Fix uncertainty of one normal mix buffer in AudioTrack::getTimestamp
The per-thread timestamp latch was not synchronized with the per-track
released frames. Now the value of each track's released frames is
latched along with the timestamp.
Bug: 17531839
Bug: 17669342
Change-Id: I9d50c8c6a5de55a3f4561ac40e20d497376c1257
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 12e09ab..b1e9c07 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -2101,6 +2101,7 @@
// If an NBAIO sink is present, use it to write the normal mixer's submix
if (mNormalSink != 0) {
+
const size_t count = mBytesRemaining / mFrameSize;
ATRACE_BEGIN("write");
@@ -2126,6 +2127,7 @@
size_t totalFramesWritten = mNormalSink->framesWritten();
if (totalFramesWritten >= mLatchD.mTimestamp.mPosition) {
mLatchD.mUnpresentedFrames = totalFramesWritten - mLatchD.mTimestamp.mPosition;
+ // mLatchD.mFramesReleased is set immediately before D is clocked into Q
mLatchDValid = true;
}
}
@@ -2418,6 +2420,18 @@
logString = NULL;
}
+ // Gather the framesReleased counters for all active tracks,
+ // and latch them atomically with the timestamp.
+ // FIXME We're using raw pointers as indices. A unique track ID would be a better index.
+ mLatchD.mFramesReleased.clear();
+ 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());
+ }
+ }
if (mLatchDValid) {
mLatchQ = mLatchD;
mLatchDValid = false;
@@ -3093,6 +3107,7 @@
sleepTime = 0;
standbyTime = systemTime() + standbyDelay;
//TODO: delay standby when effects have a tail
+
}
void AudioFlinger::MixerThread::threadLoop_sleepTime()
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 7af5264..bb9aa18 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -819,8 +819,11 @@
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 mLatchDValid; // true means mLatchD is valid
+ // (except for mFramesReleased which is filled in later),
+ // 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..b9308fa 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -898,7 +898,16 @@
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;