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Commit 54464ba8 authored by Glenn Kasten's avatar Glenn Kasten Committed by Rachad Alao
Browse files

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: I96252782911bd42a2534cc4030521b7eeb99a7b9
parent a67ced97

services/audioflinger/Threads.cpp

+13 −0
Original line number Diff line number Diff line
@@ -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;

            }

        }
@@ -3091,6 +3092,18 @@ 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()

services/audioflinger/Threads.h

+1 −0
Original line number Diff line number Diff line
@@ -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

services/audioflinger/Tracks.cpp

+9 −1
Original line number Diff line number Diff line
@@ -894,7 +894,15 @@ 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;