AudioFlinger: Modify flush handling for offload path

Do not allow an offload track to directly control the offload thread
behavior. OffloadThread can check for any pending flush reporting
by its active tracks and decide to flush the HW or not.

Bug: 12530661
Change-Id: Ib33f023c942f6c091b618004136b153c38a6eef6

4 files changed, 31 insertions, 15 deletions

diff --git a/services/audioflinger/PlaybackTracks.h b/services/audioflinger/PlaybackTracks.h
index 4b6c74d..6600161 100644
--- a/services/audioflinger/PlaybackTracks.h
+++ b/services/audioflinger/PlaybackTracks.h
@@ -94,6 +94,8 @@ protected:
     bool isReady() const;
     void setPaused() { mState = PAUSED; }
     void reset();
+    bool isFlushPending() const { return mFlushHwPending; }
+    void flushAck();
 
     bool isOutputTrack() const {
         return (mStreamType == AUDIO_STREAM_CNT);
@@ -155,6 +157,7 @@ private:
     bool                mIsInvalid; // non-resettable latch, set by invalidate()
     AudioTrackServerProxy*  mAudioTrackServerProxy;
     bool                mResumeToStopping; // track was paused in stopping state.
+    bool                mFlushHwPending; // track requests for thread flush
 };  // end of Track
 
 class TimedTrack : public Track {
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 00d14e8..cecb3dc 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -2727,12 +2727,6 @@ void AudioFlinger::MixerThread::threadLoop_standby()
     PlaybackThread::threadLoop_standby();
 }
 
-// Empty implementation for standard mixer
-// Overridden for offloaded playback
-void AudioFlinger::PlaybackThread::flushOutput_l()
-{
-}
-
 bool AudioFlinger::PlaybackThread::waitingAsyncCallback_l()
 {
     return false;
@@ -4003,6 +3997,17 @@ AudioFlinger::PlaybackThread::mixer_state AudioFlinger::OffloadThread::prepareTr
         sp<Track> l = mLatestActiveTrack.promote();
         bool last = l.get() == track;
 
+        if (track->isInvalid()) {
+            ALOGW("An invalidated track shouldn't be in active list");
+            tracksToRemove->add(track);
+            continue;
+        }
+
+        if (track->mState == TrackBase::IDLE) {
+            ALOGW("An idle track shouldn't be in active list");
+            continue;
+        }
+
         if (track->isPausing()) {
             track->setPaused();
             if (last) {
@@ -4021,6 +4026,11 @@ AudioFlinger::PlaybackThread::mixer_state AudioFlinger::OffloadThread::prepareTr
                 mBytesRemaining = 0;    // stop writing
             }
             tracksToRemove->add(track);
+        } else if (track->isFlushPending()) {
+            track->flushAck();
+            if (last) {
+                mFlushPending = true;
+            }
         } else if (track->framesReady() && track->isReady() &&
                 !track->isPaused() && !track->isTerminated() && !track->isStopping_2()) {
             ALOGVV("OffloadThread: track %d s=%08x [OK]", track->name(), cblk->mServer);
@@ -4161,11 +4171,6 @@ AudioFlinger::PlaybackThread::mixer_state AudioFlinger::OffloadThread::prepareTr
     return mixerStatus;
 }
 
-void AudioFlinger::OffloadThread::flushOutput_l()
-{
-    mFlushPending = true;
-}
-
 // must be called with thread mutex locked
 bool AudioFlinger::OffloadThread::waitingAsyncCallback_l()
 {
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 1745ea1..19289d2 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -631,7 +631,6 @@ public:
 protected:
                 // accessed by both binder threads and within threadLoop(), lock on mutex needed
                 unsigned    mFastTrackAvailMask;    // bit i set if fast track [i] is available
-    virtual     void        flushOutput_l();
 
 private:
     // timestamp latch:
@@ -750,7 +749,6 @@ protected:
     // threadLoop snippets
     virtual     mixer_state prepareTracks_l(Vector< sp<Track> > *tracksToRemove);
     virtual     void        threadLoop_exit();
-    virtual     void        flushOutput_l();
 
     virtual     bool        waitingAsyncCallback();
     virtual     bool        waitingAsyncCallback_l();
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index ecedca9..8ffa43e 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -347,7 +347,8 @@ AudioFlinger::PlaybackThread::Track::Track(
     mCachedVolume(1.0),
     mIsInvalid(false),
     mAudioTrackServerProxy(NULL),
-    mResumeToStopping(false)
+    mResumeToStopping(false),
+    mFlushHwPending(false)
 {
     if (mCblk != NULL) {
         if (sharedBuffer == 0) {
@@ -731,6 +732,7 @@ void AudioFlinger::PlaybackThread::Track::flush()
                 mRetryCount = PlaybackThread::kMaxTrackRetriesOffload;
             }
 
+            mFlushHwPending = true;
             mResumeToStopping = false;
         } else {
             if (mState != STOPPING_1 && mState != STOPPING_2 && mState != STOPPED &&
@@ -751,11 +753,19 @@ void AudioFlinger::PlaybackThread::Track::flush()
         // Prevent flush being lost if the track is flushed and then resumed
         // before mixer thread can run. This is important when offloading
         // because the hardware buffer could hold a large amount of audio
-        playbackThread->flushOutput_l();
         playbackThread->broadcast_l();
     }
 }
 
+// must be called with thread lock held
+void AudioFlinger::PlaybackThread::Track::flushAck()
+{
+    if (!isOffloaded())
+        return;
+
+    mFlushHwPending = false;
+}
+
 void AudioFlinger::PlaybackThread::Track::reset()
 {
     // Do not reset twice to avoid discarding data written just after a flush and before