commit 236664745fa22cffb26044073000ddad100b9ced
author Kuowei Li <kuowei.li@mediatek.com> Wed Jan 20 10:23:25 2021 +0800
committer Andy Hung <hunga@google.com> Fri Apr 09 09:32:39 2021 -0700
tree 64256edc2dac49da7a54b72a0db6a84cbbaf386f
parent f2efd2a673eb225f3728496b00dac9e8b58ac4e6

AudioFlinger: Fix direct output resource from being occupied for too long

When flush immediately follows pause, mState might be overwritten and not
processed. In this case, direct output will retry due to data underrun.
In the duration of retry, the ActiveCount in AudioPolicy will be
positive and user can't create new track.
Add isPausePending to make sure pause will be handled by the
direct output thread.

Test: Manual (see bug)
Test: Clarity MediaPlayer Offloaded with seek.
Bug: 175092336
Change-Id: Ief742d2ce44917da24885373a5770e47876bc3a5

services/audioflinger/PlaybackTracks.h

diff --git a/services/audioflinger/PlaybackTracks.h b/services/audioflinger/PlaybackTracks.h
index 472c359..9770054 100644
--- a/services/audioflinger/PlaybackTracks.h
+++ b/services/audioflinger/PlaybackTracks.h
@@ -217,6 +217,10 @@
     void flushAck();
     bool isResumePending();
     void resumeAck();
+    // For direct or offloaded tracks ensure that the pause state is acknowledged
+    // by the playback thread in case of an immediate flush.
+    bool isPausePending() const { return mPauseHwPending; }
+    void pauseAck();
     void updateTrackFrameInfo(int64_t trackFramesReleased, int64_t sinkFramesWritten,
             uint32_t halSampleRate, const ExtendedTimestamp &timeStamp);
 
@@ -312,6 +316,7 @@
     sp<AudioTrackServerProxy>  mAudioTrackServerProxy;
     bool                mResumeToStopping; // track was paused in stopping state.
     bool                mFlushHwPending; // track requests for thread flush
+    bool                mPauseHwPending = false; // direct/offload track request for thread pause
     audio_output_flags_t mFlags;
     // If the last track change was notified to the client with readAndClearHasChanged
     std::atomic_flag     mChangeNotified = ATOMIC_FLAG_INIT;

services/audioflinger/Threads.cpp

diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 0c66301..deb13af 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -5825,8 +5825,15 @@
         sp<Track> l = mActiveTracks.getLatest();
         bool last = l.get() == track;
 
-        if (track->isPausing()) {
-            track->setPaused();
+        if (track->isPausePending()) {
+            track->pauseAck();
+            // It is possible a track might have been flushed or stopped.
+            // Other operations such as flush pending might occur on the next prepare.
+            if (track->isPausing()) {
+                track->setPaused();
+            }
+            // Always perform pause, as an immediate flush will change
+            // the pause state to be no longer isPausing().
             if (mHwSupportsPause && last && !mHwPaused) {
                 doHwPause = true;
                 mHwPaused = true;
@@ -6368,8 +6375,15 @@
             continue;
         }
 
-        if (track->isPausing()) {
-            track->setPaused();
+        if (track->isPausePending()) {
+            track->pauseAck();
+            // It is possible a track might have been flushed or stopped.
+            // Other operations such as flush pending might occur on the next prepare.
+            if (track->isPausing()) {
+                track->setPaused();
+            }
+            // Always perform pause if last, as an immediate flush will change
+            // the pause state to be no longer isPausing().
             if (last) {
                 if (mHwSupportsPause && !mHwPaused) {
                     doHwPause = true;

services/audioflinger/Tracks.cpp

diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index fb43a6e..4353b3d 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -1177,6 +1177,9 @@
             mState = PAUSING;
             ALOGV("%s(%d): ACTIVE/RESUMING => PAUSING on thread %d",
                     __func__, mId, (int)mThreadIoHandle);
+            if (isOffloadedOrDirect()) {
+                mPauseHwPending = true;
+            }
             playbackThread->broadcast_l();
             break;
 
@@ -1264,6 +1267,11 @@
     mFlushHwPending = false;
 }
 
+void AudioFlinger::PlaybackThread::Track::pauseAck()
+{
+    mPauseHwPending = false;
+}
+
 void AudioFlinger::PlaybackThread::Track::reset()
 {
     // Do not reset twice to avoid discarding data written just after a flush and before