Report underruns for fast tracks also

This fixes a regression that was introduced earlier
by commit 9f80dd223d83d9bb9077fb6baee056cee4eaf7e5
called "New control block for AudioTrack and AudioRecord".
That commit broke underrun reporting for fast tracks.

Also remove Track::mUnderrunCount, which counted the number of underrun
events, and was only used by dumpsys media.audio_flinger.

Now dumpsys media.audio_flinger reports the number of underrun frames,

Isolated underrun-related control block accesses via the proxy, so that
the server is not directly poking around in the control block.

The new proxy APIs are AudioTrackServerProxy::getUnderrunFrames() and
AudioTrackServerProxy::tallyUnderrunFrames().  getUnderrunFrames() returns
a rolling counter for streaming tracks, or zero for static buffer tracks
which never underrun, but do a kind of 'pause' at end of buffer.
tallyUnderrunFrames() increments the counter by a specified number of frames.

Change-Id: Ib31fd73eb17cbb23888ce3af8ff29f471f5bd5a2

3 files changed, 8 insertions, 16 deletions

diff --git a/services/audioflinger/PlaybackTracks.h b/services/audioflinger/PlaybackTracks.h
index 628f5af..5600411c 100644
--- a/services/audioflinger/PlaybackTracks.h
+++ b/services/audioflinger/PlaybackTracks.h
@@ -140,7 +140,6 @@ private:
                                     // but the slot is only used if track is active
     FastTrackUnderruns  mObservedUnderruns; // Most recently observed value of
                                     // mFastMixerDumpState.mTracks[mFastIndex].mUnderruns
-    uint32_t            mUnderrunCount; // Counter of total number of underruns, never reset
     volatile float      mCachedVolume;  // combined master volume and stream type volume;
                                         // 'volatile' means accessed without lock or
                                         // barrier, but is read/written atomically
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index d9c312e..0c1cc35 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -2739,8 +2739,10 @@ AudioFlinger::PlaybackThread::mixer_state AudioFlinger::MixerThread::prepareTrac
             track->mObservedUnderruns = underruns;
             // don't count underruns that occur while stopping or pausing
             // or stopped which can occur when flush() is called while active
-            if (!(track->isStopping() || track->isPausing() || track->isStopped())) {
-                track->mUnderrunCount += recentUnderruns;
+            if (!(track->isStopping() || track->isPausing() || track->isStopped()) &&
+                    recentUnderruns > 0) {
+                // FIXME fast mixer will pull & mix partial buffers, but we count as a full underrun
+                track->mAudioTrackServerProxy->tallyUnderrunFrames(recentUnderruns * mFrameCount);
             }
 
             // This is similar to the state machine for normal tracks,
@@ -3056,12 +3058,8 @@ AudioFlinger::PlaybackThread::mixer_state AudioFlinger::MixerThread::prepareTrac
                 mixerStatus = MIXER_TRACKS_READY;
             }
         } else {
-            // only implemented for normal tracks, not fast tracks
             if (framesReady < desiredFrames && !track->isStopped() && !track->isPaused()) {
-                // we missed desiredFrames whatever the actual number of frames missing was
-                cblk->u.mStreaming.mUnderrunFrames += desiredFrames;
-                // FIXME also wake futex so that underrun is noticed more quickly
-                (void) android_atomic_or(CBLK_UNDERRUN, &cblk->mFlags);
+                track->mAudioTrackServerProxy->tallyUnderrunFrames(desiredFrames);
             }
             // clear effect chain input buffer if an active track underruns to avoid sending
             // previous audio buffer again to effects
@@ -3086,7 +3084,6 @@ AudioFlinger::PlaybackThread::mixer_state AudioFlinger::MixerThread::prepareTrac
                     tracksToRemove->add(track);
                 }
             } else {
-                track->mUnderrunCount++;
                 // No buffers for this track. Give it a few chances to
                 // fill a buffer, then remove it from active list.
                 if (--(track->mRetryCount) <= 0) {
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index 1f75468..e676365 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -316,7 +316,6 @@ AudioFlinger::PlaybackThread::Track::Track(
     mPresentationCompleteFrames(0),
     mFlags(flags),
     mFastIndex(-1),
-    mUnderrunCount(0),
     mCachedVolume(1.0),
     mIsInvalid(false),
     mAudioTrackServerProxy(NULL),
@@ -389,7 +388,7 @@ void AudioFlinger::PlaybackThread::Track::destroy()
 /*static*/ void AudioFlinger::PlaybackThread::Track::appendDumpHeader(String8& result)
 {
     result.append("   Name Client Type Fmt Chn mask Session fCount S F SRate  "
-                  "L dB  R dB    Server Main buf  Aux Buf Flags Underruns\n");
+                  "L dB  R dB    Server Main buf  Aux Buf Flags UndFrmCnt\n");
 }
 
 void AudioFlinger::PlaybackThread::Track::dump(char* buffer, size_t size)
@@ -470,7 +469,7 @@ void AudioFlinger::PlaybackThread::Track::dump(char* buffer, size_t size)
             (int)mMainBuffer,
             (int)mAuxBuffer,
             mCblk->mFlags,
-            mUnderrunCount,
+            mAudioTrackServerProxy->getUnderrunFrames(),
             nowInUnderrun);
 }
 
@@ -489,10 +488,7 @@ status_t AudioFlinger::PlaybackThread::Track::getNextBuffer(
     buffer->frameCount = buf.mFrameCount;
     buffer->raw = buf.mRaw;
     if (buf.mFrameCount == 0) {
-        // only implemented so far for normal tracks, not fast tracks
-        mCblk->u.mStreaming.mUnderrunFrames += desiredFrames;
-        // FIXME also wake futex so that underrun is noticed more quickly
-        (void) android_atomic_or(CBLK_UNDERRUN, &mCblk->mFlags);
+        mAudioTrackServerProxy->tallyUnderrunFrames(desiredFrames);
     }
     return status;
 }