AudioFlinger: offload playback, non-blocking write

- Added specialized playback thread class for offload playback,
derived from directoutput thread.
This thread type handles specific state transitions for offloaded
tracks and offloading commands (pause/resume/drain/flush..) to audio HAL.
As opposed to other threads, does not go to standby if the track is paused.

- Added support for asynchronous write and drain operations at audio HAL.
Use a thread to handle async callback events from HAL: this avoids locking
playback thread mutex when executing the callback and cause deadlocks when
calling audio HAL functions with the playback thread mutex locked.

- Better accouting for track activity: call start/stop and release Output
methods in audio policy manager when tracks are actually added and removed
from the active tracks list.
Added a command thread in audio policy service to handle stop/release commands
asynchronously and avoid deadlocks with playback thread.

- Track terminated status is not a state anymore. This condition is othogonal
to state to permitted state transitions while terminated.

Change-Id: Id157f4b3277620568d8eace7535d9186602564de

1 files changed, 18 insertions, 0 deletions

diff --git a/media/libmedia/AudioTrackShared.cpp b/media/libmedia/AudioTrackShared.cpp
index 55bf175..bd43ad2 100644
--- a/media/libmedia/AudioTrackShared.cpp
+++ b/media/libmedia/AudioTrackShared.cpp
@@ -322,6 +322,14 @@ void AudioTrackClientProxy::flush()
     mCblk->u.mStreaming.mFlush++;
 }
 
+bool AudioTrackClientProxy::clearStreamEndDone() {
+    return android_atomic_and(~CBLK_STREAM_END_DONE, &mCblk->flags) & CBLK_STREAM_END_DONE;
+}
+
+bool AudioTrackClientProxy::getStreamEndDone() const {
+    return (mCblk->flags & CBLK_STREAM_END_DONE) != 0;
+}
+
 // ---------------------------------------------------------------------------
 
 StaticAudioTrackClientProxy::StaticAudioTrackClientProxy(audio_track_cblk_t* cblk, void *buffers,
@@ -524,6 +532,16 @@ size_t AudioTrackServerProxy::framesReady()
     return filled;
 }
 
+bool  AudioTrackServerProxy::setStreamEndDone() {
+    bool old =
+            (android_atomic_or(CBLK_STREAM_END_DONE, &mCblk->flags) & CBLK_STREAM_END_DONE) != 0;
+    if (!old) {
+        (void) __futex_syscall3(&mCblk->mFutex, mClientInServer ? FUTEX_WAKE_PRIVATE : FUTEX_WAKE,
+                1);
+    }
+    return old;
+}
+
 // ---------------------------------------------------------------------------
 
 StaticAudioTrackServerProxy::StaticAudioTrackServerProxy(audio_track_cblk_t* cblk, void *buffers,