audioflinger: new HW A/V sync ID allocation flow

The HW A/V sync ID is now allocated by the audio HAL before the
output stream is created by a call to global get_parameters() with
key AUDIO_PARAMETER_HW_AV_SYNC.

When the AudioTrack is created, the HW A/V sync ID is communicated
to the output stream by stream set_parameters() with key
AUDIO_PARAMETER_STREAM_HW_AV_SYNC.

Bug: 17112525.
Change-Id: Ia8bc6f3bf9f358aa89f3f56ac554e893a19811ad

1 files changed, 57 insertions, 9 deletions

diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index e48af20..b6c365e 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -650,6 +650,7 @@ sp<IAudioTrack> AudioFlinger::createTrack(
             }
         }
 
+        setAudioHwSyncForSession_l(thread, (audio_session_t)lSessionId);
     }
 
     if (lStatus != NO_ERROR) {
@@ -1604,22 +1605,69 @@ status_t AudioFlinger::setLowRamDevice(bool isLowRamDevice)
 audio_hw_sync_t AudioFlinger::getAudioHwSyncForSession(audio_session_t sessionId)
 {
     Mutex::Autolock _l(mLock);
+
+    ssize_t index = mHwAvSyncIds.indexOfKey(sessionId);
+    if (index >= 0) {
+        ALOGV("getAudioHwSyncForSession found ID %d for session %d",
+              mHwAvSyncIds.valueAt(index), sessionId);
+        return mHwAvSyncIds.valueAt(index);
+    }
+
+    audio_hw_device_t *dev = mPrimaryHardwareDev->hwDevice();
+    if (dev == NULL) {
+        return AUDIO_HW_SYNC_INVALID;
+    }
+    char *reply = dev->get_parameters(dev, AUDIO_PARAMETER_HW_AV_SYNC);
+    AudioParameter param = AudioParameter(String8(reply));
+    free(reply);
+
+    int value;
+    if (param.getInt(String8(AUDIO_PARAMETER_HW_AV_SYNC), value) != NO_ERROR) {
+        ALOGW("getAudioHwSyncForSession error getting sync for session %d", sessionId);
+        return AUDIO_HW_SYNC_INVALID;
+    }
+
+    // allow only one session for a given HW A/V sync ID.
+    for (size_t i = 0; i < mHwAvSyncIds.size(); i++) {
+        if (mHwAvSyncIds.valueAt(i) == (audio_hw_sync_t)value) {
+            ALOGV("getAudioHwSyncForSession removing ID %d for session %d",
+                  value, mHwAvSyncIds.keyAt(i));
+            mHwAvSyncIds.removeItemsAt(i);
+            break;
+        }
+    }
+
+    mHwAvSyncIds.add(sessionId, value);
+
     for (size_t i = 0; i < mPlaybackThreads.size(); i++) {
         sp<PlaybackThread> thread = mPlaybackThreads.valueAt(i);
-        if ((thread->hasAudioSession(sessionId) & ThreadBase::TRACK_SESSION) != 0) {
-            // A session can only be on one thread, so exit after first match
-            String8 reply = thread->getParameters(String8(AUDIO_PARAMETER_STREAM_HW_AV_SYNC));
-            AudioParameter param = AudioParameter(reply);
-            int value;
-            if (param.getInt(String8(AUDIO_PARAMETER_STREAM_HW_AV_SYNC), value) == NO_ERROR) {
-                return value;
-            }
+        uint32_t sessions = thread->hasAudioSession(sessionId);
+        if (sessions & PlaybackThread::TRACK_SESSION) {
+            AudioParameter param = AudioParameter();
+            param.addInt(String8(AUDIO_PARAMETER_STREAM_HW_AV_SYNC), value);
+            thread->setParameters(param.toString());
             break;
         }
     }
-    return AUDIO_HW_SYNC_INVALID;
+
+    ALOGV("getAudioHwSyncForSession adding ID %d for session %d", value, sessionId);
+    return (audio_hw_sync_t)value;
 }
 
+// setAudioHwSyncForSession_l() must be called with AudioFlinger::mLock held
+void AudioFlinger::setAudioHwSyncForSession_l(PlaybackThread *thread, audio_session_t sessionId)
+{
+    ssize_t index = mHwAvSyncIds.indexOfKey(sessionId);
+    if (index >= 0) {
+        audio_hw_sync_t syncId = mHwAvSyncIds.valueAt(index);
+        ALOGV("setAudioHwSyncForSession_l found ID %d for session %d", syncId, sessionId);
+        AudioParameter param = AudioParameter();
+        param.addInt(String8(AUDIO_PARAMETER_STREAM_HW_AV_SYNC), syncId);
+        thread->setParameters(param.toString());
+    }
+}
+
+
 // ----------------------------------------------------------------------------