commit 4de95592980dba88a35b3dc8f3fd045588387a4f
author Eric Laurent <elaurent@google.com> Thu Sep 26 15:28:21 2013 -0700
committer Eric Laurent <elaurent@google.com> Thu Sep 26 15:56:43 2013 -0700
tree e871e1ad9318cdd21fe82eb6f44f687f366d1c60
parent 1802399c7c4d8557922688f246df292703f417f1

audioflinger: fix crash when starting offload thread

Passing a sp to parent thread to AsyncCallbackThread() constructor
causes a strong reference to be acquired on the OffloadThread inside
its constructor which causes an early launch of the thread loop
with unpredictable consequences.

Pass a wp to parent thread instead.

Also move the creation of the AsyncCallbackThread to
readOutputParameters() where mUseAsyncWrite is initialized which
makes more sense.

Also change the type of AsyncCallbackThread parent thread to PlaybackThread
instead of OffloadThread to allow a broder use of non blocking write which
in theory is not limited to audio offload use case.

Bug: 8174034.
Change-Id: I4b093b022030cd4f5eb8b8e477333e91098a6549

services/audioflinger/Threads.cpp

diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index b771e3b..2d9d485 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -1594,6 +1594,7 @@
         if (mOutput->stream->set_callback(mOutput->stream,
                                       AudioFlinger::PlaybackThread::asyncCallback, this) == 0) {
             mUseAsyncWrite = true;
+            mCallbackThread = new AudioFlinger::AsyncCallbackThread(this);
         }
     }
 
@@ -3746,9 +3747,9 @@
 // ----------------------------------------------------------------------------
 
 AudioFlinger::AsyncCallbackThread::AsyncCallbackThread(
-        const sp<AudioFlinger::OffloadThread>& offloadThread)
+        const wp<AudioFlinger::PlaybackThread>& playbackThread)
     :   Thread(false /*canCallJava*/),
-        mOffloadThread(offloadThread),
+        mPlaybackThread(playbackThread),
         mWriteAckSequence(0),
         mDrainSequence(0)
 {
@@ -3783,13 +3784,13 @@
             mDrainSequence &= ~1;
         }
         {
-            sp<AudioFlinger::OffloadThread> offloadThread = mOffloadThread.promote();
-            if (offloadThread != 0) {
+            sp<AudioFlinger::PlaybackThread> playbackThread = mPlaybackThread.promote();
+            if (playbackThread != 0) {
                 if (writeAckSequence & 1) {
-                    offloadThread->resetWriteBlocked(writeAckSequence >> 1);
+                    playbackThread->resetWriteBlocked(writeAckSequence >> 1);
                 }
                 if (drainSequence & 1) {
-                    offloadThread->resetDraining(drainSequence >> 1);
+                    playbackThread->resetDraining(drainSequence >> 1);
                 }
             }
         }
@@ -3847,7 +3848,6 @@
         mHwPaused(false),
         mPausedBytesRemaining(0)
 {
-    mCallbackThread = new AudioFlinger::AsyncCallbackThread(this);
 }
 
 AudioFlinger::OffloadThread::~OffloadThread()