AudioMixer: Clear bufferProviders in correct order

Issue:
 While switching between clips with different track properties, when
earlier track is cleared, postDownMixerBufferProvider
tries to release a buffer to serverProxy instead of the original owner
i.e. downMixBufferProvider. This illegal releaseBuffer call to serverProxy
results in an assert in AudioTrackShared.
-In issue scenario, data flow path in AudioMixer is,
ServerProxy-->-->DownMixer-->PostDownMixer-->Resampler,
- Clear for downMixerBufferProvider ensures that all serverproxy
buffers are returned back.
-This also causes the postDownMixer to get connected with serverProxy.
-Hence on delete of postDownMixer illegal releaseBuffer for
serverProxy gets executed.
Fix:
Clear PostDownMixerBufferProvider before clearing DownMixerBufferProvider
to ensure that buffers are release to right owners.

Change-Id: I982366660d0a1e04be8cca6dabe758221dedf9b1

1 files changed, 5 insertions, 9 deletions

diff --git a/services/audioflinger/AudioMixer.cpp b/services/audioflinger/AudioMixer.cpp
index b830985..bc062e6 100644
--- a/services/audioflinger/AudioMixer.cpp
+++ b/services/audioflinger/AudioMixer.cpp
@@ -308,6 +308,11 @@ bool AudioMixer::setChannelMasks(int name,
 void AudioMixer::track_t::unprepareForDownmix() {
     ALOGV("AudioMixer::unprepareForDownmix(%p)", this);
 
+    if (mPostDownmixReformatBufferProvider != NULL) {
+        delete mPostDownmixReformatBufferProvider;
+        mPostDownmixReformatBufferProvider = NULL;
+        reconfigureBufferProviders();
+    }
     mDownmixRequiresFormat = AUDIO_FORMAT_INVALID;
     if (downmixerBufferProvider != NULL) {
         // this track had previously been configured with a downmixer, delete it
@@ -363,18 +368,9 @@ status_t AudioMixer::track_t::prepareForDownmix()
 
 void AudioMixer::track_t::unprepareForReformat() {
     ALOGV("AudioMixer::unprepareForReformat(%p)", this);
-    bool requiresReconfigure = false;
     if (mReformatBufferProvider != NULL) {
         delete mReformatBufferProvider;
         mReformatBufferProvider = NULL;
-        requiresReconfigure = true;
-    }
-    if (mPostDownmixReformatBufferProvider != NULL) {
-        delete mPostDownmixReformatBufferProvider;
-        mPostDownmixReformatBufferProvider = NULL;
-        requiresReconfigure = true;
-    }
-    if (requiresReconfigure) {
         reconfigureBufferProviders();
     }
 }