audioflinger: fix auxiliary effect attachment

Auxiliary effects (Reverb) are global effects and as such follow
the default rule which is to attach them to the output thread that
handles music streams by default. This causes a problem when several
threads are eligible to handle music streams as tracks can be attached
to either thread based on criteria unknown when teh effect is created.

The fix consists in moving the auxiliary effect if necessary when an
AudioTrack is attached to it and this track is not on the same
output thread.

Bug 6608561.

Change-Id: Ib32c3cabc731b2046aba728be1771982999c6069

2 files changed, 65 insertions, 0 deletions

diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index b78c6d1..abe0293 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -1106,6 +1106,20 @@ void AudioFlinger::removeClient_l(pid_t pid)
     mClients.removeItem(pid);
 }
 
+// getEffectThread_l() must be called with AudioFlinger::mLock held
+sp<AudioFlinger::PlaybackThread> AudioFlinger::getEffectThread_l(int sessionId, int EffectId)
+{
+    sp<PlaybackThread> thread;
+
+    for (size_t i = 0; i < mPlaybackThreads.size(); i++) {
+        if (mPlaybackThreads.valueAt(i)->getEffect(sessionId, EffectId) != 0) {
+            ALOG_ASSERT(thread == 0);
+            thread = mPlaybackThreads.valueAt(i);
+        }
+    }
+
+    return thread;
+}
 
 // ----------------------------------------------------------------------------
 
@@ -4677,6 +4691,47 @@ status_t AudioFlinger::PlaybackThread::Track::attachAuxEffect(int EffectId)
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
         PlaybackThread *playbackThread = (PlaybackThread *)thread.get();
+        sp<AudioFlinger> af = mClient->audioFlinger();
+
+        Mutex::Autolock _l(af->mLock);
+
+        sp<PlaybackThread> srcThread = af->getEffectThread_l(AUDIO_SESSION_OUTPUT_MIX, EffectId);
+        if (srcThread == 0) {
+            return INVALID_OPERATION;
+        }
+
+        if (EffectId != 0 && playbackThread != srcThread.get()) {
+            Mutex::Autolock _dl(playbackThread->mLock);
+            Mutex::Autolock _sl(srcThread->mLock);
+            sp<EffectChain> chain = srcThread->getEffectChain_l(AUDIO_SESSION_OUTPUT_MIX);
+            if (chain == 0) {
+                return INVALID_OPERATION;
+            }
+
+            sp<EffectModule> effect = chain->getEffectFromId_l(EffectId);
+            if (effect == 0) {
+                return INVALID_OPERATION;
+            }
+            srcThread->removeEffect_l(effect);
+            playbackThread->addEffect_l(effect);
+            // removeEffect_l() has stopped the effect if it was active so it must be restarted
+            if (effect->state() == EffectModule::ACTIVE ||
+                    effect->state() == EffectModule::STOPPING) {
+                effect->start();
+            }
+
+            sp<EffectChain> dstChain = effect->chain().promote();
+            if (dstChain == 0) {
+                srcThread->addEffect_l(effect);
+                return INVALID_OPERATION;
+            }
+            AudioSystem::unregisterEffect(effect->id());
+            AudioSystem::registerEffect(&effect->desc(),
+                                        srcThread->id(),
+                                        dstChain->strategy(),
+                                        AUDIO_SESSION_OUTPUT_MIX,
+                                        effect->id());
+        }
         status = playbackThread->attachAuxEffect(this, EffectId);
     }
     return status;
@@ -7645,6 +7700,12 @@ Exit:
     return handle;
 }
 
+sp<AudioFlinger::EffectModule> AudioFlinger::ThreadBase::getEffect(int sessionId, int effectId)
+{
+    Mutex::Autolock _l(mLock);
+    return getEffect_l(sessionId, effectId);
+}
+
 sp<AudioFlinger::EffectModule> AudioFlinger::ThreadBase::getEffect_l(int sessionId, int effectId)
 {
     sp<EffectChain> chain = getEffectChain_l(sessionId);
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 384306c..cfd718f 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -253,6 +253,7 @@ public:
                                         int listenerSession,
                                         sync_event_callback_t callBack,
                                         void *cookie);
+
 private:
                audio_mode_t getMode() const { return mMode; }
 
@@ -543,6 +544,7 @@ private:
                     // set audio mode to all effect chains
                     void setMode(audio_mode_t mode);
                     // get effect module with corresponding ID on specified audio session
+                    sp<AudioFlinger::EffectModule> getEffect(int sessionId, int effectId);
                     sp<AudioFlinger::EffectModule> getEffect_l(int sessionId, int effectId);
                     // add and effect module. Also creates the effect chain is none exists for
                     // the effects audio session
@@ -1287,6 +1289,8 @@ private:
               PlaybackThread *primaryPlaybackThread_l() const;
               uint32_t primaryOutputDevice_l() const;
 
+              sp<PlaybackThread> getEffectThread_l(int sessionId, int EffectId);
+
     // server side of the client's IAudioTrack
     class TrackHandle : public android::BnAudioTrack {
     public: