reduce number of binder calls from mediaserver

Reduce the number of audio port, audio patch and
IO config changed binder calls from mediaserver to
client processes:
- Do not call IO config changed callback if selected
device is the same as previously selected one on a given
audio flinger playback or capture thread.
- Do not call the audio port or audo patch list update
callback on a client if this client as no listener registered.

Bug: 22045560.

Change-Id: If780e105404de79b7cb5c80c27b793ceb6b1c423

2 files changed, 32 insertions, 9 deletions

diff --git a/media/libmedia/AudioSystem.cpp b/media/libmedia/AudioSystem.cpp
index 6c2c226..f13bcf3 100644
--- a/media/libmedia/AudioSystem.cpp
+++ b/media/libmedia/AudioSystem.cpp
@@ -1043,7 +1043,11 @@ status_t AudioSystem::addAudioPortCallback(const sp<AudioPortCallback>& callback
     if (gAudioPolicyServiceClient == 0) {
         return NO_INIT;
     }
-    return gAudioPolicyServiceClient->addAudioPortCallback(callback);
+    int ret = gAudioPolicyServiceClient->addAudioPortCallback(callback);
+    if (ret == 1) {
+        aps->setAudioPortCallbacksEnabled(true);
+    }
+    return (ret < 0) ? INVALID_OPERATION : NO_ERROR;
 }
 
 /*static*/
@@ -1056,7 +1060,11 @@ status_t AudioSystem::removeAudioPortCallback(const sp<AudioPortCallback>& callb
     if (gAudioPolicyServiceClient == 0) {
         return NO_INIT;
     }
-    return gAudioPolicyServiceClient->removeAudioPortCallback(callback);
+    int ret = gAudioPolicyServiceClient->removeAudioPortCallback(callback);
+    if (ret == 0) {
+        aps->setAudioPortCallbacksEnabled(false);
+    }
+    return (ret < 0) ? INVALID_OPERATION : NO_ERROR;
 }
 
 status_t AudioSystem::addAudioDeviceCallback(
@@ -1138,20 +1146,20 @@ status_t AudioSystem::stopAudioSource(audio_io_handle_t handle)
 
 // ---------------------------------------------------------------------------
 
-status_t AudioSystem::AudioPolicyServiceClient::addAudioPortCallback(
+int AudioSystem::AudioPolicyServiceClient::addAudioPortCallback(
         const sp<AudioPortCallback>& callback)
 {
     Mutex::Autolock _l(mLock);
     for (size_t i = 0; i < mAudioPortCallbacks.size(); i++) {
         if (mAudioPortCallbacks[i] == callback) {
-            return INVALID_OPERATION;
+            return -1;
         }
     }
     mAudioPortCallbacks.add(callback);
-    return NO_ERROR;
+    return mAudioPortCallbacks.size();
 }
 
-status_t AudioSystem::AudioPolicyServiceClient::removeAudioPortCallback(
+int AudioSystem::AudioPolicyServiceClient::removeAudioPortCallback(
         const sp<AudioPortCallback>& callback)
 {
     Mutex::Autolock _l(mLock);
@@ -1162,10 +1170,10 @@ status_t AudioSystem::AudioPolicyServiceClient::removeAudioPortCallback(
         }
     }
     if (i == mAudioPortCallbacks.size()) {
-        return INVALID_OPERATION;
+        return -1;
     }
     mAudioPortCallbacks.removeAt(i);
-    return NO_ERROR;
+    return mAudioPortCallbacks.size();
 }
 
 
diff --git a/media/libmedia/IAudioPolicyService.cpp b/media/libmedia/IAudioPolicyService.cpp
index fd18f17..3348441 100644
--- a/media/libmedia/IAudioPolicyService.cpp
+++ b/media/libmedia/IAudioPolicyService.cpp
@@ -72,7 +72,8 @@ enum {
     GET_PHONE_STATE,
     REGISTER_POLICY_MIXES,
     START_AUDIO_SOURCE,
-    STOP_AUDIO_SOURCE
+    STOP_AUDIO_SOURCE,
+    SET_AUDIO_PORT_CALLBACK_ENABLED,
 };
 
 #define MAX_ITEMS_PER_LIST 1024
@@ -646,6 +647,14 @@ public:
         remote()->transact(REGISTER_CLIENT, data, &reply);
     }
 
+    virtual void setAudioPortCallbacksEnabled(bool enabled)
+    {
+        Parcel data, reply;
+        data.writeInterfaceToken(IAudioPolicyService::getInterfaceDescriptor());
+        data.writeInt32(enabled ? 1 : 0);
+        remote()->transact(SET_AUDIO_PORT_CALLBACK_ENABLED, data, &reply);
+    }
+
     virtual status_t acquireSoundTriggerSession(audio_session_t *session,
                                             audio_io_handle_t *ioHandle,
                                             audio_devices_t *device)
@@ -1219,6 +1228,12 @@ status_t BnAudioPolicyService::onTransact(
             return NO_ERROR;
         } break;
 
+        case SET_AUDIO_PORT_CALLBACK_ENABLED: {
+            CHECK_INTERFACE(IAudioPolicyService, data, reply);
+            setAudioPortCallbacksEnabled(data.readInt32() == 1);
+            return NO_ERROR;
+        } break;
+
         case ACQUIRE_SOUNDTRIGGER_SESSION: {
             CHECK_INTERFACE(IAudioPolicyService, data, reply);
             sp<IAudioPolicyServiceClient> client = interface_cast<IAudioPolicyServiceClient>(