AudioSystem: add API to query audio HW sync source

Add a method to query from the audio HAL the HW sync
source used for a given audio session.
Modify audio policy to select a direct output with HW sync
when requested.

Bug: 16132368.

Change-Id: I03038f9188f2d389f8a5fd76a671854013a4513e

1 files changed, 18 insertions, 1 deletions

diff --git a/media/libmedia/IAudioFlinger.cpp b/media/libmedia/IAudioFlinger.cpp
index 5331fce..346a192 100644
--- a/media/libmedia/IAudioFlinger.cpp
+++ b/media/libmedia/IAudioFlinger.cpp
@@ -79,7 +79,8 @@ enum {
     CREATE_AUDIO_PATCH,
     RELEASE_AUDIO_PATCH,
     LIST_AUDIO_PATCHES,
-    SET_AUDIO_PORT_CONFIG
+    SET_AUDIO_PORT_CONFIG,
+    GET_AUDIO_HW_SYNC
 };
 
 class BpAudioFlinger : public BpInterface<IAudioFlinger>
@@ -883,6 +884,17 @@ public:
         }
         return status;
     }
+    virtual audio_hw_sync_t getAudioHwSyncForSession(audio_session_t sessionId)
+    {
+        Parcel data, reply;
+        data.writeInterfaceToken(IAudioFlinger::getInterfaceDescriptor());
+        data.writeInt32(sessionId);
+        status_t status = remote()->transact(GET_AUDIO_HW_SYNC, data, &reply);
+        if (status != NO_ERROR) {
+            return AUDIO_HW_SYNC_INVALID;
+        }
+        return (audio_hw_sync_t)reply.readInt32();
+    }
 };
 
 IMPLEMENT_META_INTERFACE(AudioFlinger, "android.media.IAudioFlinger");
@@ -1345,6 +1357,11 @@ status_t BnAudioFlinger::onTransact(
             reply->writeInt32(status);
             return NO_ERROR;
         } break;
+        case GET_AUDIO_HW_SYNC: {
+            CHECK_INTERFACE(IAudioFlinger, data, reply);
+            reply->writeInt32(getAudioHwSyncForSession((audio_session_t)data.readInt32()));
+            return NO_ERROR;
+        } break;
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }