diff --git a/include/media/AudioSystem.h b/include/media/AudioSystem.h
index f8c0198..341f9ab 100644
--- a/include/media/AudioSystem.h
+++ b/include/media/AudioSystem.h
@@ -377,7 +377,10 @@
     friend class AudioFlingerClient;
     friend class AudioPolicyServiceClient;
 
-    static Mutex gLock;
+    static Mutex gLock;     // protects all members except gAudioPolicyService,
+                            // gAudioPolicyServiceClient, and gAudioPortCallback
+    static Mutex gLockAPS;  // protects gAudioPolicyService and gAudioPolicyServiceClient
+    static Mutex gLockAPC;  // protects gAudioPortCallback
     static sp<IAudioFlinger> gAudioFlinger;
     static audio_error_callback gAudioErrorCallback;