diff --git a/services/audioflinger/MmapTracks.h b/services/audioflinger/MmapTracks.h
index a210a1b..6f546c3 100644
--- a/services/audioflinger/MmapTracks.h
+++ b/services/audioflinger/MmapTracks.h
@@ -43,6 +43,15 @@
      static void        appendDumpHeader(String8& result);
             void        appendDump(String8& result, bool active);
 
+                        // protected by MMapThread::mLock
+            void        setSilenced_l(bool silenced) { mSilenced = silenced;
+                                                       mSilencedNotified = false;}
+                        // protected by MMapThread::mLock
+            bool        isSilenced_l() const { return mSilenced; }
+                        // protected by MMapThread::mLock
+            bool        getAndSetSilencedNotified_l() { bool silencedNotified = mSilencedNotified;
+                                                        mSilencedNotified = true;
+                                                        return silencedNotified; }
 private:
     friend class MmapThread;
 
@@ -58,5 +67,7 @@
     virtual void onTimestamp(const ExtendedTimestamp &timestamp);
 
     pid_t mPid;
+    bool  mSilenced;            // protected by MMapThread::mLock
+    bool  mSilencedNotified;    // protected by MMapThread::mLock
 };  // end of Track