diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index e8ca5ee..9b611d2 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -323,7 +323,8 @@
     mFlags(flags),
     mFastIndex(-1),
     mUnderrunCount(0),
-    mCachedVolume(1.0)
+    mCachedVolume(1.0),
+    mIsInvalid(false)
 {
     if (mCblk != NULL) {
         // to avoid leaking a track name, do not allocate one unless there is an mCblk
@@ -834,6 +835,14 @@
     return true;
 }
 
+void AudioFlinger::PlaybackThread::Track::invalidate()
+{
+    // FIXME should use proxy
+    android_atomic_or(CBLK_INVALID, &mCblk->flags);
+    mCblk->cv.signal();
+    mIsInvalid = true;
+}
+
 // ----------------------------------------------------------------------------
 
 sp<AudioFlinger::PlaybackThread::TimedTrack>