diff --git a/media/libmedia/AudioTrackShared.cpp b/media/libmedia/AudioTrackShared.cpp
index 6a51a76..caa84fb 100644
--- a/media/libmedia/AudioTrackShared.cpp
+++ b/media/libmedia/AudioTrackShared.cpp
@@ -932,7 +932,7 @@
     return (ssize_t) mState.mPosition;
 }
 
-status_t StaticAudioTrackServerProxy::obtainBuffer(Buffer* buffer, bool ackFlush __unused)
+status_t StaticAudioTrackServerProxy::obtainBuffer(Buffer* buffer, bool ackFlush)
 {
     if (mIsShutdown) {
         buffer->mFrameCount = 0;
@@ -970,7 +970,9 @@
     // it is always larger or equal to avail.
     LOG_ALWAYS_FATAL_IF(mFramesReady < (int64_t) avail);
     buffer->mNonContig = mFramesReady == INT64_MAX ? SIZE_MAX : clampToSize(mFramesReady - avail);
-    mUnreleased = avail;
+    if (!ackFlush) {
+        mUnreleased = avail;
+    }
     return NO_ERROR;
 }
 
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index b3fac0b..0e24b52 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -715,6 +715,7 @@
             // But in this case we know the mixer thread (whether normal mixer or fast mixer)
             // isn't looking at this track yet:  we still hold the normal mixer thread lock,
             // and for fast tracks the track is not yet in the fast mixer thread's active set.
+            // For static tracks, this is used to acknowledge change in position or loop.
             ServerProxy::Buffer buffer;
             buffer.mFrameCount = 1;
             (void) mAudioTrackServerProxy->obtainBuffer(&buffer, true /*ackFlush*/);