am 7eeaf3f0: Merge "AudioFlinger: refine mixer sleep time logic" into ics-mr1

* commit '7eeaf3f07aa6fb10639d9f96c1367eb98c3e8839':
  AudioFlinger: refine mixer sleep time logic

1 files changed, 6 insertions, 3 deletions

diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 697bcdf..5a46e44 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -1973,11 +1973,14 @@ bool AudioFlinger::MixerThread::threadLoop()
         if (LIKELY(mixerStatus == MIXER_TRACKS_READY)) {
             // mix buffers...
             mAudioMixer->process();
-            sleepTime = 0;
-            // increase sleep time progressively when application underrun condition clears
-            if (sleepTimeShift > 0) {
+            // increase sleep time progressively when application underrun condition clears.
+            // Only increase sleep time if the mixer is ready for two consecutive times to avoid
+            // that a steady state of alternating ready/not ready conditions keeps the sleep time
+            // such that we would underrun the audio HAL.
+            if ((sleepTime == 0) && (sleepTimeShift > 0)) {
                 sleepTimeShift--;
             }
+            sleepTime = 0;
             standbyTime = systemTime() + kStandbyTimeInNsecs;
             //TODO: delay standby when effects have a tail
         } else {