commit 85ba33303cd87f81b2c1c7e157781e1ca8e7296c
author Andy Hung <hunga@google.com> Tue Apr 27 17:40:26 2021 -0700
committer Andy Hung <hunga@google.com> Wed Apr 28 10:09:24 2021 -0700
tree 421da22cce1c66970e1e892d5a161020b6b70517
parent 86fec3ec4894e438f550365bfeaa756b4d571db0

AudioFlinger: Do not send down 0's on direct PCM track underrun

Without HW pause, 0's were sent down in direct PCM track underrun.
This might be OK for linear PCM, but for proportional/encapsulated
PCM data this is not acceptable.  We avoid adding any 0's.

Test: directed test (see b/186596553)
Bug: 34711969
Bug: 157682459
Bug: 161089206
Bug: 186596553
Change-Id: I398915d11c5a3c2e8775c68ca7717cd9f826ecf1

services/audioflinger/Threads.cpp

diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index ef92492..e964a09 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -6115,16 +6115,13 @@
         mSleepTimeUs = mIdleSleepTimeUs;
         return;
     }
-    if (mSleepTimeUs == 0) {
-        if (mMixerStatus == MIXER_TRACKS_ENABLED) {
-            mSleepTimeUs = mActiveSleepTimeUs;
-        } else {
-            mSleepTimeUs = mIdleSleepTimeUs;
-        }
-    } else if (mBytesWritten != 0 && audio_has_proportional_frames(mFormat)) {
-        memset(mSinkBuffer, 0, mFrameCount * mFrameSize);
-        mSleepTimeUs = 0;
+    if (mMixerStatus == MIXER_TRACKS_ENABLED) {
+        mSleepTimeUs = mActiveSleepTimeUs;
+    } else {
+        mSleepTimeUs = mIdleSleepTimeUs;
     }
+    // Note: In S or later, we do not write zeroes for
+    // linear or proportional PCM direct tracks in underrun.
 }
 
 void AudioFlinger::DirectOutputThread::threadLoop_exit()