commit 10fd056c636861b9e45e3df8456c95a5ddbcc556
author Mikhail Naganov <mnaganov@google.com> Tue Aug 01 17:20:24 2017 -0700
committer Mikhail Naganov <mnaganov@google.com> Wed Aug 02 08:49:39 2017 -0700
tree 46757a1f84a0ace8c6527711654cee9df3d5887a
parent 80d070f5dfc00c82218e341acb71d47c4cdc5d2c

libaudiohal: When starting write, consider the stream buffer size

When starting writing into a stream, use the bigger value from
the requested bytes to write and the stream buffer size.

This fixes a corner case when offload playback starts close
to the end of the track, and then jumps to the middle.

Bug: 63979005
Test: checked HAL logs for the repro case,
  confirmed that Loopback, PM, YT, Camcoder, still work, also over BT

Change-Id: I924468619d2185fd679b739747c423babfb36ada

media/libaudiohal/StreamHalHidl.cpp

diff --git a/media/libaudiohal/StreamHalHidl.cpp b/media/libaudiohal/StreamHalHidl.cpp
index 176abee..0cafa36 100644
--- a/media/libaudiohal/StreamHalHidl.cpp
+++ b/media/libaudiohal/StreamHalHidl.cpp
@@ -47,7 +47,8 @@
 StreamHalHidl::StreamHalHidl(IStream *stream)
         : ConversionHelperHidl("Stream"),
           mStream(stream),
-          mHalThreadPriority(HAL_THREAD_PRIORITY_DEFAULT) {
+          mHalThreadPriority(HAL_THREAD_PRIORITY_DEFAULT),
+          mCachedBufferSize(0){
 
     // Instrument audio signal power logging.
     // Note: This assumes channel mask, format, and sample rate do not change after creation.
@@ -73,7 +74,11 @@
 
 status_t StreamHalHidl::getBufferSize(size_t *size) {
     if (!mStream) return NO_INIT;
-    return processReturn("getBufferSize", mStream->getBufferSize(), size);
+    status_t status = processReturn("getBufferSize", mStream->getBufferSize(), size);
+    if (status == OK) {
+        mCachedBufferSize = *size;
+    }
+    return status;
 }
 
 status_t StreamHalHidl::getChannelMask(audio_channel_mask_t *mask) {
@@ -202,6 +207,14 @@
     return OK;
 }
 
+status_t StreamHalHidl::getCachedBufferSize(size_t *size) {
+    if (mCachedBufferSize != 0) {
+        *size = mCachedBufferSize;
+        return OK;
+    }
+    return getBufferSize(size);
+}
+
 bool StreamHalHidl::requestHalThreadPriority(pid_t threadPid, pid_t threadId) {
     if (mHalThreadPriority == HAL_THREAD_PRIORITY_DEFAULT) {
         return true;
@@ -320,8 +333,19 @@
     }
 
     status_t status;
-    if (!mDataMQ && (status = prepareForWriting(bytes)) != OK) {
-        return status;
+    if (!mDataMQ) {
+        // In case if playback starts close to the end of a compressed track, the bytes
+        // that need to be written is less than the actual buffer size. Need to use
+        // full buffer size for the MQ since otherwise after seeking back to the middle
+        // data will be truncated.
+        size_t bufferSize;
+        if ((status = getCachedBufferSize(&bufferSize)) != OK) {
+            return status;
+        }
+        if (bytes > bufferSize) bufferSize = bytes;
+        if ((status = prepareForWriting(bufferSize)) != OK) {
+            return status;
+        }
     }
 
     status = callWriterThread(

media/libaudiohal/StreamHalHidl.h

diff --git a/media/libaudiohal/StreamHalHidl.h b/media/libaudiohal/StreamHalHidl.h
index a69cce8..d4ab943 100644
--- a/media/libaudiohal/StreamHalHidl.h
+++ b/media/libaudiohal/StreamHalHidl.h
@@ -102,6 +102,8 @@
     // The destructor automatically closes the stream.
     virtual ~StreamHalHidl();
 
+    status_t getCachedBufferSize(size_t *size);
+
     bool requestHalThreadPriority(pid_t threadPid, pid_t threadId);
 
     // mStreamPowerLog is used for audio signal power logging.
@@ -111,6 +113,7 @@
     const int HAL_THREAD_PRIORITY_DEFAULT = -1;
     IStream *mStream;
     int mHalThreadPriority;
+    size_t mCachedBufferSize;
 };
 
 class StreamOutHalHidl : public StreamOutHalInterface, public StreamHalHidl {