V4L2VDA: do not allocate input buffers in GPU child thread.

media/gpu/v4l2_video_decode_accelerator.cc

Index: media/gpu/v4l2_video_decode_accelerator.cc
diff --git a/media/gpu/v4l2_video_decode_accelerator.cc b/media/gpu/v4l2_video_decode_accelerator.cc
index 1d5cf8ee6cb11d9b4e7222f4b08d7089e7f2b47e..3e761878946392861ea2e2a8f0b760e6478b1243 100644
--- a/media/gpu/v4l2_video_decode_accelerator.cc
+++ b/media/gpu/v4l2_video_decode_accelerator.cc
@@ -284,9 +284,6 @@ bool V4L2VideoDecodeAccelerator::Initialize(const Config& config,
     decoder_h264_parser_.reset(new H264Parser());
   }
 
-  if (!CreateInputBuffers())
-    return false;
-
   decoder_cmd_supported_ = IsDecoderCmdSupported();

[Pawel Osciak, 2016/11/24 08:28:35]

Could this and the subscribe event ioctl above be run on decoder thread as well?

[wuchengli, 2016/11/28 06:13:58]

Done.

 
   if (!decoder_thread_.Start()) {
@@ -294,18 +291,31 @@ bool V4L2VideoDecodeAccelerator::Initialize(const Config& config,
     return false;
   }
 
-  decoder_state_ = kInitialized;
   output_mode_ = config.output_mode;
 
-  // StartDevicePoll will NOTIFY_ERROR on failure, so IgnoreResult is fine here.
+  // InitializeTask will NOTIFY_ERROR on failure.
   decoder_thread_.task_runner()->PostTask(
-      FROM_HERE, base::Bind(base::IgnoreResult(
-                                &V4L2VideoDecodeAccelerator::StartDevicePoll),
+      FROM_HERE, base::Bind(&V4L2VideoDecodeAccelerator::InitializeTask,
                             base::Unretained(this)));
 
   return true;
 }
 
+void V4L2VideoDecodeAccelerator::InitializeTask() {
+  DVLOGF(3);
+  DCHECK(decoder_thread_.task_runner()->BelongsToCurrentThread());
+
+  if (!CreateInputBuffers()) {
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return;
+  }
+
+  if (!StartDevicePoll())

[Owen Lin, 2016/11/24 07:44:23]

Add a comment that StartDevicePoll with NOTIFY_ERROR, 

[wuchengli, 2016/11/24 08:20:09]

Two other StartDevicePoll doesn't have this comment. I'll keep the code as is to
be consistent.

+    return;
+
+  decoder_state_ = kInitialized;
+}
+
 void V4L2VideoDecodeAccelerator::Decode(
     const BitstreamBuffer& bitstream_buffer) {
   DVLOGF(1) << "input_id=" << bitstream_buffer.id()
@@ -2129,6 +2139,7 @@ gfx::Size V4L2VideoDecodeAccelerator::GetVisibleSize(
 
 bool V4L2VideoDecodeAccelerator::CreateInputBuffers() {
   DVLOGF(3);
+  DCHECK(decoder_thread_.task_runner()->BelongsToCurrentThread());
   // We always run this as we prepare to initialize.
   DCHECK_EQ(decoder_state_, kUninitialized);
   DCHECK(!input_streamon_);