Fix Vaapi VDA flush handling during resolution change

media/gpu/vaapi_video_decode_accelerator.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // This file contains an implementation of VideoDecoderAccelerator
 // that utilizes hardware video decoder present on Intel CPUs.
 
 #ifndef MEDIA_GPU_VAAPI_VIDEO_DECODE_ACCELERATOR_H_
 #define MEDIA_GPU_VAAPI_VIDEO_DECODE_ACCELERATOR_H_
 
@@ skipping 75 matching lines @@
  private:
   class VaapiH264Accelerator;
   class VaapiVP8Accelerator;
   class VaapiVP9Accelerator;
 
   // Notify the client that an error has occurred and decoding cannot continue.
   void NotifyError(Error error);
 
   // Map the received input buffer into this process' address space and
   // queue it for decode.
-  void MapAndQueueNewInputBuffer(const BitstreamBuffer& bitstream_buffer);
+  bool MapAndQueueNewInputBuffer(const BitstreamBuffer& bitstream_buffer);
 
   // Get a new input buffer from the queue and set it up in decoder. This will
   // sleep if no input buffers are available. Return true if a new buffer has
   // been set up, false if an early exit has been requested (due to initiated
   // reset/flush/destroy).
   bool GetInputBuffer_Locked();
 
   // Signal the client that the current buffer has been read and can be
   // returned. Will also release the mapping.
   void ReturnCurrInputBuffer_Locked();
 
   // Wait for more surfaces to become available. Return true once they do or
   // false if an early exit has been requested (due to an initiated
   // reset/flush/destroy).
   bool WaitForSurfaces_Locked();
 
+  bool IsFlushPending_Locked();
+
   // Continue decoding given input buffers and sleep waiting for input/output
   // as needed. Will exit if a new set of surfaces or reset/flush/destroy
   // is requested.
   void DecodeTask();
 
   // Scheduled after receiving a flush request and executed after the current
   // decoding task finishes decoding pending inputs. Makes the decoder return
   // all remaining output pictures and puts it in an idle state, ready
   // to resume if needed and schedules a FinishFlush.
   void FlushTask();
@@ skipping 66 matching lines @@
   scoped_refptr<VaapiDecodeSurface> CreateSurface();
 
   // VAVDA state.
   enum State {
     // Initialize() not called yet or failed.
     kUninitialized,
     // DecodeTask running.
     kDecoding,
     // Resetting, waiting for decoder to finish current task and cleanup.
     kResetting,
-    // Flushing, waiting for decoder to finish current task and cleanup.
-    kFlushing,
     // Idle, decoder in state ready to start/resume decoding.
     kIdle,
     // Destroying, waiting for the decoder to finish current task.
     kDestroying,
   };
 
   // Protects input buffer and surface queues and state_.
   base::Lock lock_;
   State state_;
   Config::OutputMode output_mode_;
 
   // An input buffer awaiting consumption, provided by the client.
   struct InputBuffer {
     InputBuffer();

[Owen Lin, 2017/01/19 07:39:16]

Remove both ctor and dtor?

[kcwu, 2017/01/20 07:49:03]

Done.

     ~InputBuffer();
 
-    int32_t id;
+    // Indicates this is a dummy buffer for flush request.
+    // If |dummy_flush| is true, |id| and |shm| are not used.
+    bool dummy_flush = false;
+
+    int32_t id = 0;
     std::unique_ptr<SharedMemoryRegion> shm;

[Owen Lin, 2017/01/19 07:39:16]

Why not just use "shm == null" to indicate an empty buffer?

[kcwu, 2017/01/19 08:26:10]

Do you mean "shm = null" to assign a default value? If so, it's unnecessary.

[Owen Lin, 2017/01/20 02:20:06]

No, I mean we don't really need a new member dummy_flush but using shm == null
to indicate an empty buffer. But it's really up to you.

[kcwu, 2017/01/20 07:49:03]

Done.

   };
 
   // Queue for available PictureBuffers (picture_buffer_ids).
   typedef std::queue<linked_ptr<InputBuffer>> InputBuffers;
   InputBuffers input_buffers_;
   // Signalled when input buffers are queued onto the input_buffers_ queue.
   base::ConditionVariable input_ready_;
 
   // Current input buffer at decoder.
   linked_ptr<InputBuffer> curr_input_buffer_;
@@ skipping 90 matching lines @@
 
   // The WeakPtrFactory for |weak_this_|.
   base::WeakPtrFactory<VaapiVideoDecodeAccelerator> weak_this_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VaapiVideoDecodeAccelerator);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_GPU_VAAPI_VIDEO_DECODE_ACCELERATOR_H_