VDA implementation for Exynos, using V4L2

content/common/gpu/media/exynos_video_decode_accelerator.cc

+// 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.
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/videodev2.h>
+#include <poll.h>
+#include <sys/eventfd.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+
+#include "base/bind.h"
+#include "base/debug/trace_event.h"
+#include "base/message_loop.h"
+#include "base/message_loop_proxy.h"
+#include "base/shared_memory.h"
+#include "content/common/gpu/media/exynos_video_decode_accelerator.h"
+#include "content/common/gpu/media/h264_parser.h"
+#include "third_party/angle/include/GLES2/gl2.h"
+
+namespace content {
+
+#define EXYNOS_MFC_DEVICE "/dev/mfc-dec"
+#define EXYNOS_GSC_DEVICE "/dev/gsc1"
+#define EXYNOS_MALI_DRIVER "libmali.so"
+
+#define NOTIFY_ERROR(x)                                               \
+  do {                                                                \
+    SetDecoderState(kError);                                          \
+    LOG(ERROR) << "calling NotifyError(): " << x;                     \
+    NotifyError(x);                                                   \
+  } while (0)
+
+#define IOCTL_OR_ERROR_RETURN(fd, type, arg)                          \
+  do {                                                                \
+    if (ioctl(fd, type, arg) != 0) {                                  \
+      DPLOG(ERROR) << __func__ << "(): ioctl() failed: " << #type;    \
+      NOTIFY_ERROR(PLATFORM_FAILURE);                                 \
+      return;                                                         \
+    }                                                                 \
+  } while (0)
+
+#define IOCTL_OR_ERROR_RETURN_FALSE(fd, type, arg)                    \
+  do {                                                                \
+    if (ioctl(fd, type, arg) != 0) {                                  \
+      DPLOG(ERROR) << __func__ << "(): ioctl() failed: " << #type;    \
+      NOTIFY_ERROR(PLATFORM_FAILURE);                                 \
+      return false;                                                   \
+    }                                                                 \
+  } while (0)
+
+#define POSTSANDBOX_DLSYM(lib, func, type, name)                      \
+  func = reinterpret_cast<type>(dlsym(lib, name));                    \
+  if (func == NULL) {                                                 \
+    DPLOG(ERROR) << "PostSandboxInitialization(): failed to dlsym() " \
+                 << name << ": " << dlerror();                        \
+    return false;                                                     \
+  }
+
+struct ExynosVideoDecodeAccelerator::BitstreamBufferRef {
+  BitstreamBufferRef(
+      base::WeakPtr<Client>& client,
+      scoped_refptr<base::MessageLoopProxy>& client_message_loop_proxy,
+      base::SharedMemory* shm,
+      size_t size,
+      int32 input_id);
+  ~BitstreamBufferRef();
+  const base::WeakPtr<Client> client;
+  const scoped_refptr<base::MessageLoopProxy> client_message_loop_proxy;
+  const scoped_ptr<base::SharedMemory> shm;
+  const size_t size;
+  off_t bytes_used;
+  const int32 input_id;
+};
+
+struct ExynosVideoDecodeAccelerator::PictureBufferArrayRef {
+  PictureBufferArrayRef(EGLDisplay egl_display, EGLImageKHR egl_images[],
+                        int egl_image_fds[], int32 client_ids[],
+                        int egl_images_count);
+  ~PictureBufferArrayRef();
+  EGLDisplay const egl_display;
+  const scoped_ptr<EGLImageKHR[]> egl_images;
+  const scoped_ptr<int[]> egl_image_fds;
+  const scoped_ptr<int32[]> client_ids;
+  const int egl_images_count;

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

My point about vector<> was that if you used it you could avoid having an
explicit count at all.

[sheu, 2013/01/11 10:41:42]

Alright, I'll just fold it into an array-of-structs type.  Now that this class
def is out of the main header file, I feel a little less bad about defining a
nested struct for it :-)

+};
+
+struct ExynosVideoDecodeAccelerator::EGLSyncKHRRef {
+  EGLSyncKHRRef(EGLDisplay egl_display, EGLSyncKHR egl_sync);
+  ~EGLSyncKHRRef();
+  EGLDisplay const egl_display;
+  EGLSyncKHR egl_sync;
+};
+
+typedef void* GLeglImageOES;

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

What I meant was: are you sure it's legit / standardized?  
If it is, it should be in a standards .h.  Add a TODO/file a crbug?

[sheu, 2013/01/11 10:41:42]

Done.

+typedef EGLBoolean (*MaliEglImageGetBufferExtPhandleFunc)(EGLImageKHR, EGLint*,
+                                                          void*);
+typedef EGLImageKHR (*EglCreateImageKhrFunc)(EGLDisplay, EGLContext, EGLenum,
+                                             EGLClientBuffer, const EGLint*);
+typedef EGLBoolean (*EglDestroyImageKhrFunc)(EGLDisplay, EGLImageKHR);
+typedef EGLSyncKHR (*EglCreateSyncKhrFunc)(EGLDisplay, EGLenum, const EGLint*);
+typedef EGLBoolean (*EglDestroySyncKhrFunc)(EGLDisplay, EGLSyncKHR);
+typedef EGLint (*EglClientWaitSyncKhrFunc)(EGLDisplay, EGLSyncKHR, EGLint,
+                                           EGLTimeKHR);
+typedef void (*GlEglImageTargetTexture2dOesFunc)(GLenum, GLeglImageOES);
+
+static void* libmali_handle = NULL;
+static MaliEglImageGetBufferExtPhandleFunc
+    mali_egl_image_get_buffer_ext_phandle = NULL;
+static EglCreateImageKhrFunc egl_create_image_khr = NULL;
+static EglDestroyImageKhrFunc egl_destroy_image_khr = NULL;
+static EglCreateSyncKhrFunc egl_create_sync_khr = NULL;
+static EglDestroySyncKhrFunc egl_destroy_sync_khr = NULL;
+static EglClientWaitSyncKhrFunc egl_client_wait_sync_khr = NULL;
+static GlEglImageTargetTexture2dOesFunc
+    gl_egl_image_target_texture_2d_oes = NULL;
+
+ExynosVideoDecodeAccelerator::BitstreamBufferRef::BitstreamBufferRef(
+    base::WeakPtr<Client>& client,
+    scoped_refptr<base::MessageLoopProxy>& client_message_loop_proxy,
+    base::SharedMemory* shm, size_t size, int32 input_id)
+    : client(client),
+      client_message_loop_proxy(client_message_loop_proxy),
+      shm(shm),
+      size(size),
+      bytes_used(0),
+      input_id(input_id) {
+}
+
+ExynosVideoDecodeAccelerator::BitstreamBufferRef::~BitstreamBufferRef() {
+  if (input_id >= 0)
+    client_message_loop_proxy->PostTask(FROM_HERE, base::Bind(
+        &Client::NotifyEndOfBitstreamBuffer, client, input_id));
+}
+
+ExynosVideoDecodeAccelerator::PictureBufferArrayRef::PictureBufferArrayRef(
+    EGLDisplay egl_display, EGLImageKHR egl_images[], int egl_image_fds[],
+    int32 client_ids[], int egl_images_count)
+    : egl_display(egl_display),
+      egl_images(egl_images),
+      egl_image_fds(egl_image_fds),
+      client_ids(client_ids),
+      egl_images_count(egl_images_count) {
+}
+
+ExynosVideoDecodeAccelerator::PictureBufferArrayRef::~PictureBufferArrayRef() {
+  DCHECK_EQ(egl_images != NULL, egl_image_fds != NULL);
+  if (egl_images == NULL)
+    return;
+
+  for (int i = 0; i < egl_images_count; ++i) {
+    if (egl_images[i] != EGL_NO_IMAGE_KHR)
+      egl_destroy_image_khr(egl_display, egl_images[i]);
+    if (egl_image_fds[i] != -1)
+      close(egl_image_fds[i]);
+  }
+}
+
+ExynosVideoDecodeAccelerator::EGLSyncKHRRef::EGLSyncKHRRef(
+    EGLDisplay egl_display, EGLSyncKHR egl_sync)
+    : egl_display(egl_display),
+      egl_sync(egl_sync) {
+}
+
+ExynosVideoDecodeAccelerator::EGLSyncKHRRef::~EGLSyncKHRRef() {
+  if (egl_sync != EGL_NO_SYNC_KHR)
+    egl_destroy_sync_khr(egl_display, egl_sync);
+}
+
+ExynosVideoDecodeAccelerator::MfcInputRecord::MfcInputRecord()
+    : at_device(false),
+      address(NULL),
+      length(0),
+      bytes_used(0),
+      input_id(-1) {
+}
+
+ExynosVideoDecodeAccelerator::MfcInputRecord::~MfcInputRecord() {
+}
+
+ExynosVideoDecodeAccelerator::MfcOutputRecord::MfcOutputRecord()
+    : at_device(false),
+      input_id(-1) {
+  bytes_used[0] = 0;
+  bytes_used[1] = 0;
+  address[0] = NULL;
+  address[1] = NULL;
+  length[0] = 0;
+  length[1] = 0;
+}
+
+ExynosVideoDecodeAccelerator::MfcOutputRecord::~MfcOutputRecord() {
+}
+
+ExynosVideoDecodeAccelerator::GscInputRecord::GscInputRecord()
+    : at_device(false),
+      mfc_output(-1) {
+}
+
+ExynosVideoDecodeAccelerator::GscInputRecord::~GscInputRecord() {
+}
+
+ExynosVideoDecodeAccelerator::GscOutputRecord::GscOutputRecord()
+    : at_device(false),
+      at_client(false),
+      fd(-1),
+      egl_image(EGL_NO_IMAGE_KHR),
+      egl_sync(EGL_NO_SYNC_KHR),
+      picture_id(-1) {
+}
+
+ExynosVideoDecodeAccelerator::GscOutputRecord::~GscOutputRecord() {
+}
+
+ExynosVideoDecodeAccelerator::ExynosVideoDecodeAccelerator(
+    EGLDisplay egl_display,
+    EGLContext egl_context,
+    Client* client,
+    const base::Callback<bool(void)>& make_context_current)
+    : child_message_loop_proxy_(base::MessageLoopProxy::current()),
+      weak_this_(base::AsWeakPtr(this)),
+      client_ptr_factory_(client),
+      client_(client_ptr_factory_.GetWeakPtr()),
+      decoder_thread_("ExynosDecoderThread"),
+      decoder_state_(kUninitialized),
+      decoder_current_bitstream_buffer_(NULL),
+      decoder_delay_bitstream_buffer_id_(-1),
+      decoder_current_input_buffer_(-1),
+      decoder_decode_buffer_tasks_scheduled_(0),
+      decoder_frames_at_client_(0),
+      decoder_flushing_(false),
+      mfc_fd_(-1),
+      mfc_input_streamon_(false),
+      mfc_input_buffer_count_(0),
+      mfc_input_buffer_queued_count_(0),
+      mfc_output_streamon_(false),
+      mfc_output_buffer_count_(0),
+      mfc_output_buffer_queued_count_(0),
+      mfc_output_buffer_pixelformat_(0),
+      gsc_fd_(-1),
+      gsc_input_streamon_(false),
+      gsc_input_buffer_count_(0),
+      gsc_input_buffer_queued_count_(0),
+      gsc_output_streamon_(false),
+      gsc_output_buffer_count_(0),
+      gsc_output_buffer_queued_count_(0),
+      device_poll_thread_("ExynosDevicePollThread"),
+      device_poll_interrupt_fd_(-1),
+      make_context_current_(make_context_current),
+      egl_display_(egl_display),
+      egl_context_(egl_context),
+      video_profile_(media::VIDEO_CODEC_PROFILE_UNKNOWN) {
+}
+
+ExynosVideoDecodeAccelerator::~ExynosVideoDecodeAccelerator() {
+  DCHECK(!decoder_thread_.message_loop());

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

s/message_loop/IsRunning/ here and in the next line

[sheu, 2013/01/11 10:41:42]

Done.

+  DCHECK(!device_poll_thread_.message_loop());
+  // Nuke the entire site from orbit -- it's the only way to be sure.
+  if (device_poll_interrupt_fd_ != -1) {
+    close(device_poll_interrupt_fd_);
+    device_poll_interrupt_fd_ = -1;
+  }
+  if (gsc_fd_ != -1) {
+    DestroyGscInputBuffers();
+    DestroyGscOutputBuffers();
+    close(gsc_fd_);
+    gsc_fd_ = -1;
+  }
+  if (mfc_fd_ != -1) {
+    DestroyMfcInputBuffers();
+    DestroyMfcOutputBuffers();
+    close(mfc_fd_);
+    mfc_fd_ = -1;
+  }
+
+  // These maps have members that should be manually destroyed, e.g. file
+  // descriptors, mmap() segments, etc.
+  DCHECK(mfc_input_buffer_map_.empty());
+  DCHECK(mfc_output_buffer_map_.empty());
+  DCHECK(gsc_input_buffer_map_.empty());
+  DCHECK(gsc_output_buffer_map_.empty());
+}
+
+bool ExynosVideoDecodeAccelerator::Initialize(
+    media::VideoCodecProfile profile) {
+  DVLOG(3) << "Initialize()";
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+  DCHECK_EQ(decoder_state_, kUninitialized);
+
+  switch (profile) {
+    case media::H264PROFILE_BASELINE:
+      DVLOG(2) << "Initialize(): profile H264PROFILE_BASELINE";
+      break;
+    case media::H264PROFILE_MAIN:
+      DVLOG(2) << "Initialize(): profile H264PROFILE_MAIN";
+      break;
+    case media::H264PROFILE_HIGH:
+      DVLOG(2) << "Initialize(): profile H264PROFILE_HIGH";
+      break;
+    case media::VP8PROFILE_MAIN:
+      DVLOG(2) << "Initialize(): profile VP8PROFILE_MAIN";
+      break;
+    default:
+      DLOG(ERROR) << "Initialize(): unsupported profile=" << profile;
+      return false;
+  };
+  video_profile_ = profile;
+
+  static bool sandbox_initialized = PostSandboxInitialization();
+  if (!sandbox_initialized) {
+    DLOG(ERROR) << "Initialize(): PostSandboxInitialization() failed";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+
+  if (egl_display_ == EGL_NO_DISPLAY) {
+    DLOG(ERROR) << "Initialize(): could not get EGLDisplay";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+
+  if (egl_context_ == EGL_NO_CONTEXT) {
+    DLOG(ERROR) << "Initialize(): could not get EGLContext";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+
+  // Open the video devices.
+  DVLOG(2) << "Initialize(): opening MFC device: " << EXYNOS_MFC_DEVICE;
+  mfc_fd_ = open(EXYNOS_MFC_DEVICE, O_RDWR | O_NONBLOCK | O_CLOEXEC);
+  if (mfc_fd_ == -1) {
+    DPLOG(ERROR) << "Initialize(): could not open MFC device: "
+                 << EXYNOS_MFC_DEVICE;
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+  DVLOG(2) << "Initialize(): opening GSC device: " << EXYNOS_GSC_DEVICE;
+  gsc_fd_ = open(EXYNOS_GSC_DEVICE, O_RDWR | O_NONBLOCK | O_CLOEXEC);
+  if (gsc_fd_ == -1) {
+    DPLOG(ERROR) << "Initialize(): could not open GSC device: "
+                 << EXYNOS_GSC_DEVICE;
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+
+  // Create the interrupt fd.
+  DCHECK_EQ(device_poll_interrupt_fd_, -1);
+  device_poll_interrupt_fd_ = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+  if (device_poll_interrupt_fd_ == -1) {
+    DPLOG(ERROR) << "Initialize(): eventfd() failed";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+
+  // Capabilities check.
+  struct v4l2_capability caps;
+  const __u32 kCapsRequired =
+      V4L2_CAP_VIDEO_CAPTURE_MPLANE |
+      V4L2_CAP_VIDEO_OUTPUT_MPLANE |
+      V4L2_CAP_STREAMING;
+  IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_QUERYCAP, &caps);
+  if ((caps.capabilities & kCapsRequired) != kCapsRequired) {
+    DLOG(ERROR) << "Initialize(): ioctl() failed: VIDIOC_QUERYCAP"
+        ", caps check failed: 0x" << std::hex << caps.capabilities;
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_QUERYCAP, &caps);
+  if ((caps.capabilities & kCapsRequired) != kCapsRequired) {
+    DLOG(ERROR) << "Initialize(): ioctl() failed: VIDIOC_QUERYCAP"
+        ", caps check failed: 0x" << std::hex << caps.capabilities;
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+
+  // Some random ioctls that Exynos requires.
+  struct v4l2_control control;
+  memset(&control, 0, sizeof(control));
+  control.id = V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY; // also VP8
+  control.value = 8; // Magic number from Samsung folks.
+  IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_S_CTRL, &control);
+
+  if (!make_context_current_.Run()) {
+    DLOG(ERROR) << "Initialize(): could not make context current";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+
+  if (!CreateMfcInputBuffers())
+    return false;
+
+  // MFC output format has to be setup before streaming starts.
+  struct v4l2_format format;
+  memset(&format, 0, sizeof(format));
+  format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  format.fmt.pix_mp.pixelformat = V4L2_PIX_FMT_NV12MT_16X16;
+  IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_S_FMT, &format);
+
+  // Initialize format-specific bits.
+  if (video_profile_ >= media::H264PROFILE_MIN &&
+      video_profile_ <= media::H264PROFILE_MAX) {
+    decoder_h264_parser_.reset(new content::H264Parser());
+  }
+
+  if (!decoder_thread_.Start()) {
+    DLOG(ERROR) << "Initialize(): decoder thread failed to start";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+
+  SetDecoderState(kInitialized);
+
+  child_message_loop_proxy_->PostTask(FROM_HERE, base::Bind(
+      &Client::NotifyInitializeDone, client_));
+  return true;
+}
+
+void ExynosVideoDecodeAccelerator::Decode(
+    const media::BitstreamBuffer& bitstream_buffer) {
+  DVLOG(1) << "Decode(): input_id=" << bitstream_buffer.id()
+           << ", size=" << bitstream_buffer.size();
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+
+  scoped_ptr<BitstreamBufferRef> bitstream_record(new BitstreamBufferRef(
+      client_, child_message_loop_proxy_,
+      new base::SharedMemory(bitstream_buffer.handle(), true),
+      bitstream_buffer.size(), bitstream_buffer.id()));
+  if (!bitstream_record->shm->Map(bitstream_buffer.size())) {
+    DLOG(ERROR) << "Decode(): could not map bitstream_buffer";
+    NOTIFY_ERROR(UNREADABLE_INPUT);
+    return;
+  }
+  DVLOG(3) << "Decode(): mapped to addr=" << bitstream_record->shm->memory();
+
+  // DecodeTask() will take care of running a DecodeBufferTask().
+  decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+      &ExynosVideoDecodeAccelerator::DecodeTask, base::Unretained(this),
+      base::Passed(&bitstream_record)));
+}
+
+void ExynosVideoDecodeAccelerator::AssignPictureBuffers(
+    const std::vector<media::PictureBuffer>& buffers) {
+  DVLOG(3) << "AssignPictureBuffers(): buffer_count=" << buffers.size();
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+
+  if (static_cast<int>(buffers.size()) != gsc_output_buffer_count_) {
+    DLOG(ERROR) << "AssignPictureBuffers(): invalid buffer_count";
+    NOTIFY_ERROR(INVALID_ARGUMENT);
+    return;
+  }
+
+  if (!make_context_current_.Run()) {
+    DLOG(ERROR) << "AssignPictureBuffers(): could not make context current";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return;
+  }
+
+  scoped_ptr<PictureBufferArrayRef> pic_buffers_ref(
+      new PictureBufferArrayRef(
+          egl_display_, new EGLImageKHR[buffers.size()],
+          new int[buffers.size()], new int32[buffers.size()], buffers.size()));
+  for (int i = 0; i < pic_buffers_ref->egl_images_count; ++i) {
+    pic_buffers_ref->egl_images[i] = EGL_NO_IMAGE_KHR;
+    pic_buffers_ref->egl_image_fds[i] = -1;
+    pic_buffers_ref->client_ids[i] = -1;
+  }
+
+  const static EGLint kImageAttrs[] = {
+    EGL_IMAGE_PRESERVED_KHR, 0,
+    EGL_NONE,
+  };
+  Display* x_display = base::MessagePumpForUI::GetDefaultXDisplay();
+  glActiveTexture(GL_TEXTURE0);
+  for (int i = 0; i < pic_buffers_ref->egl_images_count; ++i) {
+    // Create the X pixmap and then create an EGLImageKHR from it, so we can
+    // get dma_buf backing.
+    Pixmap pixmap = XCreatePixmap(x_display, RootWindow(x_display, 0),
+        buffers[i].size().width(), buffers[i].size().height(), 32);
+    if (!pixmap) {
+      DLOG(ERROR) << "AssignPictureBuffers(): could not create X pixmap";
+      NOTIFY_ERROR(PLATFORM_FAILURE);
+      return;
+    }
+    glBindTexture(GL_TEXTURE_2D, buffers[i].texture_id());
+    EGLImageKHR egl_image;
+    egl_image = egl_create_image_khr(
+        egl_display_, EGL_NO_CONTEXT, EGL_NATIVE_PIXMAP_KHR,
+        (EGLClientBuffer)pixmap, kImageAttrs);
+    // We can free the X pixmap immediately -- according to the
+    // EGL_KHR_image_base spec, the backing storage does not go away until the
+    // last referencing EGLImage is destroyed.
+    XFreePixmap(x_display, pixmap);
+    if (egl_image == EGL_NO_IMAGE_KHR) {
+      DLOG(ERROR) << "AssignPictureBuffers(): could not create EGLImageKHR";
+      NOTIFY_ERROR(PLATFORM_FAILURE);
+      return;
+    }
+    pic_buffers_ref->egl_images[i] = egl_image;
+    int fd;
+    if (!mali_egl_image_get_buffer_ext_phandle(
+        pic_buffers_ref->egl_images[i], NULL, &fd)) {
+      DLOG(ERROR) << "AssignPictureBuffers(): "
+                  << "could not get EGLImageKHR dmabuf fd";
+      NOTIFY_ERROR(PLATFORM_FAILURE);
+      return;
+    }
+    pic_buffers_ref->egl_image_fds[i] = fd;
+    gl_egl_image_target_texture_2d_oes(GL_TEXTURE_2D, egl_image);
+    pic_buffers_ref->client_ids[i] = buffers[i].id();
+  }
+  decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+      &ExynosVideoDecodeAccelerator::AssignPictureBuffersTask,
+      base::Unretained(this), base::Passed(&pic_buffers_ref)));
+}
+
+void ExynosVideoDecodeAccelerator::ReusePictureBuffer(int32 picture_buffer_id) {
+  DVLOG(3) << "ReusePictureBuffer(): picture_buffer_id=" << picture_buffer_id;
+  // Must be run on child thread, as we'll insert a sync in the EGL context.
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+
+  if (!make_context_current_.Run()) {
+    DLOG(ERROR) << "ReusePictureBuffer(): could not make context current";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return;
+  }
+
+  EGLSyncKHR egl_sync;
+  egl_sync = egl_create_sync_khr(egl_display_, EGL_SYNC_FENCE_KHR, NULL);
+  if (egl_sync == EGL_NO_SYNC_KHR) {
+    DLOG(ERROR) << "ReusePictureBuffer(): eglCreateSyncKHR() failed";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return;
+  }
+
+  scoped_ptr<EGLSyncKHRRef> egl_sync_ref(new EGLSyncKHRRef(
+      egl_display_, egl_sync));
+  decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+      &ExynosVideoDecodeAccelerator::ReusePictureBufferTask,
+      base::Unretained(this), picture_buffer_id, base::Passed(&egl_sync_ref)));
+}
+
+void ExynosVideoDecodeAccelerator::Flush() {
+  DVLOG(3) << "Flush()";
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+  decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+      &ExynosVideoDecodeAccelerator::FlushTask, base::Unretained(this)));
+}
+
+void ExynosVideoDecodeAccelerator::Reset() {
+  DVLOG(3) << "Reset()";
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+  decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+      &ExynosVideoDecodeAccelerator::ResetTask, base::Unretained(this)));
+}
+
+void ExynosVideoDecodeAccelerator::Destroy() {
+  DVLOG(3) << "Destroy()";
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+
+  // We're destroying; cancel all callbacks.
+  client_ptr_factory_.InvalidateWeakPtrs();
+
+  // If the decoder thread is running, destroy using posted task.
+  if (decoder_thread_.IsRunning()) {
+    decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+        &ExynosVideoDecodeAccelerator::DestroyTask, base::Unretained(this)));
+    // DestroyTask() will cause the decoder_thread_ to flush all tasks.
+    decoder_thread_.Stop();
+  } else {
+    // Otherwise, call the destroy task directly.
+    DestroyTask();
+  }
+
+  // Set to kError state just in case.
+  SetDecoderState(kError);
+
+  delete this;
+}
+
+// static
+void ExynosVideoDecodeAccelerator::PreSandboxInitialization() {
+  DVLOG(3) << "PreSandboxInitialization()";
+  dlerror();
+
+  libmali_handle = dlopen(EXYNOS_MALI_DRIVER, RTLD_LAZY | RTLD_LOCAL);
+  if (libmali_handle == NULL) {
+    DPLOG(ERROR) << "failed to dlopen() " << EXYNOS_MALI_DRIVER
+                 << ": " << dlerror();
+  }
+}
+
+// static
+bool ExynosVideoDecodeAccelerator::PostSandboxInitialization() {
+  DVLOG(3) << "PostSandboxInitialization()";
+  if (libmali_handle == NULL) {
+    DLOG(ERROR) << "PostSandboxInitialization(): no " << EXYNOS_MALI_DRIVER
+                << " driver handle";
+    return false;
+  }
+
+  dlerror();
+
+  POSTSANDBOX_DLSYM(libmali_handle,
+                    mali_egl_image_get_buffer_ext_phandle,
+                    MaliEglImageGetBufferExtPhandleFunc,
+                    "mali_egl_image_get_buffer_ext_phandle");
+
+  POSTSANDBOX_DLSYM(libmali_handle,
+                    egl_create_image_khr,
+                    EglCreateImageKhrFunc,
+                    "eglCreateImageKHR");
+
+  POSTSANDBOX_DLSYM(libmali_handle,
+                    egl_destroy_image_khr,
+                    EglDestroyImageKhrFunc,
+                    "eglDestroyImageKHR");
+
+  POSTSANDBOX_DLSYM(libmali_handle,
+                    egl_create_sync_khr,
+                    EglCreateSyncKhrFunc,
+                    "eglCreateSyncKHR");
+
+  POSTSANDBOX_DLSYM(libmali_handle,
+                    egl_destroy_sync_khr,
+                    EglDestroySyncKhrFunc,
+                    "eglDestroySyncKHR");
+
+  POSTSANDBOX_DLSYM(libmali_handle,
+                    egl_client_wait_sync_khr,
+                    EglClientWaitSyncKhrFunc,
+                    "eglClientWaitSyncKHR");
+
+  POSTSANDBOX_DLSYM(libmali_handle,
+                    gl_egl_image_target_texture_2d_oes,
+                    GlEglImageTargetTexture2dOesFunc,
+                    "glEGLImageTargetTexture2DOES");
+
+  return true;
+}
+
+void ExynosVideoDecodeAccelerator::DecodeTask(
+    scoped_ptr<BitstreamBufferRef> bitstream_record) {
+  DVLOG(3) << "DecodeTask(): input_id=" << bitstream_record->input_id;
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  TRACE_EVENT1("Video Decoder", "EVDA::DecodeTask", "input_id",
+               bitstream_record->input_id);
+
+  if (decoder_state_ == kResetting || decoder_flushing_) {
+    // In the case that we're resetting or flushing, we need to delay decoding
+    // the BitstreamBuffers that come after the Reset() or Flush() call.  When
+    // we're here, we know that this DecodeTask() was scheduled by a Decode()
+    // call that came after (in the client thread) the Reset() or Flush() call;
+    // thus set up the delay if necessary.
+    if (decoder_delay_bitstream_buffer_id_ == -1)
+      decoder_delay_bitstream_buffer_id_ = bitstream_record->input_id;
+  } else if (decoder_state_ == kError) {
+    DVLOG(2) << "DecodeTask(): early out: kError state";
+    return;
+  }
+
+  decoder_input_queue_.push_back(
+      linked_ptr<BitstreamBufferRef>(bitstream_record.release()));
+  decoder_decode_buffer_tasks_scheduled_++;
+  DecodeBufferTask();
+}
+
+void ExynosVideoDecodeAccelerator::DecodeBufferTask() {
+  DVLOG(3) << "DecodeBufferTask()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  TRACE_EVENT0("Video Decoder", "EVDA::DecodeBufferTask");
+
+  decoder_decode_buffer_tasks_scheduled_--;
+
+  if (decoder_state_ == kResetting) {
+    DVLOG(2) << "DecodeBufferTask(): early out: kResetting state";
+    return;
+  } else if (decoder_state_ == kError) {
+    DVLOG(2) << "DecodeBufferTask(): early out: kError state";
+    return;
+  }
+
+  if (decoder_current_bitstream_buffer_ == NULL) {
+    if (decoder_input_queue_.empty()) {
+      // We're waiting for a new buffer -- exit without scheduling a new task.
+      return;
+    }
+    linked_ptr<BitstreamBufferRef>& buffer_ref = decoder_input_queue_.front();
+    if (decoder_delay_bitstream_buffer_id_ == buffer_ref->input_id) {
+      // We're asked to delay decoding on this and subsequent buffers.
+      return;
+    }
+
+    // Setup to use the next buffer.
+    decoder_current_bitstream_buffer_.reset(buffer_ref.release());
+    decoder_input_queue_.pop_front();
+    DVLOG(3) << "DecodeBufferTask(): reading input_id="
+             << decoder_current_bitstream_buffer_->input_id
+             << ", addr=" << decoder_current_bitstream_buffer_->shm->memory()
+             << ", size=" << decoder_current_bitstream_buffer_->size;
+  }
+  bool schedule_task = false;
+  const size_t size = decoder_current_bitstream_buffer_->size;
+  size_t decoded_size;
+  if (size == 0) {
+    const int32 input_id = decoder_current_bitstream_buffer_->input_id;
+    decoded_size = 0;
+    if (input_id >= 0) {
+      // This is a buffer queued from the client that has zero size.  Skip.
+      schedule_task = true;
+    } else {
+      // This is a buffer of zero size, queued to flush the pipe.  Flush.
+      DCHECK_EQ(decoder_current_bitstream_buffer_->shm.get(),
+                static_cast<base::SharedMemory*>(NULL));
+      // Enqueue a buffer guaranteed to be empty.  To do that, we flush the
+      // current input, enqueue no data to the next flame, then flush that down.

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

typo: flame

[sheu, 2013/01/11 10:41:42]

Done.

+      if (!FlushInputFrame() || !AppendToInputFrame(NULL, 0) ||
+          !FlushInputFrame()) {
+        // If we failed to enqueue the empty buffer (due to pipeline
+        // backpressure), don't advance the bitstream buffer queue, and don't
+        // schedule the next task.  This bitstream buffer queue entry will get
+        // reprocessed when the pipeline frees up.

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

So it's ok that if the first FIF() and ATIF() return true, but the last FIF()
returns false, then the next run through this codepath will call all of
FIF/ATIF/FIF again?

(ends up with two flushing frames in the pipeline)

[sheu, 2013/01/11 10:41:42]

We'll just end up with two flushing frame in the pipe.  This should not be a
problem.

There is a rather unlikely condition where we manage to keep trying to queue a
flush faster than the hardware can process completely empty buffers, which might
livelock.  Rather far-fetched (I think), but well, better to be safe.

Done.

+        schedule_task = false;
+      } else {
+        DVLOG(2) << "DecodeBufferTask(): enqueued flush buffer";
+        schedule_task = true;
+      }
+    }
+  } else {
+    // This is a buffer queued from the client, with actual contents.  Decode.
+    const void* const data =
+        reinterpret_cast<const uint8*>(
+            decoder_current_bitstream_buffer_->shm->memory()) +
+        decoder_current_bitstream_buffer_->bytes_used;
+    const size_t data_size =
+        decoder_current_bitstream_buffer_->size -
+        decoder_current_bitstream_buffer_->bytes_used;
+    if (!FindFrameFragment(reinterpret_cast<const uint8*>(data), data_size,
+                           &decoded_size))
+      return;

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

Should this notify error?
E.g. if the bitstream is invalid or unsupported, what's the desired/actual
behavior?

[sheu, 2013/01/11 10:41:42]

I suppose we can error here, instead of trying to continue.

+    switch (decoder_state_) {
+      case kInitialized:
+      case kAfterReset:
+        schedule_task = DecodeBufferInitial(data, decoded_size, &decoded_size);
+        break;
+      case kDecoding:
+        schedule_task = DecodeBufferContinue(data, decoded_size, &decoded_size);
+        break;
+      default:
+        NOTIFY_ERROR(ILLEGAL_STATE);
+        return;
+    }
+  }
+  if (decoder_state_ == kError) {
+    // Failed during decode.
+    return;
+  }
+
+  if (schedule_task) {
+    decoder_current_bitstream_buffer_->bytes_used += decoded_size;
+    if (decoder_current_bitstream_buffer_->bytes_used ==
+        decoder_current_bitstream_buffer_->size) {
+      // Our current bitstream buffer is done; return it.
+      int32 input_id = decoder_current_bitstream_buffer_->input_id;
+      DVLOG(3) << "DecodeBufferTask(): finished input_id=" << input_id;
+      // BitstreamBufferRef destructor calls NotifyEndOfBitstreamBuffer().
+      decoder_current_bitstream_buffer_.reset();
+    }
+    ScheduleDecodeBufferTaskIfNeeded();
+  }
+}
+
+bool ExynosVideoDecodeAccelerator::FindFrameFragment(
+    const uint8* data,
+    size_t size,
+    size_t* endpos) {
+  if (video_profile_ >= media::H264PROFILE_MIN &&
+      video_profile_ <= media::H264PROFILE_MAX) {
+    // For H264, we need to feed HW one frame at a time.  This is going to take
+    // some parsing of our input stream.
+    decoder_h264_parser_->SetStream(data, size);
+    content::H264NALU nalu;
+    content::H264Parser::Result result;
+
+    // Find the first NAL.
+    result = decoder_h264_parser_->AdvanceToNextNALU(&nalu);
+    if (result == content::H264Parser::kInvalidStream ||
+        result == content::H264Parser::kUnsupportedStream)
+      return false;
+    *endpos = (nalu.data + nalu.size) - data;
+    if (result == content::H264Parser::kEOStream)
+      return true;
+
+    // Keep on peeking the next NALs while they don't indicate a frame
+    // boundary.
+    for (;;) {
+      result = decoder_h264_parser_->AdvanceToNextNALU(&nalu);
+      if (result == content::H264Parser::kInvalidStream ||
+          result == content::H264Parser::kUnsupportedStream)
+        return false;
+      if (result == content::H264Parser::kEOStream)
+        return true;
+      switch (nalu.nal_unit_type) {
+        case content::H264NALU::kNonIDRSlice:
+        case content::H264NALU::kIDRSlice:
+          // For these two, if the "first_mb_in_slice" field is zero, start a
+          // new frame and return.  This field is Exp-Golomb coded starting on
+          // the eighth data bit of the NAL; a zero value is encoded with a
+          // leading '1' bit in the byte, which we can detect as the byte being
+          // (unsigned) greater than or equal to 0x80.
+          if (nalu.data[1] >= 0x80)
+            return true;
+          break;
+        case content::H264NALU::kSPS:
+        case content::H264NALU::kPPS:
+        case content::H264NALU::kEOSeq:
+        case content::H264NALU::kEOStream:
+          // These unconditionally signal a frame boundary.
+          return true;
+        default:
+          // For all others, keep going.
+          break;
+      }
+      *endpos = (nalu.data + nalu.size) - reinterpret_cast<const uint8*>(data);
+    }
+    NOTREACHED();
+    return false;
+  } else {
+    DCHECK_GE(video_profile_, media::VP8PROFILE_MIN);
+    DCHECK_LE(video_profile_, media::VP8PROFILE_MAX);
+    // For VP8, we can just dump the entire buffer.  No fragmentation needed.
+    *endpos = size;
+    return true;
+  }
+}
+
+void ExynosVideoDecodeAccelerator::ScheduleDecodeBufferTaskIfNeeded() {
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+
+  // If we're behind on tasks, schedule another one.
+  int buffers_to_decode = decoder_input_queue_.size();
+  if (decoder_current_bitstream_buffer_ != NULL)
+    buffers_to_decode++;
+  if (decoder_decode_buffer_tasks_scheduled_ < buffers_to_decode) {
+    decoder_decode_buffer_tasks_scheduled_++;
+    decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+        &ExynosVideoDecodeAccelerator::DecodeBufferTask,
+        base::Unretained(this)));
+  }
+}
+
+bool ExynosVideoDecodeAccelerator::DecodeBufferInitial(
+    const void* data, size_t size, size_t* endpos) {
+  DVLOG(3) << "DecodeBufferInitial(): data=" << data << ", size=" << size;
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  DCHECK_NE(decoder_state_, kDecoding);
+  DCHECK(!device_poll_thread_.IsRunning());
+  // Initial decode.  We haven't been able to get output stream format info yet.
+  // Get it, and start decoding.
+
+  // Copy in and send to HW.
+  if (!AppendToInputFrame(data, size) || !FlushInputFrame())
+    return false;
+
+  // Recycle buffers.
+  DequeueMfc();
+
+  // Check and see if we have format info yet.
+  struct v4l2_format format;
+  format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  if (ioctl(mfc_fd_, VIDIOC_G_FMT, &format) != 0) {
+    if (errno == EINVAL) {
+      // We will get EINVAL if we haven't seen sufficient stream to decode the
+      // format.  Return true and schedule the next buffer.
+      *endpos = size;
+      return true;
+    } else {
+      DPLOG(ERROR) << "DecodeBufferInitial(): ioctl() failed: VIDIOC_G_FMT";
+      NOTIFY_ERROR(PLATFORM_FAILURE);
+      return false;
+    }
+  }
+
+  // Run this initialization only on first startup.
+  if (decoder_state_ == kInitialized) {
+    DVLOG(3) << "DecodeBufferInitial(): running one-time initialization";
+    // Success! Setup our parameters.
+    CHECK_EQ(format.fmt.pix_mp.num_planes, 2);
+    frame_buffer_size_.SetSize(
+        format.fmt.pix_mp.width, format.fmt.pix_mp.height);
+    mfc_output_buffer_size_[0] = format.fmt.pix_mp.plane_fmt[0].sizeimage;
+    mfc_output_buffer_size_[1] = format.fmt.pix_mp.plane_fmt[1].sizeimage;
+    mfc_output_buffer_pixelformat_ = format.fmt.pix_mp.pixelformat;
+    DCHECK_EQ(mfc_output_buffer_pixelformat_, V4L2_PIX_FMT_NV12MT_16X16);
+
+    // Create our other buffers.
+    if (!CreateMfcOutputBuffers() || !CreateGscInputBuffers() ||
+        !CreateGscOutputBuffers())
+      return false;
+
+    // MFC expects to process the initial buffer once during stream init to
+    // configure stream parameters, but will not consume the steam data on that
+    // iteration.  Subsequent iterations (including after reset) do not require
+    // the stream init step.
+    *endpos = 0;
+  } else {
+    *endpos = size;
+  }
+
+  // StartDevicePoll will raise the error if there is one.
+  if (!StartDevicePoll())
+    return false;
+
+  decoder_state_ = kDecoding;
+  ScheduleDecodeBufferTaskIfNeeded();
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::DecodeBufferContinue(
+    const void* data, size_t size, size_t* endpos) {
+  DVLOG(3) << "DecodeBufferContinue(): data=" << data << ", size=" << size;
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_EQ(decoder_state_, kDecoding);
+
+  // We've already setup our output stream parameters, so just keep on truckin'.
+  *endpos = size;

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

Symmetry is nice and all, but this is just a pure head-scratcher.  I'd drop the
out param entirely.

[sheu, 2013/01/11 10:41:42]

Fine :-P

+  // Both of these calls will set kError state if they fail.
+  return (AppendToInputFrame(data, size) && FlushInputFrame());
+}
+
+bool ExynosVideoDecodeAccelerator::AppendToInputFrame(
+    const void* data, size_t size) {
+  DVLOG(3) << "AppendToInputFrame()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  DCHECK_NE(decoder_state_, kResetting);
+  DCHECK_NE(decoder_state_, kError);
+  // This routine can handle data == NULL and size == 0, which occurs when
+  // we queue an empty buffer for the purposes of flushing the pipe.
+
+  // Flush if we're too big
+  if (decoder_current_input_buffer_ != -1) {
+    MfcInputRecord& input_record =
+        mfc_input_buffer_map_[decoder_current_input_buffer_];
+    if (input_record.bytes_used + size > input_record.length) {
+      if (!FlushInputFrame())
+        return false;
+      decoder_current_input_buffer_ = -1;
+    }
+  }
+
+  // Try to get an available input buffer
+  if (decoder_current_input_buffer_ == -1) {
+    if (mfc_free_input_buffers_.empty()) {
+      // See if we can get more free buffers from HW
+      DequeueMfc();
+      if (mfc_free_input_buffers_.empty()) {
+        // Nope!
+        DVLOG(2) << "AppendToInputFrame(): stalled for input buffers";
+        return false;
+      }
+    }
+    decoder_current_input_buffer_ = mfc_free_input_buffers_.back();
+    mfc_free_input_buffers_.pop_back();
+    MfcInputRecord& input_record =
+        mfc_input_buffer_map_[decoder_current_input_buffer_];
+    DCHECK_EQ(input_record.bytes_used, 0);
+    DCHECK_EQ(input_record.input_id, -1);
+    DCHECK(decoder_current_bitstream_buffer_ != NULL);
+    input_record.input_id = decoder_current_bitstream_buffer_->input_id;
+  }
+
+  DCHECK_EQ(data == NULL, size == 0);
+  if (size == 0) {
+    // If we asked for an empty buffer, return now.  We return only after
+    // getting the next input buffer, since we might actually want an empty
+    // input buffer for flushing purposes.
+    return true;
+  }
+
+  // Copy in to the buffer.
+  MfcInputRecord& input_record =
+      mfc_input_buffer_map_[decoder_current_input_buffer_];
+  if (size > input_record.length - input_record.bytes_used) {
+    LOG(ERROR) << "AppendToInputFrame(): over-size frame, erroring";
+    NOTIFY_ERROR(UNREADABLE_INPUT);
+    return false;
+  }
+  memcpy((char*)input_record.address + input_record.bytes_used, data, size);
+  input_record.bytes_used += size;
+
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::FlushInputFrame() {
+  DVLOG(3) << "FlushInputFrame()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  DCHECK_NE(decoder_state_, kResetting);
+  DCHECK_NE(decoder_state_, kError);
+
+  if (decoder_current_input_buffer_ == -1)
+    return true;
+
+  MfcInputRecord& input_record =
+      mfc_input_buffer_map_[decoder_current_input_buffer_];
+  // If input_id >= 0, this input buffer was promped by a bitstream buffer we

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

typo: promped

[sheu, 2013/01/11 10:41:42]

Done.

+  // got from the client.  We can skip it if it is empty.

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

I don't understand this comment and the following line (esp. given I thought I
understood PS#18's version of this code at l.971-973).  Can you clarify?

[sheu, 2013/01/11 10:41:42]

I reworded and reversed the order of the condition because I thought it would
make things less confusing.  It looks like that didn't help :-(

The logic is still the same.  Adding comment.

+  if (input_record.input_id >= 0 && input_record.bytes_used == 0) {
+    input_record.input_id = -1;
+    mfc_free_input_buffers_.push_back(decoder_current_input_buffer_);
+    decoder_current_input_buffer_ = -1;
+    return true;
+  }
+
+  // Queue it to MFC.
+  mfc_input_ready_queue_.push_back(decoder_current_input_buffer_);
+  decoder_current_input_buffer_ = -1;
+  DVLOG(3) << "FlushInputFrame(): submitting input_id="
+           << input_record.input_id;
+  // Kick the MFC once since there's new available input for it.
+  EnqueueMfc();
+
+  return (decoder_state_ != kError);
+}
+
+void ExynosVideoDecodeAccelerator::AssignPictureBuffersTask(
+    scoped_ptr<PictureBufferArrayRef> pic_buffers) {
+  DVLOG(3) << "AssignPictureBuffersTask()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  TRACE_EVENT0("Video Decoder", "EVDA::AssignPictureBuffersTask");
+
+  // We run AssignPictureBuffersTask even if we're in kResetting.
+  if (decoder_state_ == kError) {
+    DVLOG(2) << "AssignPictureBuffersTask(): early out: kError state";
+    return;
+  }
+
+  DCHECK_EQ(pic_buffers->egl_images_count,
+            static_cast<int>(gsc_output_buffer_map_.size()));
+  for (size_t i = 0; i < gsc_output_buffer_map_.size(); ++i) {
+    // We should be blank right now.
+    GscOutputRecord& output_record = gsc_output_buffer_map_[i];
+    DCHECK_EQ(output_record.fd, -1);
+    DCHECK_EQ(output_record.egl_image, EGL_NO_IMAGE_KHR);
+    DCHECK_EQ(output_record.egl_sync, EGL_NO_SYNC_KHR);
+    DCHECK_EQ(output_record.picture_id, -1);
+    output_record.fd = pic_buffers->egl_image_fds[i];
+    output_record.egl_image = pic_buffers->egl_images[i];
+    output_record.picture_id = pic_buffers->client_ids[i];
+
+    // Take ownership of the EGLImage and fd.
+    pic_buffers->egl_images[i] = EGL_NO_IMAGE_KHR;
+    pic_buffers->egl_image_fds[i] = -1;
+    // And add this buffer to the free list.
+    gsc_free_output_buffers_.push_back(i);
+  }
+
+  // We got buffers!  Kick the GSC.
+  EnqueueGsc();
+}
+
+void ExynosVideoDecodeAccelerator::ServiceDeviceTask() {
+  DVLOG(3) << "ServiceDeviceTask()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  DCHECK_NE(decoder_state_, kInitialized);
+  DCHECK_NE(decoder_state_, kAfterReset);
+  TRACE_EVENT0("Video Decoder", "EVDA::ServiceDeviceTask");
+
+  if (decoder_state_ == kResetting) {
+    DVLOG(2) << "ServiceDeviceTask(): early out: kResetting state";
+    return;
+  } else if (decoder_state_ == kError) {
+    DVLOG(2) << "ServiceDeviceTask(): early out: kError state";
+    return;
+  }
+
+  DequeueMfc();
+  DequeueGsc();
+  EnqueueMfc();
+  EnqueueGsc();
+
+  // Clear the interrupt fd.
+  if (!ClearDevicePollInterrupt())
+    return;
+
+  unsigned int poll_fds = 0;
+  // Add MFC fd, if we should poll on it.
+  // MFC can be polled as soon as either input or output buffers are queued.
+  if (mfc_input_buffer_queued_count_ + mfc_output_buffer_queued_count_ > 0)
+    poll_fds |= kPollMfc;
+  // Add GSC fd, if we should poll on it.
+  // GSC has to wait until both input and output buffers are queued.
+  if (gsc_input_buffer_queued_count_ > 0 && gsc_output_buffer_queued_count_ > 0)
+    poll_fds |= kPollGsc;
+
+  // ServiceDeviceTask() should only ever be scheduled from DevicePollTask(),
+  // so either:
+  // * device_poll_thread_ is running normally
+  // * device_poll_thread_ scheduled us, but then a ResetTask() or DestroyTask()
+  //   shut it down, in which case we're either in kResetting or kError states
+  //   respectively, and we should have early-outed already.
+  DCHECK(device_poll_thread_.message_loop());
+  // Queue the DevicePollTask() now.
+  device_poll_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+      &ExynosVideoDecodeAccelerator::DevicePollTask,
+      base::Unretained(this),
+      poll_fds));
+
+  DVLOG(1) << "ServiceDeviceTask(): buffer counts: DEC["
+           << decoder_input_queue_.size() << "->"
+           << mfc_input_ready_queue_.size() << "] => MFC["
+           << mfc_free_input_buffers_.size() << "+"
+           << mfc_input_buffer_queued_count_ << "/"
+           << mfc_input_buffer_count_ << "->"
+           << mfc_free_output_buffers_.size() << "+"
+           << mfc_output_buffer_queued_count_ << "/"
+           << mfc_output_buffer_count_ << "] => "
+           << mfc_output_gsc_input_queue_.size() << " => GSC["
+           << gsc_free_input_buffers_.size() << "+"
+           << gsc_input_buffer_queued_count_ << "/"
+           << gsc_input_buffer_count_ << "->"
+           << gsc_free_output_buffers_.size() << "+"
+           << gsc_output_buffer_queued_count_ << "/"
+           << gsc_output_buffer_count_ << "] => VDA["
+           << decoder_frames_at_client_ << "]";
+
+  ScheduleDecodeBufferTaskIfNeeded();
+}
+
+void ExynosVideoDecodeAccelerator::EnqueueMfc() {
+  DVLOG(3) << "EnqueueMfc()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  TRACE_EVENT0("Video Decoder", "EVDA::EnqueueMfc");
+
+  // Drain the pipe of completed decode buffers.
+  const int old_mfc_inputs_queued = mfc_input_buffer_queued_count_;
+  while (!mfc_input_ready_queue_.empty()) {
+    if (!EnqueueMfcInputRecord())
+      return;
+  }
+  if (old_mfc_inputs_queued == 0 && mfc_input_buffer_queued_count_ != 0) {
+    // We just started up a previously empty queue.
+    // Queue state changed; signal interrupt.
+    if (!SetDevicePollInterrupt())
+      return;
+    // Start VIDIOC_STREAMON if we haven't yet.
+    if (!mfc_input_streamon_) {
+      __u32 type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+      IOCTL_OR_ERROR_RETURN(mfc_fd_, VIDIOC_STREAMON, &type);
+      mfc_input_streamon_ = true;
+    }
+  }
+
+  // Enqueue all the MFC outputs we can.
+  const int old_mfc_outputs_queued = mfc_output_buffer_queued_count_;
+  while (!mfc_free_output_buffers_.empty()) {
+    if (!EnqueueMfcOutputRecord())
+      return;
+  }
+  if (old_mfc_outputs_queued == 0 && mfc_output_buffer_queued_count_ != 0) {
+    // We just started up a previously empty queue.
+    // Queue state changed; signal interrupt.
+    if (!SetDevicePollInterrupt())
+      return;
+    // Start VIDIOC_STREAMON if we haven't yet.
+    if (!mfc_output_streamon_) {
+      __u32 type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+      IOCTL_OR_ERROR_RETURN(mfc_fd_, VIDIOC_STREAMON, &type);
+      mfc_output_streamon_ = true;
+    }
+  }
+}
+
+void ExynosVideoDecodeAccelerator::DequeueMfc() {
+  DVLOG(3) << "DequeueMfc()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  TRACE_EVENT0("Video Decoder", "EVDA::DequeueMfc");
+
+  // Dequeue completed MFC input (VIDEO_OUTPUT) buffers, and recycle to the free
+  // list.
+  struct v4l2_buffer dqbuf;
+  struct v4l2_plane planes[2];
+  while (mfc_input_buffer_queued_count_ > 0) {
+    DCHECK(mfc_input_streamon_);
+    memset(&dqbuf, 0, sizeof(dqbuf));
+    dqbuf.type   = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+    dqbuf.memory = V4L2_MEMORY_MMAP;
+    if (ioctl(mfc_fd_, VIDIOC_DQBUF, &dqbuf) != 0) {
+      if (errno == EAGAIN) {
+        // EAGAIN if we're just out of buffers to dequeue.
+        break;
+      }
+      DPLOG(ERROR) << "DequeueMfc(): ioctl() failed: VIDIOC_DQBUF";
+      NOTIFY_ERROR(PLATFORM_FAILURE);
+      return;
+    }
+    MfcInputRecord& input_record = mfc_input_buffer_map_[dqbuf.index];
+    DCHECK(input_record.at_device);
+    mfc_free_input_buffers_.push_back(dqbuf.index);
+    input_record.at_device = false;
+    input_record.bytes_used = 0;
+    input_record.input_id = -1;
+    mfc_input_buffer_queued_count_--;
+  }
+
+  // Dequeue completed MFC output (VIDEO_CAPTURE) buffers, and queue to the
+  // completed queue.
+  while (mfc_output_buffer_queued_count_ > 0) {
+    DCHECK(mfc_output_streamon_);
+    memset(&dqbuf, 0, sizeof(dqbuf));
+    memset(planes, 0, sizeof(planes));
+    dqbuf.type   = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+    dqbuf.memory = V4L2_MEMORY_MMAP;
+    dqbuf.m.planes = planes;
+    dqbuf.length = 2;
+    if (ioctl(mfc_fd_, VIDIOC_DQBUF, &dqbuf) != 0) {
+      if (errno == EAGAIN) {
+        // EAGAIN if we're just out of buffers to dequeue.
+        break;
+      }
+      DPLOG(ERROR) << "DequeueMfc(): ioctl() failed: VIDIOC_DQBUF";
+      NOTIFY_ERROR(PLATFORM_FAILURE);
+      return;
+    }
+    MfcOutputRecord& output_record = mfc_output_buffer_map_[dqbuf.index];
+    DCHECK(output_record.at_device);
+    if (dqbuf.m.planes[0].bytesused + dqbuf.m.planes[1].bytesused == 0) {
+      // This is an empty output buffer returned as part of a flush.
+      mfc_free_output_buffers_.push_back(dqbuf.index);
+      output_record.at_device = false;
+      output_record.input_id = -1;
+      output_record.bytes_used[0] = 0;
+      output_record.bytes_used[1] = 0;
+    } else {
+      // This is an output buffer with contents to pass down the pipe.
+      const long int input_id = dqbuf.timestamp.tv_sec;
+      DCHECK(input_id >= 0);
+      mfc_output_gsc_input_queue_.push_back(dqbuf.index);
+      output_record.at_device = false;
+      output_record.input_id = input_id;
+      output_record.bytes_used[0] = dqbuf.m.planes[0].bytesused;
+      output_record.bytes_used[1] = dqbuf.m.planes[1].bytesused;

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

I think you missed this comment:
AFAICT l.1207-1210 can be moved outside the if/else and the corresponding 4
lines in  the "then" clause can be dropped (greatly clarifying the difference
between the flush and non-flush cases, which is whether the output_record is
added to gsc_input or mfc_free).

[sheu, 2013/01/11 10:41:42]

Sounds good.

+      DVLOG(3) << "DequeueMfc(): dequeued input_id=" << input_id;
+      // We don't count this output buffer dequeued yet, or add it to the free
+      // list, as it has data GSC needs to process.
+
+      // We have new frames in mfc_output_gsc_input_queue_.  Kick the pipe.
+      SetDevicePollInterrupt();
+    }
+    mfc_output_buffer_queued_count_--;
+  }
+
+  NotifyFlushDoneIfNeeded();
+}
+
+void ExynosVideoDecodeAccelerator::EnqueueGsc() {
+  DVLOG(3) << "EnqueueGsc()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  DCHECK_NE(decoder_state_, kInitialized);
+  TRACE_EVENT0("Video Decoder", "EVDA::EnqueueGsc");
+
+  // Drain the pipe of completed MFC output buffers.
+  const int old_gsc_inputs_queued = gsc_input_buffer_queued_count_;
+  while (!mfc_output_gsc_input_queue_.empty()) {
+    if (gsc_free_input_buffers_.empty())

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

I think you missed the comment:
while (foo()) {
  if (!bar())
    break;
  ...
}

is equivalent to the shorter (and, IMO, clearer):

while (foo() && bar()) {
  ...
}

[sheu, 2013/01/11 10:41:42]

Done.

+      break;
+    if (!EnqueueGscInputRecord())
+      return;
+  }
+  if (old_gsc_inputs_queued == 0 && gsc_input_buffer_queued_count_ != 0) {
+    // We just started up a previously empty queue.
+    // Queue state changed; signal interrupt.
+    if (!SetDevicePollInterrupt())
+      return;
+    // Start VIDIOC_STREAMON if we haven't yet.
+    if (!gsc_input_streamon_) {
+      __u32 type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+      IOCTL_OR_ERROR_RETURN(gsc_fd_, VIDIOC_STREAMON, &type);
+      gsc_input_streamon_ = true;
+    }
+  }
+
+  // Enqueue a GSC output, only if we need one
+  if (gsc_input_buffer_queued_count_ != 0 &&
+      gsc_output_buffer_queued_count_ == 0 &&
+      !gsc_free_output_buffers_.empty()) {
+    const int old_gsc_outputs_queued = gsc_output_buffer_queued_count_;
+    if (!EnqueueGscOutputRecord())
+      return;
+    if (old_gsc_outputs_queued == 0 && gsc_output_buffer_queued_count_ != 0) {
+      // We just started up a previously empty queue.
+      // Queue state changed; signal interrupt.
+      if (!SetDevicePollInterrupt())
+        return;
+      // Start VIDIOC_STREAMON if we haven't yet.
+      if (!gsc_output_streamon_) {
+        __u32 type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+        IOCTL_OR_ERROR_RETURN(gsc_fd_, VIDIOC_STREAMON, &type);
+        gsc_output_streamon_ = true;
+      }
+    }
+  }
+  // Bug check: GSC is liable to race conditions if more than one buffer is
+  // simultaneously queued.
+  DCHECK_GE(1, gsc_output_buffer_queued_count_);
+}
+
+void ExynosVideoDecodeAccelerator::DequeueGsc() {
+  DVLOG(3) << "DequeueGsc()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK_NE(decoder_state_, kUninitialized);
+  DCHECK_NE(decoder_state_, kInitialized);
+  DCHECK_NE(decoder_state_, kAfterReset);
+  TRACE_EVENT0("Video Decoder", "EVDA::DequeueGsc");
+
+  // Dequeue completed GSC input (VIDEO_OUTPUT) buffers, and recycle to the free
+  // list.  Also recycle the corresponding MFC output buffers at this time.
+  struct v4l2_buffer dqbuf;
+  while (gsc_input_buffer_queued_count_ > 0) {
+    DCHECK(gsc_input_streamon_);
+    memset(&dqbuf, 0, sizeof(dqbuf));
+    dqbuf.type   = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+    dqbuf.memory = V4L2_MEMORY_DMABUF;
+    if (ioctl(gsc_fd_, VIDIOC_DQBUF, &dqbuf) != 0) {
+      if (errno == EAGAIN) {
+        // EAGAIN if we're just out of buffers to dequeue.
+        break;
+      }
+      DPLOG(ERROR) << "DequeueGsc(): ioctl() failed: VIDIOC_DQBUF";
+      NOTIFY_ERROR(PLATFORM_FAILURE);
+      return;
+    }
+    GscInputRecord& input_record = gsc_input_buffer_map_[dqbuf.index];
+    MfcOutputRecord& output_record =
+        mfc_output_buffer_map_[input_record.mfc_output];
+    DCHECK(input_record.at_device);
+    gsc_free_input_buffers_.push_back(dqbuf.index);
+    mfc_free_output_buffers_.push_back(input_record.mfc_output);
+    input_record.at_device = false;
+    input_record.mfc_output = -1;
+    output_record.input_id = -1;
+    gsc_input_buffer_queued_count_--;
+  }
+
+  // Dequeue completed GSC output (VIDEO_CAPTURE) buffers, and send them off to
+  // the client.  Don't recycle to its free list yet -- we can't do that until
+  // ReusePictureBuffer() returns it to us.
+  while (gsc_output_buffer_queued_count_ > 0) {
+    DCHECK(gsc_output_streamon_);
+    memset(&dqbuf, 0, sizeof(dqbuf));
+    dqbuf.type   = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+    dqbuf.memory = V4L2_MEMORY_DMABUF;
+    if (ioctl(gsc_fd_, VIDIOC_DQBUF, &dqbuf) != 0) {
+      if (errno == EAGAIN) {
+        // EAGAIN if we're just out of buffers to dequeue.
+        break;
+      }
+      DPLOG(ERROR) << "DequeueGsc(): ioctl() failed: VIDIOC_DQBUF";
+      NOTIFY_ERROR(PLATFORM_FAILURE);
+      return;
+    }
+    GscOutputRecord& output_record = gsc_output_buffer_map_[dqbuf.index];
+    DCHECK(output_record.at_device);
+    DCHECK(!output_record.at_client);
+    DCHECK_EQ(output_record.egl_sync, EGL_NO_SYNC_KHR);
+    output_record.at_device = false;
+    output_record.at_client = true;
+    gsc_output_buffer_queued_count_--;
+    child_message_loop_proxy_->PostTask(FROM_HERE, base::Bind(
+        &Client::PictureReady, client_, media::Picture(
+            output_record.picture_id, dqbuf.timestamp.tv_sec)));
+    decoder_frames_at_client_++;
+  }
+
+  NotifyFlushDoneIfNeeded();
+}
+
+void ExynosVideoDecodeAccelerator::NotifyFlushDoneIfNeeded() {
+  if (!decoder_flushing_)
+    return;
+
+  // Pipeline is empty when:
+  // * There is no currently filling input buffer.
+  // * MFC input holding queue is empty.
+  // * All MFC input (VIDEO_OUTPUT) buffers are returned.
+  // * MFC -> GSC holding queue is empty.
+  // * All GSC input (VIDEO_OUTPUT) buffers are returned.
+  if (decoder_current_input_buffer_ != -1)
+    return;
+  if ((mfc_input_ready_queue_.size() +
+      mfc_input_buffer_queued_count_ + mfc_output_gsc_input_queue_.size() +
+      gsc_input_buffer_queued_count_ + gsc_output_buffer_queued_count_ ) != 0)
+    return;
+
+  decoder_delay_bitstream_buffer_id_ = -1;
+  decoder_flushing_ = false;
+  child_message_loop_proxy_->PostTask(FROM_HERE, base::Bind(
+    &Client::NotifyFlushDone, client_));
+
+  // While we were flushing, we early-outed DecodeBufferTask()s.
+  ScheduleDecodeBufferTaskIfNeeded();
+}
+
+bool ExynosVideoDecodeAccelerator::EnqueueMfcInputRecord() {
+  DVLOG(3) << "EnqueueMfcInputRecord()";
+  DCHECK(!mfc_input_ready_queue_.empty());
+
+  // Enqueue a MFC input (VIDEO_OUTPUT) buffer.
+  const int buffer = mfc_input_ready_queue_.back();
+  MfcInputRecord& input_record = mfc_input_buffer_map_[buffer];
+  DCHECK(!input_record.at_device);
+  struct v4l2_buffer qbuf;
+  struct v4l2_plane qbuf_plane;
+  memset(&qbuf, 0, sizeof(qbuf));
+  memset(&qbuf_plane, 0, sizeof(qbuf_plane));
+  qbuf.index                 = buffer;
+  qbuf.type                  = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+  qbuf.timestamp.tv_sec      = input_record.input_id;
+  qbuf.memory                = V4L2_MEMORY_MMAP;
+  qbuf.m.planes              = &qbuf_plane;
+  qbuf.m.planes[0].bytesused = input_record.bytes_used;
+  qbuf.length                = 1;
+  IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_QBUF, &qbuf);
+  mfc_input_ready_queue_.pop_back();
+  input_record.at_device = true;
+  mfc_input_buffer_queued_count_++;
+  DVLOG(3) << "EnqueueMfcInputRecord(): enqueued input_id="
+           << input_record.input_id;
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::EnqueueMfcOutputRecord() {
+  DVLOG(3) << "EnqueueMfcOutputRecord()";
+  DCHECK(!mfc_free_output_buffers_.empty());
+
+  // Enqueue a MFC output (VIDEO_CAPTURE) buffer.
+  const int buffer = mfc_free_output_buffers_.back();
+  MfcOutputRecord& output_record = mfc_output_buffer_map_[buffer];
+  DCHECK(!output_record.at_device);
+  DCHECK_EQ(output_record.input_id, -1);
+  struct v4l2_buffer qbuf;
+  struct v4l2_plane qbuf_planes[2];
+  memset(&qbuf, 0, sizeof(qbuf));
+  memset(qbuf_planes, 0, sizeof(qbuf_planes));
+  qbuf.index    = buffer;
+  qbuf.type     = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  qbuf.memory   = V4L2_MEMORY_MMAP;
+  qbuf.m.planes = qbuf_planes;
+  qbuf.length   = 2;
+  IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_QBUF, &qbuf);
+  mfc_free_output_buffers_.pop_back();
+  output_record.at_device = true;
+  mfc_output_buffer_queued_count_++;
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::EnqueueGscInputRecord() {
+  DVLOG(3) << "EnqueueGscInputRecord()";
+  DCHECK(!gsc_free_input_buffers_.empty());
+
+  // Enqueue a GSC input (VIDEO_OUTPUT) buffer for a complete MFC output
+  // (VIDEO_CAPTURE) buffer.
+  const int mfc_buffer = mfc_output_gsc_input_queue_.front();
+  const int gsc_buffer = gsc_free_input_buffers_.back();
+  MfcOutputRecord& output_record = mfc_output_buffer_map_[mfc_buffer];
+  DCHECK(!output_record.at_device);
+  GscInputRecord& input_record = gsc_input_buffer_map_[gsc_buffer];
+  DCHECK(!input_record.at_device);
+  DCHECK_EQ(input_record.mfc_output, -1);
+  struct v4l2_buffer qbuf;
+  struct v4l2_plane qbuf_planes[2];
+  memset(&qbuf, 0, sizeof(qbuf));
+  memset(qbuf_planes, 0, sizeof(qbuf_planes));
+  qbuf.index                 = gsc_buffer;
+  qbuf.type                  = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+  qbuf.timestamp.tv_sec      = output_record.input_id;
+  qbuf.memory                = V4L2_MEMORY_USERPTR;
+  qbuf.m.planes              = qbuf_planes;
+  qbuf.m.planes[0].bytesused = output_record.bytes_used[0];
+  qbuf.m.planes[0].length    = mfc_output_buffer_size_[0];
+  qbuf.m.planes[0].m.userptr = (unsigned long)output_record.address[0];
+  qbuf.m.planes[1].bytesused = output_record.bytes_used[1];
+  qbuf.m.planes[1].length    = mfc_output_buffer_size_[1];
+  qbuf.m.planes[1].m.userptr = (unsigned long)output_record.address[1];
+  qbuf.length                = 2;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_QBUF, &qbuf);
+  mfc_output_gsc_input_queue_.pop_front();
+  gsc_free_input_buffers_.pop_back();
+  input_record.at_device = true;
+  input_record.mfc_output = mfc_buffer;
+  output_record.bytes_used[0] = 0;
+  output_record.bytes_used[1] = 0;
+  gsc_input_buffer_queued_count_++;
+  DVLOG(3) << "EnqueueGscInputRecord(): enqueued input_id="
+           << output_record.input_id;
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::EnqueueGscOutputRecord() {
+  DVLOG(3) << "EnqueueGscOutputRecord()";
+  DCHECK(!gsc_free_output_buffers_.empty());
+
+  // Enqueue a GSC output (VIDEO_CAPTURE) buffer.
+  const int buffer = gsc_free_output_buffers_.front();
+  GscOutputRecord& output_record = gsc_output_buffer_map_[buffer];
+  DCHECK(!output_record.at_device);
+  DCHECK(!output_record.at_client);
+  if (output_record.egl_sync != EGL_NO_SYNC_KHR) {
+    TRACE_EVENT0(
+        "Video Decoder",
+        "EVDA::EnqueueGscOutputRecord: eglClientWaitSyncKHR");
+    // If we have to wait for completion, wait.  Note that
+    // gsc_free_output_buffers_ is a FIFO queue, so we always wait on the
+    // buffer that has been in the queue the longest.
+    egl_client_wait_sync_khr(egl_display_, output_record.egl_sync, 0,
+        EGL_FOREVER_KHR);
+    egl_destroy_sync_khr(egl_display_, output_record.egl_sync);
+    output_record.egl_sync = EGL_NO_SYNC_KHR;
+  }
+  struct v4l2_buffer qbuf;
+  struct v4l2_plane qbuf_plane;
+  memset(&qbuf, 0, sizeof(qbuf));
+  memset(&qbuf_plane, 0, sizeof(qbuf_plane));
+  qbuf.index            = buffer;
+  qbuf.type             = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  qbuf.memory           = V4L2_MEMORY_DMABUF;
+  qbuf.m.planes         = &qbuf_plane;
+  qbuf.m.planes[0].m.fd = output_record.fd;
+  qbuf.length           = 1;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_QBUF, &qbuf);
+  gsc_free_output_buffers_.pop_front();
+  output_record.at_device = true;
+  gsc_output_buffer_queued_count_++;
+  return true;
+}
+
+void ExynosVideoDecodeAccelerator::ReusePictureBufferTask(
+    int32 picture_buffer_id, scoped_ptr<EGLSyncKHRRef> egl_sync_ref) {
+  DVLOG(3) << "ReusePictureBufferTask(): picture_buffer_id="
+           << picture_buffer_id;
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  TRACE_EVENT0("Video Decoder", "EVDA::ReusePictureBufferTask");
+
+  // We run ReusePictureBufferTask even if we're in kResetting.
+  if (decoder_state_ == kError) {
+    DVLOG(2) << "ReusePictureBufferTask(): early out: kError state";
+    return;
+  }
+
+  size_t index;
+  for (index = 0; index < gsc_output_buffer_map_.size(); ++index)
+    if (gsc_output_buffer_map_[index].picture_id == picture_buffer_id)
+      break;
+
+  if (index >= gsc_output_buffer_map_.size()) {
+    DLOG(ERROR) << "ReusePictureBufferTask(): picture_buffer_id not found";
+    NOTIFY_ERROR(INVALID_ARGUMENT);
+    return;
+  }
+
+  GscOutputRecord& output_record = gsc_output_buffer_map_[index];
+  if (output_record.at_device || !output_record.at_client) {
+    DLOG(ERROR) << "ReusePictureBufferTask(): picture_buffer_id not reusable";
+    NOTIFY_ERROR(INVALID_ARGUMENT);
+    return;
+  }
+
+  DCHECK_EQ(output_record.egl_sync, EGL_NO_SYNC_KHR);
+  output_record.at_client = false;
+  output_record.egl_sync = egl_sync_ref->egl_sync;
+  gsc_free_output_buffers_.push_back(index);
+  decoder_frames_at_client_--;
+  // Take ownership of the EGLSync.
+  egl_sync_ref->egl_sync = EGL_NO_SYNC_KHR;
+  // We got a buffer back, so kick the GSC.
+  EnqueueGsc();
+}
+
+void ExynosVideoDecodeAccelerator::FlushTask() {
+  DVLOG(3) << "FlushTask()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  TRACE_EVENT0("Video Decoder", "EVDA::FlushTask");
+
+  // Flush outstanding buffers.
+  if (decoder_state_ == kResetting || decoder_state_ == kInitialized ||
+      decoder_state_ == kAfterReset) {
+    // Nothing in the pipe; return done immediately.

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

In kResetting how do you know there's "nothing in the pipe"?
Is there any reason to do this special-casing short-circuit?

[sheu, 2013/01/11 10:41:42]

If we're resetting, ResetTask() has already wiped the pipeline, so we can
early-out.  Evidently this calls for a comment.

Done.

+    child_message_loop_proxy_->PostTask(FROM_HERE, base::Bind(
+      &Client::NotifyFlushDone, client_));
+    return;
+  } else if (decoder_state_ == kError) {
+    DVLOG(2) << "FlushTask(): early out: kError state";
+    return;
+  }
+
+  // We don't support stacked flushing.
+  DCHECK(!decoder_flushing_);
+
+  // Queue up an empty buffer -- this triggers the flush.
+  decoder_input_queue_.push_back(linked_ptr<BitstreamBufferRef>(
+      new BitstreamBufferRef(client_, child_message_loop_proxy_, NULL, 0,
+                             kFlushBufferId)));
+  decoder_flushing_ = true;
+
+  ScheduleDecodeBufferTaskIfNeeded();
+}
+
+void ExynosVideoDecodeAccelerator::ResetTask() {
+  DVLOG(3) << "ResetTask()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  TRACE_EVENT0("Video Decoder", "EVDA::ResetTask");
+
+  if (decoder_state_ == kError) {
+    DVLOG(2) << "ResetTask(): early out: kError state";
+    return;
+  }
+
+  // We stop streaming, but we _don't_ destroy our buffers.
+  if (!StopDevicePoll())
+    return;
+
+  decoder_current_bitstream_buffer_.reset();
+  decoder_input_queue_.clear();
+
+  decoder_current_input_buffer_ = -1;
+  decoder_decode_buffer_tasks_scheduled_ = 0;
+
+  // If we were flushing, we'll never return any more BitstreamBuffers or
+  // PictureBuffers; they have all been dropped and returned by now.
+  NotifyFlushDoneIfNeeded();
+
+  // Mark that we're resetting, then enqueue a ResetDoneTask().  All intervening
+  // jobs will early-out in the kResetting state.
+  decoder_state_ = kResetting;
+  decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+      &ExynosVideoDecodeAccelerator::ResetDoneTask, base::Unretained(this)));
+}
+
+void ExynosVideoDecodeAccelerator::ResetDoneTask() {
+  DVLOG(3) << "ResetDoneTask()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  TRACE_EVENT0("Video Decoder", "EVDA::ResetDoneTask");
+
+  if (decoder_state_ == kError) {
+    DVLOG(2) << "ResetDoneTask(): early out: kError state";
+    return;
+  }
+
+  // Reset format-specific bits.
+  if (video_profile_ >= media::H264PROFILE_MIN &&
+      video_profile_ <= media::H264PROFILE_MAX) {
+    decoder_h264_parser_.reset(new content::H264Parser());
+  }
+
+  // Jobs drained, we're finished resetting.
+  DCHECK_EQ(decoder_state_, kResetting);
+  decoder_state_ = kAfterReset;
+  decoder_delay_bitstream_buffer_id_ = -1;
+  child_message_loop_proxy_->PostTask(FROM_HERE, base::Bind(
+      &Client::NotifyResetDone, client_));
+
+  // While we were resetting, we early-outed DecodeBufferTask()s.
+  ScheduleDecodeBufferTaskIfNeeded();
+}
+
+void ExynosVideoDecodeAccelerator::DestroyTask() {
+  DVLOG(3) << "DestroyTask()";
+  TRACE_EVENT0("Video Decoder", "EVDA::DestroyTask");
+
+  // DestroyTask() should run regardless of decoder_state_.
+
+  // Stop streaming and the device_poll_thread_.
+  StopDevicePoll();
+
+  decoder_current_bitstream_buffer_.reset();
+  decoder_current_input_buffer_ = -1;
+  decoder_decode_buffer_tasks_scheduled_ = 0;
+  decoder_frames_at_client_ = 0;
+  decoder_input_queue_.clear();
+  decoder_flushing_ = false;
+
+  // Set our state to kError.  Just in case.
+  decoder_state_ = kError;
+}
+
+bool ExynosVideoDecodeAccelerator::StartDevicePoll() {
+  DVLOG(3) << "StartDevicePoll()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+  DCHECK(!device_poll_thread_.IsRunning());
+
+  // Start up the device poll thread and schedule its first DevicePollTask().
+  if (!device_poll_thread_.Start()) {
+    DLOG(ERROR) << "StartDevicePoll(): Device thread failed to start";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+  device_poll_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+      &ExynosVideoDecodeAccelerator::DevicePollTask,
+      base::Unretained(this),
+      0));
+
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::StopDevicePoll() {
+  DVLOG(3) << "StopDevicePoll()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+
+  // Signal the DevicePollTask() to stop, and stop the device poll thread.
+  if (!SetDevicePollInterrupt())
+    return false;
+  device_poll_thread_.Stop();
+  // Clear the interrupt now, to be sure.
+  if (!ClearDevicePollInterrupt())
+    return false;
+
+  // Stop streaming.
+  if (mfc_input_streamon_) {
+    __u32 type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+    IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_STREAMOFF, &type);
+  }
+  mfc_input_streamon_ = false;
+  if (mfc_output_streamon_) {
+    __u32 type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+    IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_STREAMOFF, &type);
+  }
+  mfc_output_streamon_ = false;
+  if (gsc_input_streamon_) {
+    __u32 type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+    IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_STREAMOFF, &type);
+  }
+  gsc_input_streamon_ = false;
+  if (gsc_output_streamon_) {
+    __u32 type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+    IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_STREAMOFF, &type);
+  }
+  gsc_output_streamon_ = false;
+
+  // Reset all our accounting info.
+  mfc_input_ready_queue_.clear();
+  mfc_free_input_buffers_.clear();
+  DCHECK_EQ(mfc_input_buffer_count_,
+      static_cast<int>(mfc_input_buffer_map_.size()));
+  for (size_t i = 0; i < mfc_input_buffer_map_.size(); ++i) {
+    mfc_free_input_buffers_.push_back(i);
+    mfc_input_buffer_map_[i].at_device = false;
+    mfc_input_buffer_map_[i].bytes_used = 0;
+    mfc_input_buffer_map_[i].input_id = -1;
+  }
+  mfc_input_buffer_queued_count_ = 0;
+  mfc_free_output_buffers_.clear();
+  DCHECK_EQ(mfc_output_buffer_count_,
+     static_cast<int>(mfc_output_buffer_map_.size()));
+  for (size_t i = 0; i < mfc_output_buffer_map_.size(); ++i) {
+    mfc_free_output_buffers_.push_back(i);
+    mfc_output_buffer_map_[i].at_device = false;
+    mfc_output_buffer_map_[i].input_id = -1;
+  }
+  mfc_output_buffer_queued_count_ = 0;
+  mfc_output_gsc_input_queue_.clear();
+  gsc_free_input_buffers_.clear();
+  DCHECK_EQ(gsc_input_buffer_count_,
+      static_cast<int>(gsc_input_buffer_map_.size()));
+  for (size_t i = 0; i < gsc_input_buffer_map_.size(); ++i) {
+    gsc_free_input_buffers_.push_back(i);
+    gsc_input_buffer_map_[i].at_device = false;
+    gsc_input_buffer_map_[i].mfc_output = -1;
+  }
+  gsc_input_buffer_queued_count_ = 0;
+  gsc_free_output_buffers_.clear();
+  DCHECK_EQ(gsc_output_buffer_count_,
+      static_cast<int>(gsc_output_buffer_map_.size()));
+  for (size_t i = 0; i < gsc_output_buffer_map_.size(); ++i) {
+    // Only mark those free that aren't being held by the VDA.
+    if (!gsc_output_buffer_map_[i].at_client) {
+      gsc_free_output_buffers_.push_back(i);
+      gsc_output_buffer_map_[i].at_device = false;
+    }
+  }
+  gsc_output_buffer_queued_count_ = 0;
+
+  DVLOG(3) << "StopDevicePoll(): device poll stopped";
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::SetDevicePollInterrupt() {
+  DVLOG(3) << "SetDevicePollInterrupt()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+
+  ssize_t ret;
+  const uint64 buf = 1;
+  ret = write(device_poll_interrupt_fd_, &buf, sizeof(buf));
+  if (ret == -1) {
+    DPLOG(ERROR) << "SetDevicePollInterrupt(): write() failed";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return false;
+  }
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::ClearDevicePollInterrupt() {
+  DVLOG(3) << "ClearDevicePollInterrupt()";
+  DCHECK_EQ(decoder_thread_.message_loop(), MessageLoop::current());
+
+  int ret;
+  uint64 buf;
+  ret = read(device_poll_interrupt_fd_, &buf, sizeof(buf));

[Ami GONE FROM CHROMIUM, 2013/01/11 00:46:33]

buf is "used" before ret (param is eval'd pre-dispatch, which happens before
assignment).  Either way, this contravenes chrome style guidelines.

[sheu, 2013/01/11 10:41:42]

Alrighty then, fixed here and above.

+  if (ret == -1) {
+    if (errno == EAGAIN) {
+      // No interrupt flag set, and we're reading nonblocking.  Not an error.
+      return true;
+    } else {
+      DPLOG(ERROR) << "ClearDevicePollInterrupt(): read() failed";
+      NOTIFY_ERROR(PLATFORM_FAILURE);
+      return false;
+    }
+  }
+  return true;
+}
+
+void ExynosVideoDecodeAccelerator::DevicePollTask(unsigned int poll_fds) {
+  DVLOG(3) << "DevicePollTask()";
+  DCHECK_EQ(device_poll_thread_.message_loop(), MessageLoop::current());
+  TRACE_EVENT0("Video Decoder", "EVDA::DevicePollTask");
+
+  // This routine just polls the set of device fds, and schedules a
+  // ServiceDeviceTask() on decoder_thread_ when processing needs to occur.
+  // Other threads may notify this task to return early by writing to
+  // device_poll_interrupt_fd_.
+  struct pollfd pollfds[3];
+  nfds_t nfds;
+
+  // Add device_poll_interrupt_fd_;
+  pollfds[0].fd = device_poll_interrupt_fd_;
+  pollfds[0].events = POLLIN | POLLERR;
+  nfds = 1;
+
+  if (poll_fds & kPollMfc) {
+    DVLOG(3) << "DevicePollTask(): adding MFC to poll() set";
+    pollfds[nfds].fd = mfc_fd_;
+    pollfds[nfds].events = POLLIN | POLLOUT | POLLERR;
+    nfds++;
+  }
+  // Add GSC fd, if we should poll on it.
+  // GSC has to wait until both input and output buffers are queued.
+  if (poll_fds & kPollGsc) {
+    DVLOG(3) << "DevicePollTask(): adding GSC to poll() set";
+    pollfds[nfds].fd = gsc_fd_;
+    pollfds[nfds].events = POLLIN | POLLOUT | POLLERR;
+    nfds++;
+  }
+
+  // Poll it!
+  int ret;
+  do {
+    ret = poll(pollfds, nfds, -1);
+  } while (ret < 1 && errno == EINTR);
+  if (ret == -1) {
+    DPLOG(ERROR) << "DevicePollTask(): poll() failed";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return;
+  }
+
+  // All processing should happen on ServiceDeviceTask(), since we shouldn't
+  // touch decoder state from this thread.
+  decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+      &ExynosVideoDecodeAccelerator::ServiceDeviceTask,
+      base::Unretained(this)));
+}
+
+void ExynosVideoDecodeAccelerator::NotifyError(Error error) {
+  DVLOG(2) << "NotifyError()";
+
+  if (!child_message_loop_proxy_->BelongsToCurrentThread()) {
+    child_message_loop_proxy_->PostTask(FROM_HERE, base::Bind(
+        &ExynosVideoDecodeAccelerator::NotifyError, weak_this_, error));
+    return;
+  }
+
+  if (client_) {
+    client_->NotifyError(error);
+    client_ptr_factory_.InvalidateWeakPtrs();
+  }
+}
+
+void ExynosVideoDecodeAccelerator::SetDecoderState(State state) {
+  DVLOG(3) << "SetDecoderState(): state=%d" << state;
+
+  // We can touch decoder_state_ only if this is the decoder thread or the
+  // decoder thread isn't running.
+  if (decoder_thread_.message_loop() != NULL &&
+      decoder_thread_.message_loop() != MessageLoop::current()) {
+    decoder_thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
+        &ExynosVideoDecodeAccelerator::SetDecoderState,
+        base::Unretained(this), state));
+  } else {
+    decoder_state_ = state;
+  }
+}
+
+bool ExynosVideoDecodeAccelerator::CreateMfcInputBuffers() {
+  DVLOG(3) << "CreateMfcInputBuffers()";
+  // We always run this as we prepare to initialize.
+  DCHECK_EQ(decoder_state_, kUninitialized);
+  DCHECK(!mfc_input_streamon_);
+  DCHECK_EQ(mfc_input_buffer_count_, 0);
+
+  __u32 pixelformat = 0;
+  if (video_profile_ >= media::H264PROFILE_MIN &&
+      video_profile_ <= media::H264PROFILE_MAX) {
+    pixelformat = V4L2_PIX_FMT_H264;
+  } else if (video_profile_ >= media::VP8PROFILE_MIN &&
+             video_profile_ <= media::VP8PROFILE_MAX) {
+    pixelformat = V4L2_PIX_FMT_VP8;
+  } else {
+    NOTREACHED();
+  }
+
+  struct v4l2_format format;
+  memset(&format, 0, sizeof(format));
+  format.type                              = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+  format.fmt.pix_mp.pixelformat            = pixelformat;
+  format.fmt.pix_mp.plane_fmt[0].sizeimage = kMfcInputBufferMaxSize;
+  format.fmt.pix_mp.num_planes             = 1;
+  IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_S_FMT, &format);
+
+  struct v4l2_requestbuffers reqbufs;
+  memset(&reqbufs, 0, sizeof(reqbufs));
+  reqbufs.count  = kMfcInputBufferCount;
+  reqbufs.type   = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+  reqbufs.memory = V4L2_MEMORY_MMAP;
+  IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_REQBUFS, &reqbufs);
+  mfc_input_buffer_count_ = reqbufs.count;
+  mfc_input_buffer_map_.resize(mfc_input_buffer_count_);
+  for (int i = 0; i < mfc_input_buffer_count_; ++i) {
+    mfc_free_input_buffers_.push_back(i);
+
+    // Query for the MEMORY_MMAP pointer.
+    struct v4l2_plane planes[1];
+    struct v4l2_buffer buffer;
+    memset(&buffer, 0, sizeof(buffer));
+    memset(planes, 0, sizeof(planes));
+    buffer.index    = i;
+    buffer.type     = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+    buffer.memory   = V4L2_MEMORY_MMAP;
+    buffer.m.planes = planes;
+    buffer.length   = 1;
+    IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_QUERYBUF, &buffer);
+    void* address = mmap(NULL, buffer.m.planes[0].length,
+        PROT_READ | PROT_WRITE, MAP_SHARED, mfc_fd_,
+        buffer.m.planes[0].m.mem_offset);
+    if (address == MAP_FAILED) {
+      DPLOG(ERROR) << "CreateMfcInputBuffers(): mmap() failed";
+      return false;
+    }
+    mfc_input_buffer_map_[i].address = address;
+    mfc_input_buffer_map_[i].length = buffer.m.planes[0].length;
+  }
+
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::CreateMfcOutputBuffers() {
+  DVLOG(3) << "CreateMfcOutputBuffers()";
+  DCHECK_EQ(decoder_state_, kInitialized);
+  DCHECK(!mfc_output_streamon_);
+  DCHECK_EQ(mfc_output_buffer_count_, 0);
+
+  // Number of MFC output buffers we need.
+  struct v4l2_control ctrl;
+  memset(&ctrl, 0, sizeof(ctrl));
+  ctrl.id = V4L2_CID_MIN_BUFFERS_FOR_CAPTURE;
+  IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_G_CTRL, &ctrl);
+
+  // Output format setup in Initialize().
+
+  // Allocate the output buffers.
+  struct v4l2_requestbuffers reqbufs;
+  memset(&reqbufs, 0, sizeof(reqbufs));
+  reqbufs.count  = ctrl.value + kMfcOutputBufferExtraCount;
+  reqbufs.type   = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  reqbufs.memory = V4L2_MEMORY_MMAP;
+  IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_REQBUFS, &reqbufs);
+
+  // Fill our free-buffers list, and create DMABUFs from them.
+  mfc_output_buffer_count_ = reqbufs.count;
+  mfc_output_buffer_map_.resize(mfc_output_buffer_count_);
+  for (int i = 0; i < mfc_output_buffer_count_; ++i) {
+    mfc_free_output_buffers_.push_back(i);
+
+    // Query for the MEMORY_MMAP pointer.
+    struct v4l2_plane planes[2];
+    struct v4l2_buffer buffer;
+    memset(&buffer, 0, sizeof(buffer));
+    memset(planes, 0, sizeof(planes));
+    buffer.index    = i;
+    buffer.type     = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+    buffer.memory   = V4L2_MEMORY_MMAP;
+    buffer.m.planes = planes;
+    buffer.length   = 2;
+    IOCTL_OR_ERROR_RETURN_FALSE(mfc_fd_, VIDIOC_QUERYBUF, &buffer);
+
+    // Get their user memory for GSC input.
+    for (int j = 0; j < 2; ++j) {
+      void* address = mmap(NULL, buffer.m.planes[j].length,
+          PROT_READ | PROT_WRITE, MAP_SHARED, mfc_fd_,
+          buffer.m.planes[j].m.mem_offset);
+      if (address == MAP_FAILED) {
+        DPLOG(ERROR) << "CreateMfcInputBuffers(): mmap() failed";
+        return false;
+      }
+      mfc_output_buffer_map_[i].address[j] = address;
+      mfc_output_buffer_map_[i].length[j] = buffer.m.planes[j].length;
+    }
+  }
+
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::CreateGscInputBuffers() {
+  DVLOG(3) << "CreateGscInputBuffers()";
+  DCHECK_EQ(decoder_state_, kInitialized);
+  DCHECK(!gsc_input_streamon_);
+  DCHECK_EQ(gsc_input_buffer_count_, 0);
+
+  struct v4l2_format format;
+  memset(&format, 0, sizeof(format));
+  format.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+  format.fmt.pix_mp.width  = frame_buffer_size_.width();
+  format.fmt.pix_mp.height = frame_buffer_size_.height();
+  format.fmt.pix_mp.pixelformat = mfc_output_buffer_pixelformat_;
+  format.fmt.pix_mp.plane_fmt[0].sizeimage = mfc_output_buffer_size_[0];
+  format.fmt.pix_mp.plane_fmt[1].sizeimage = mfc_output_buffer_size_[1];
+  // NV12MT_16X16 is a tiled format for which bytesperline doesn't make too much
+  // sense.  Convention seems to be to assume 8bpp for these tiled formats.
+  format.fmt.pix_mp.plane_fmt[0].bytesperline = frame_buffer_size_.width();
+  format.fmt.pix_mp.plane_fmt[1].bytesperline = frame_buffer_size_.width();
+  format.fmt.pix_mp.num_planes = 2;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_S_FMT, &format);
+
+  struct v4l2_control control;
+  memset(&control, 0, sizeof(control));
+  control.id = V4L2_CID_ROTATE;
+  control.value = 0;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_S_CTRL, &control);
+
+  memset(&control, 0, sizeof(control));
+  control.id = V4L2_CID_HFLIP;
+  control.value = 0;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_S_CTRL, &control);
+
+  memset(&control, 0, sizeof(control));
+  control.id = V4L2_CID_VFLIP;
+  control.value = 0;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_S_CTRL, &control);
+
+  memset(&control, 0, sizeof(control));
+  control.id = V4L2_CID_GLOBAL_ALPHA;
+  control.value = 255;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_S_CTRL, &control);
+
+  struct v4l2_requestbuffers reqbufs;
+  memset(&reqbufs, 0, sizeof(reqbufs));
+  reqbufs.count = kGscInputBufferCount;
+  reqbufs.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+  reqbufs.memory = V4L2_MEMORY_USERPTR;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_REQBUFS, &reqbufs);
+
+  gsc_input_buffer_count_ = reqbufs.count;
+  gsc_input_buffer_map_.resize(gsc_input_buffer_count_);
+  for (int i = 0; i < gsc_input_buffer_count_; ++i) {
+    gsc_free_input_buffers_.push_back(i);
+    gsc_input_buffer_map_[i].mfc_output = -1;
+  }
+
+  return true;
+}
+
+bool ExynosVideoDecodeAccelerator::CreateGscOutputBuffers() {
+  DVLOG(3) << "CreateGscOutputBuffers()";
+  DCHECK_EQ(decoder_state_, kInitialized);
+  DCHECK(!gsc_output_streamon_);
+  DCHECK_EQ(gsc_output_buffer_count_, 0);
+
+  // GSC outputs into the EGLImages we create from the textures we are
+  // assigned.  Assume RGBA8888 format.
+  struct v4l2_format format;
+  memset(&format, 0, sizeof(format));
+  format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  format.fmt.pix_mp.width  = frame_buffer_size_.width();
+  format.fmt.pix_mp.height = frame_buffer_size_.height();
+  format.fmt.pix_mp.pixelformat = V4L2_PIX_FMT_RGB32;
+  format.fmt.pix_mp.plane_fmt[0].sizeimage =
+      frame_buffer_size_.width() * frame_buffer_size_.height() * 4;
+  format.fmt.pix_mp.plane_fmt[0].bytesperline = frame_buffer_size_.width() * 4;
+  format.fmt.pix_mp.num_planes = 1;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_S_FMT, &format);
+
+  struct v4l2_requestbuffers reqbufs;
+  memset(&reqbufs, 0, sizeof(reqbufs));
+  reqbufs.count = kGscOutputBufferCount;
+  reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  reqbufs.memory = V4L2_MEMORY_DMABUF;
+  IOCTL_OR_ERROR_RETURN_FALSE(gsc_fd_, VIDIOC_REQBUFS, &reqbufs);
+
+  // We don't actually fill in the freelist or the map here.  That happens once
+  // we have actual usable buffers, after AssignPictureBuffers();
+  gsc_output_buffer_count_ = reqbufs.count;
+  gsc_output_buffer_map_.resize(gsc_output_buffer_count_);
+
+  DVLOG(3) << "CreateGscOutputBuffers(): ProvidePictureBuffers(): "
+           << "buffer_count=" << gsc_output_buffer_count_
+           << ", width=" << frame_buffer_size_.width()
+           << ", height=" << frame_buffer_size_.height();
+  child_message_loop_proxy_->PostTask(FROM_HERE, base::Bind(
+      &Client::ProvidePictureBuffers, client_, gsc_output_buffer_count_,
+      gfx::Size(frame_buffer_size_.width(), frame_buffer_size_.height()),
+      GL_TEXTURE_2D));
+
+  return true;
+}
+
+void ExynosVideoDecodeAccelerator::DestroyMfcInputBuffers() {
+  DVLOG(3) << "DestroyMfcInputBuffers()";
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+  DCHECK(!mfc_input_streamon_);
+
+  for (size_t i = 0; i < mfc_input_buffer_map_.size(); ++i) {
+    if (mfc_input_buffer_map_[i].address != NULL) {
+      munmap(mfc_input_buffer_map_[i].address,
+          mfc_input_buffer_map_[i].length);
+    }
+  }
+
+  struct v4l2_requestbuffers reqbufs;
+  memset(&reqbufs, 0, sizeof(reqbufs));
+  reqbufs.count = 0;
+  reqbufs.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+  reqbufs.memory = V4L2_MEMORY_MMAP;
+  if (ioctl(mfc_fd_, VIDIOC_REQBUFS, &reqbufs) != 0)
+    DPLOG(ERROR) << "DestroyMfcInputBuffers(): ioctl() failed: VIDIOC_REQBUFS";
+
+  mfc_input_buffer_map_.clear();
+  mfc_free_input_buffers_.clear();
+  mfc_input_buffer_count_ = 0;
+}
+
+void ExynosVideoDecodeAccelerator::DestroyMfcOutputBuffers() {
+  DVLOG(3) << "DestroyMfcOutputBuffers()";
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+  DCHECK(!mfc_output_streamon_);
+
+  for (size_t i = 0; i < mfc_output_buffer_map_.size(); ++i) {
+    if (mfc_output_buffer_map_[i].address[0] != NULL)
+      munmap(mfc_output_buffer_map_[i].address[0],
+          mfc_output_buffer_map_[i].length[0]);
+    if (mfc_output_buffer_map_[i].address[1] != NULL)
+      munmap(mfc_output_buffer_map_[i].address[1],
+          mfc_output_buffer_map_[i].length[1]);
+  }
+
+  struct v4l2_requestbuffers reqbufs;
+  memset(&reqbufs, 0, sizeof(reqbufs));
+  reqbufs.count = 0;
+  reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  reqbufs.memory = V4L2_MEMORY_MMAP;
+  if (ioctl(mfc_fd_, VIDIOC_REQBUFS, &reqbufs) != 0)
+    DPLOG(ERROR) << "DestroyMfcOutputBuffers() ioctl() failed: VIDIOC_REQBUFS";
+
+  mfc_output_buffer_map_.clear();
+  mfc_free_output_buffers_.clear();
+  mfc_output_buffer_count_ = 0;
+}
+
+void ExynosVideoDecodeAccelerator::DestroyGscInputBuffers() {
+  DVLOG(3) << "DestroyGscInputBuffers()";
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+  DCHECK(!gsc_input_streamon_);
+
+  struct v4l2_requestbuffers reqbufs;
+  memset(&reqbufs, 0, sizeof(reqbufs));
+  reqbufs.count = 0;
+  reqbufs.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+  reqbufs.memory = V4L2_MEMORY_DMABUF;
+  if (ioctl(gsc_fd_, VIDIOC_REQBUFS, &reqbufs) != 0)
+    DPLOG(ERROR) << "DestroyGscInputBuffers(): ioctl() failed: VIDIOC_REQBUFS";
+
+  gsc_input_buffer_map_.clear();
+  gsc_free_input_buffers_.clear();
+  gsc_input_buffer_count_ = 0;
+}
+
+void ExynosVideoDecodeAccelerator::DestroyGscOutputBuffers() {
+  DVLOG(3) << "DestroyGscOutputBuffers()";
+  DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
+  DCHECK(!gsc_output_streamon_);
+
+  if (gsc_output_buffer_map_.size() != 0) {
+    if (!make_context_current_.Run())
+      DLOG(ERROR) << "DestroyGscOutputBuffers(): "
+                  << "could not make context current";
+
+    size_t i = 0;
+    do {
+      GscOutputRecord& output_record = gsc_output_buffer_map_[i];
+      if (output_record.fd != -1)
+        close(output_record.fd);
+      if (output_record.egl_image != EGL_NO_IMAGE_KHR)
+        egl_destroy_image_khr(egl_display_, output_record.egl_image);
+      if (output_record.egl_sync != EGL_NO_SYNC_KHR)
+        egl_destroy_sync_khr(egl_display_, output_record.egl_sync);
+      if (client_)
+        client_->DismissPictureBuffer(output_record.picture_id);
+      ++i;
+    } while (i < gsc_output_buffer_map_.size());
+  }
+
+  struct v4l2_requestbuffers reqbufs;
+  memset(&reqbufs, 0, sizeof(reqbufs));
+  reqbufs.count = 0;
+  reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  reqbufs.memory = V4L2_MEMORY_DMABUF;
+  if (ioctl(gsc_fd_, VIDIOC_REQBUFS, &reqbufs) != 0)
+    DPLOG(ERROR) << "DestroyGscOutputBuffers(): ioctl() failed: VIDIOC_REQBUFS";
+
+  gsc_output_buffer_map_.clear();
+  gsc_free_output_buffers_.clear();
+  gsc_output_buffer_count_ = 0;
+}
+
+}  // namespace content