Switch DRM platform to using a separate thread

ui/ozone/platform/drm/gpu/drm_thread.cc

Index: ui/ozone/platform/drm/gpu/drm_thread.cc
diff --git a/ui/ozone/platform/drm/gpu/drm_thread.cc b/ui/ozone/platform/drm/gpu/drm_thread.cc
new file mode 100644
index 0000000000000000000000000000000000000000..451293d45d0b652beab4c7f7d1b6e9e4b4cfa4b4
--- /dev/null
+++ b/ui/ozone/platform/drm/gpu/drm_thread.cc
@@ -0,0 +1,227 @@
+// Copyright 2015 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 "ui/ozone/platform/drm/gpu/drm_thread.h"
+
+#include "base/command_line.h"
+#include "base/thread_task_runner_handle.h"
+#include "ui/ozone/platform/drm/gpu/drm_buffer.h"
+#include "ui/ozone/platform/drm/gpu/drm_device_generator.h"
+#include "ui/ozone/platform/drm/gpu/drm_device_manager.h"
+#include "ui/ozone/platform/drm/gpu/drm_gpu_display_manager.h"
+#include "ui/ozone/platform/drm/gpu/drm_window.h"
+#include "ui/ozone/platform/drm/gpu/drm_window_proxy.h"
+#include "ui/ozone/platform/drm/gpu/gbm_buffer.h"
+#include "ui/ozone/platform/drm/gpu/gbm_device.h"
+#include "ui/ozone/platform/drm/gpu/gbm_surface_factory.h"
+#include "ui/ozone/platform/drm/gpu/proxy_helpers.h"
+#include "ui/ozone/platform/drm/gpu/screen_manager.h"
+#include "ui/ozone/public/ozone_switches.h"
+
+namespace ui {
+
+namespace {
+
+class GbmBufferGenerator : public ScanoutBufferGenerator {
+ public:
+  GbmBufferGenerator() {}
+  ~GbmBufferGenerator() override {}
+
+  // ScanoutBufferGenerator:
+  scoped_refptr<ScanoutBuffer> Create(const scoped_refptr<DrmDevice>& drm,
+                                      gfx::BufferFormat format,
+                                      const gfx::Size& size) override {
+    scoped_refptr<GbmDevice> gbm(static_cast<GbmDevice*>(drm.get()));
+    return GbmBuffer::CreateBuffer(gbm, format, size,
+                                   gfx::BufferUsage::SCANOUT);
+  }
+
+ protected:
+  DISALLOW_COPY_AND_ASSIGN(GbmBufferGenerator);
+};
+
+class GbmDeviceGenerator : public DrmDeviceGenerator {
+ public:
+  GbmDeviceGenerator(bool use_atomic) : use_atomic_(use_atomic) {}
+  ~GbmDeviceGenerator() override {}
+
+  // DrmDeviceGenerator:
+  scoped_refptr<DrmDevice> CreateDevice(const base::FilePath& path,
+                                        base::File file) override {
+    scoped_refptr<DrmDevice> drm = new GbmDevice(path, file.Pass());
+    if (drm->Initialize(use_atomic_))
+      return drm;
+
+    return nullptr;
+  }
+
+ private:
+  bool use_atomic_;
+
+  DISALLOW_COPY_AND_ASSIGN(GbmDeviceGenerator);
+};
+
+}  // namespace
+
+DrmThread::DrmThread() : base::Thread("DrmThread") {}
+
+DrmThread::~DrmThread() {
+  Stop();
+}
+
+void DrmThread::Start() {
+  if (!StartWithOptions(base::Thread::Options(base::MessageLoop::TYPE_IO, 0)))
+    LOG(FATAL) << "Failed to create DRM thread";
+}
+
+void DrmThread::Init() {
+  bool use_atomic = false;
+#if defined(USE_DRM_ATOMIC)
+  use_atomic = true;
+#endif
+
+  device_manager_.reset(new DrmDeviceManager(
+      make_scoped_ptr(new GbmDeviceGenerator(use_atomic))));
+  buffer_generator_.reset(new GbmBufferGenerator());
+  screen_manager_.reset(new ScreenManager(buffer_generator_.get()));
+
+  display_manager_.reset(
+      new DrmGpuDisplayManager(screen_manager_.get(), device_manager_.get()));
+}
+
+scoped_ptr<DrmWindowProxy> DrmThread::CreateWindowProxy(

[spang, 2015/09/29 22:55:37]

I think it is inconsistent to put it here. In every other case, you're posting
to DrmThread from the caller. This is the only place that DrmThread does its own
post.

If you move it to GbmSurfaceFactory then it won't an exception anymore, and you
can all the non-lifecycle methods aren't thread safe (well, excpet
task_runner()).

WDYT?

[dnicoara, 2015/09/30 15:17:57]

Yeah, that was bugging me a bit too. The DrmWindowProxy is still bugging me a
bit though. I find it bad to have the proxy creation and the window operation
calls all on DrmThread. The alternatives I could think of are:
1) Have the call to DrmThread::CreateWindow be a sync call, though the downside
is that it would block GPU IO.
2) Have something like DrmThread::Flush and wait on that in
GbmSurfaceFactory::CreateSurfacelessEGLSurfaceForWidget(). Then the whole
DrmWindowProxy can be deleted. The downside is that this is feels like a big
hammer.

What's your take on this?

+    gfx::AcceleratedWidget widget) {
+  scoped_ptr<DrmWindowProxy> window;
+  // The creation is synchronous on the DRM thread since it needs to make sure
+  // that the window is created on the DRM thread before continuing. This is
+  // required since the DrmDeviceManager is accessed on the GPU IO thread
+  // without a posted task which could result in invalid lookups for the widget
+  // if the window creation is still pending.
+  PostSyncTask(task_runner(),
+               base::Bind(&DrmThread::CreateWindowProxyOnThread,
+                          base::Unretained(this), widget, &window));
+  return window;
+}
+
+void DrmThread::SchedulePageFlip(gfx::AcceleratedWidget widget,
+                                 const std::vector<OverlayPlane>& planes,
+                                 const SwapCompletionCallback& callback) {
+  DrmWindow* window = screen_manager_->GetWindow(widget);
+  if (window)
+    window->SchedulePageFlip(planes, callback);
+}
+
+void DrmThread::GetVSyncParameters(
+    gfx::AcceleratedWidget widget,
+    const gfx::VSyncProvider::UpdateVSyncCallback& callback) {
+  DrmWindow* window = screen_manager_->GetWindow(widget);
+  if (window)
+    window->GetVSyncParameters(callback);
+}
+
+void DrmThread::OnCreateWindow(gfx::AcceleratedWidget widget) {

[spang, 2015/09/29 22:55:37]

We should use the imperative

CreateWindow()

OnCreateWindow says "I'm responding to CreateWindow" which I think is fairly
misleading here. There's two events:

(1) delivering the CreateWindow IPC message
(2) actually creating the window

It's much clearer to refer to (2) here, and ignore (1) since it's not as
relevant. The only reason the older code said "On" was because it was directly
responding to (1).

Same goes for the rest of the commands below.

[dnicoara, 2015/09/30 15:17:57]

Done. Sounds reasonable.

+  scoped_ptr<DrmWindow> window(
+      new DrmWindow(widget, device_manager_.get(), screen_manager_.get()));
+  window->Initialize();
+  screen_manager_->AddWindow(widget, window.Pass());
+}
+
+void DrmThread::OnDestroyWindow(gfx::AcceleratedWidget widget) {
+  scoped_ptr<DrmWindow> window = screen_manager_->RemoveWindow(widget);
+  window->Shutdown();
+}
+
+void DrmThread::OnWindowBoundsChanged(gfx::AcceleratedWidget widget,
+                                      const gfx::Rect& bounds) {
+  screen_manager_->GetWindow(widget)->OnBoundsChanged(bounds);
+}
+
+void DrmThread::OnCursorSet(gfx::AcceleratedWidget widget,
+                            const std::vector<SkBitmap>& bitmaps,
+                            const gfx::Point& location,
+                            int frame_delay_ms) {
+  screen_manager_->GetWindow(widget)
+      ->SetCursor(bitmaps, location, frame_delay_ms);
+}
+
+void DrmThread::OnCursorMove(gfx::AcceleratedWidget widget,
+                             const gfx::Point& location) {
+  screen_manager_->GetWindow(widget)->MoveCursor(location);
+}
+
+void DrmThread::OnCheckOverlayCapabilities(
+    gfx::AcceleratedWidget widget,
+    const std::vector<OverlayCheck_Params>& overlays,
+    const base::Callback<void(gfx::AcceleratedWidget, bool)>& callback) {
+  callback.Run(widget, screen_manager_->GetWindow(widget)
+                           ->TestPageFlip(overlays, buffer_generator_.get()));
+}
+
+void DrmThread::OnRefreshNativeDisplays(
+    const base::Callback<void(const std::vector<DisplaySnapshot_Params>&)>&
+        callback) {
+  callback.Run(display_manager_->GetDisplays());
+}
+
+void DrmThread::OnConfigureNativeDisplay(
+    int64_t id,
+    const DisplayMode_Params& mode,
+    const gfx::Point& origin,
+    const base::Callback<void(int64_t, bool)>& callback) {
+  callback.Run(id, display_manager_->ConfigureDisplay(id, mode, origin));
+}
+
+void DrmThread::OnDisableNativeDisplay(
+    int64_t id,
+    const base::Callback<void(int64_t, bool)>& callback) {
+  callback.Run(id, display_manager_->DisableDisplay(id));
+}
+
+void DrmThread::OnTakeDisplayControl(
+    const base::Callback<void(bool)>& callback) {
+  callback.Run(display_manager_->TakeDisplayControl());
+}
+
+void DrmThread::OnRelinquishDisplayControl(
+    const base::Callback<void(bool)>& callback) {
+  display_manager_->RelinquishDisplayControl();
+  callback.Run(true);
+}
+
+void DrmThread::OnAddGraphicsDevice(const base::FilePath& path,
+                                    const base::FileDescriptor& fd) {
+  device_manager_->AddDrmDevice(path, fd);
+}
+
+void DrmThread::OnRemoveGraphicsDevice(const base::FilePath& path) {
+  device_manager_->RemoveDrmDevice(path);
+}
+
+void DrmThread::OnGetHDCPState(
+    int64_t display_id,
+    const base::Callback<void(int64_t, bool, HDCPState)>& callback) {
+  HDCPState state = HDCP_STATE_UNDESIRED;
+  bool success = display_manager_->GetHDCPState(display_id, &state);
+  callback.Run(display_id, success, state);
+}
+
+void DrmThread::OnSetHDCPState(
+    int64_t display_id,
+    HDCPState state,
+    const base::Callback<void(int64_t, bool)>& callback) {
+  callback.Run(display_id, display_manager_->SetHDCPState(display_id, state));
+}
+
+void DrmThread::OnSetGammaRamp(int64_t id,
+                               const std::vector<GammaRampRGBEntry>& lut) {
+  display_manager_->SetGammaRamp(id, lut);
+}
+
+void DrmThread::CreateWindowProxyOnThread(gfx::AcceleratedWidget widget,
+                                          scoped_ptr<DrmWindowProxy>* window) {
+  if (screen_manager_->GetWindow(widget))
+    window->reset(new DrmWindowProxy(widget, this));
+}
+
+}  // namespace ui