[Ozone-DRI] Reuse framebuffer when re-enabling CRTC

BUG=446312
NOTRY=true

Review URL: https://codereview.chromium.org/838633002

Cr-Commit-Position: refs/heads/master@{#310197}

ui/ozone/platform/dri/hardware_display_controller.cc

@@ -48,6 +48,7 @@ void HandlePageFlipEvent(int fd,
 HardwareDisplayController::HardwareDisplayController(
     scoped_ptr<CrtcController> controller)
     : is_disabled_(true) {
+  memset(&mode_, 0, sizeof(mode_));
   AddCrtc(controller.Pass());
 }
 
@@ -75,12 +76,8 @@ bool HardwareDisplayController::Enable() {
   TRACE_EVENT0("dri", "HDC::Enable");
   DCHECK(!current_planes_.empty());
   const OverlayPlane* primary = OverlayPlane::GetPrimaryPlane(current_planes_);
-  DCHECK(primary->buffer.get());
-  bool status = true;
-  for (size_t i = 0; i < crtc_controllers_.size(); ++i)
-    status &= crtc_controllers_[i]->Modeset(*primary, mode_);
 
-  return status;
+  return Modeset(*primary, mode_);
 }
 
 void HardwareDisplayController::Disable() {

ui/ozone/platform/dri/screen_manager.cc

@@ -109,8 +109,19 @@ bool ScreenManager::ConfigureDisplayController(uint32_t crtc,
   // If nothing changed just enable the controller. Note, we perform an exact
   // comparison on the mode since the refresh rate may have changed.
   if (SameMode(mode, controller->get_mode()) &&
-      origin == controller->origin() && !controller->IsDisabled())
+      origin == controller->origin()) {
+    if (controller->IsDisabled()) {
+      HardwareDisplayControllers::iterator mirror =
+          FindActiveDisplayControllerByLocation(modeset_bounds);
+      // If there is an active controller at the same location then start mirror
+      // mode.
+      if (mirror != controllers_.end())
+        return HandleMirrorMode(it, mirror, crtc, connector);
+    }
+
+    // Just re-enable the controller to re-use the current state.
     return controller->Enable();
+  }
 
   // Either the mode or the location of the display changed, so exit mirror
   // mode and configure the display independently. If the caller still wants

ui/ozone/platform/dri/screen_manager_unittest.cc

@@ -139,11 +139,16 @@ TEST_F(ScreenManagerTest, CheckDuplicateConfiguration) {
                                               kPrimaryConnector,
                                               GetPrimaryBounds().origin(),
                                               kDefaultMode);
+  uint32_t framebuffer = dri_->current_framebuffer();
+
   screen_manager_->ConfigureDisplayController(kPrimaryCrtc,
                                               kPrimaryConnector,
                                               GetPrimaryBounds().origin(),
                                               kDefaultMode);
 
+  // Should reuse existing framebuffer.
+  EXPECT_EQ(framebuffer, dri_->current_framebuffer());
+
   EXPECT_TRUE(screen_manager_->GetDisplayController(GetPrimaryBounds()));
   EXPECT_FALSE(screen_manager_->GetDisplayController(GetSecondaryBounds()));
 }
@@ -275,3 +280,48 @@ TEST_F(ScreenManagerTest, DoNotEnterMirrorModeUnlessSameBounds) {
   EXPECT_FALSE(
       screen_manager_->GetDisplayController(GetPrimaryBounds())->IsMirrored());
 }
+
+TEST_F(ScreenManagerTest, ReuseFramebufferIfDisabledThenReEnabled) {
+  screen_manager_->AddDisplayController(dri_.get(), kPrimaryCrtc,
+                                        kPrimaryConnector);
+  screen_manager_->ConfigureDisplayController(kPrimaryCrtc, kPrimaryConnector,
+                                              GetPrimaryBounds().origin(),
+                                              kDefaultMode);
+  uint32_t framebuffer = dri_->current_framebuffer();
+
+  screen_manager_->DisableDisplayController(kPrimaryCrtc);
+  EXPECT_EQ(0u, dri_->current_framebuffer());
+
+  screen_manager_->ConfigureDisplayController(kPrimaryCrtc, kPrimaryConnector,
+                                              GetPrimaryBounds().origin(),
+                                              kDefaultMode);
+
+  // Should reuse existing framebuffer.
+  EXPECT_EQ(framebuffer, dri_->current_framebuffer());
+}
+
+TEST_F(ScreenManagerTest, CheckMirrorModeAfterBeginReEnabled) {
+  screen_manager_->AddDisplayController(dri_.get(), kPrimaryCrtc,
+                                        kPrimaryConnector);
+  screen_manager_->ConfigureDisplayController(kPrimaryCrtc, kPrimaryConnector,
+                                              GetPrimaryBounds().origin(),
+                                              kDefaultMode);
+  screen_manager_->DisableDisplayController(kPrimaryCrtc);
+
+  screen_manager_->AddDisplayController(dri_.get(), kSecondaryCrtc,
+                                        kSecondaryConnector);
+  screen_manager_->ConfigureDisplayController(
+      kSecondaryCrtc, kSecondaryConnector, GetPrimaryBounds().origin(),
+      kDefaultMode);
+
+  base::WeakPtr<ui::HardwareDisplayController> controller =
+      screen_manager_->GetDisplayController(GetPrimaryBounds());
+  EXPECT_TRUE(controller);
+  EXPECT_FALSE(controller->IsMirrored());
+
+  screen_manager_->ConfigureDisplayController(kPrimaryCrtc, kPrimaryConnector,
+                                              GetPrimaryBounds().origin(),
+                                              kDefaultMode);
+  EXPECT_TRUE(controller);
+  EXPECT_TRUE(controller->IsMirrored());
+}

ui/ozone/platform/dri/test/mock_dri_wrapper.cc

@@ -105,6 +105,11 @@ bool MockDriWrapper::SetCrtc(drmModeCrtc* crtc,
   return true;
 }
 
+bool MockDriWrapper::DisableCrtc(uint32_t crtc_id) {
+  current_framebuffer_ = 0;
+  return true;
+}
+
 ScopedDrmConnectorPtr MockDriWrapper::GetConnector(uint32_t connector_id) {
   return ScopedDrmConnectorPtr(DrmAllocator<drmModeConnector>());
 }

ui/ozone/platform/dri/test/mock_dri_wrapper.h

@@ -63,6 +63,7 @@ class MockDriWrapper : public ui::DriWrapper {
                std::vector<uint32_t> connectors,
                drmModeModeInfo* mode) override;
   bool SetCrtc(drmModeCrtc* crtc, std::vector<uint32_t> connectors) override;
+  bool DisableCrtc(uint32_t crtc_id) override;
   ScopedDrmConnectorPtr GetConnector(uint32_t connector_id) override;
   bool AddFramebuffer(uint32_t width,
                       uint32_t height,