ozone: Disable overlays on HDC::Disable.

HDC::Disable currently calls drmModeSetCrtc, that disable the primary
plane, but not additional overlays.

This means that when disabling an HDC and then re-enabling, after the
new modeset, and before a new pageflip, you can see an overlay that was
set with the old pageflip.

This CL makes sure to disable all planes when disabling an HDC.

Bug: 763736
Change-Id: I30ec7eb9ec1323474c21335aaadd1ce2bb250a89
Reviewed-on: https://chromium-review.googlesource.com/680476
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: David Reveman <reveman@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504094}

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

@@ -69,6 +69,12 @@ bool HardwareDisplayController::Enable(const OverlayPlane& primary) {
 
 void HardwareDisplayController::Disable() {
   TRACE_EVENT0("drm", "HDC::Disable");
+  // Disable all the planes by scheduling a pageflip with an empty plane_list.
+  // This is necessary since drmModeSetCrtc, that is called by
+  // controller->Disable(), will not disable overlays.
+  const OverlayPlaneList plane_list;
+  ActualSchedulePageFlip(plane_list, false, base::BindOnce(&EmptyFlipCallback));
+
   for (const auto& controller : crtc_controllers_)
     controller->Disable();
 
@@ -96,18 +102,12 @@ bool HardwareDisplayController::ActualSchedulePageFlip(
 
   DCHECK(!is_disabled_);
 
-  // Ignore requests with no planes to schedule.
-  if (plane_list.empty()) {
-    std::move(callback).Run(gfx::SwapResult::SWAP_ACK);
-    return true;
-  }
-
   OverlayPlaneList pending_planes = plane_list;
   std::sort(pending_planes.begin(), pending_planes.end(),
             [](const OverlayPlane& l, const OverlayPlane& r) {
               return l.z_order < r.z_order;
             });
-  if (pending_planes.front().z_order < 0) {
+  if (pending_planes.size() && pending_planes.front().z_order < 0) {
     std::move(callback).Run(gfx::SwapResult::SWAP_FAILED);
     return false;
   }

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

@@ -452,3 +452,43 @@ TEST_F(HardwareDisplayControllerTest, RemoveCrtcMidPageFlip) {
   EXPECT_EQ(gfx::SwapResult::SWAP_ACK, last_swap_result_);
   EXPECT_EQ(1, page_flips_);
 }
+
+TEST_F(HardwareDisplayControllerTest, EmptyPageFlip) {
+  ui::OverlayPlane plane1(new ui::MockScanoutBuffer(kDefaultModeSize));
+  EXPECT_TRUE(controller_->Modeset(plane1, kDefaultMode));
+  std::vector<ui::OverlayPlane> planes(1, plane1);
+  controller_->SchedulePageFlip(
+      planes, base::Bind(&HardwareDisplayControllerTest::PageFlipCallback,
+                         base::Unretained(this)));
+  drm_->RunCallbacks();
+  EXPECT_EQ(gfx::SwapResult::SWAP_ACK, last_swap_result_);
+  EXPECT_EQ(1, page_flips_);
+}
+
+TEST_F(HardwareDisplayControllerTest, Disable) {
+  ui::OverlayPlane plane1(scoped_refptr<ui::ScanoutBuffer>(
+      new ui::MockScanoutBuffer(kDefaultModeSize)));
+  EXPECT_TRUE(controller_->Modeset(plane1, kDefaultMode));
+
+  ui::OverlayPlane plane2(new ui::MockScanoutBuffer(kOverlaySize), 1,
+                          gfx::OVERLAY_TRANSFORM_NONE, gfx::Rect(kOverlaySize),
+                          gfx::RectF(kDefaultModeSizeF));
+  std::vector<ui::OverlayPlane> planes;
+  planes.push_back(plane1);
+  planes.push_back(plane2);
+
+  controller_->SchedulePageFlip(
+      planes, base::Bind(&HardwareDisplayControllerTest::PageFlipCallback,
+                         base::Unretained(this)));
+  drm_->RunCallbacks();
+  EXPECT_EQ(gfx::SwapResult::SWAP_ACK, last_swap_result_);
+  EXPECT_EQ(1, page_flips_);
+
+  controller_->Disable();
+
+  const ui::HardwareDisplayPlane* owned_plane = nullptr;
+  for (const auto& plane : drm_->plane_manager()->planes())
+    if (plane->in_use())
+      owned_plane = plane.get();
+  ASSERT_FALSE(owned_plane);
+}