ozone: Disable primary plane when HDC gets disabled

When HardwareDisplayController get disabled we should disable all
planes, including the primary, by setting the fb to 0.
Not doing so can have privacy implications, where we might end up
reading back the last fb when modesetting again and show to the user
contents that should not be seen.

In the past, when legacy modesetting was used, the fb associated with
the crtc was set to 0 when calling drmModeSetCrtc. After that we'd
disable the other planes but the primary.

Since we moved to the atomic API for modesetting, we now need to
explicitly set to 0 the fb of the primary plane along the other planes.


Bug: 1102859
Test: Close/open the lid on krane, no old contents are visible.
Change-Id: Ib93347b59cc847898c0713f81ad0903773699b07
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2412974
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Gil Dekel <gildekel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807476}

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

@@ -400,11 +400,10 @@ TEST_F(HardwareDisplayControllerTest, PlaneStateAfterRemoveCrtc) {
   EXPECT_EQ(kPrimaryCrtc, primary_crtc_plane->owning_crtc());
   EXPECT_EQ(kSecondaryCrtc, secondary_crtc_plane->owning_crtc());
 
-  // Removing the crtc should not free the plane or change ownership.
+  // Removing the crtc should free the plane.
   std::unique_ptr<ui::CrtcController> crtc =
       controller_->RemoveCrtc(drm_, kPrimaryCrtc);
-  EXPECT_TRUE(primary_crtc_plane->in_use());
-  EXPECT_EQ(kPrimaryCrtc, primary_crtc_plane->owning_crtc());
+  EXPECT_FALSE(primary_crtc_plane->in_use());
   EXPECT_TRUE(secondary_crtc_plane->in_use());
   EXPECT_EQ(kSecondaryCrtc, secondary_crtc_plane->owning_crtc());
 
@@ -414,8 +413,7 @@ TEST_F(HardwareDisplayControllerTest, PlaneStateAfterRemoveCrtc) {
   drm_->RunCallbacks();
   EXPECT_EQ(gfx::SwapResult::SWAP_ACK, last_swap_result_);
   EXPECT_EQ(2, page_flips_);
-  EXPECT_TRUE(primary_crtc_plane->in_use());
-  EXPECT_EQ(kPrimaryCrtc, primary_crtc_plane->owning_crtc());
+  EXPECT_FALSE(primary_crtc_plane->in_use());
   EXPECT_TRUE(secondary_crtc_plane->in_use());
   EXPECT_EQ(kSecondaryCrtc, secondary_crtc_plane->owning_crtc());
 }
@@ -474,8 +472,7 @@ TEST_F(HardwareDisplayControllerTest, PlaneStateAfterAddCrtc) {
   drm_->RunCallbacks();
   EXPECT_EQ(gfx::SwapResult::SWAP_ACK, last_swap_result_);
   EXPECT_EQ(2, page_flips_);
-  EXPECT_TRUE(primary_crtc_plane->in_use());
-  EXPECT_EQ(kPrimaryCrtc, primary_crtc_plane->owning_crtc());
+  EXPECT_FALSE(primary_crtc_plane->in_use());
 
   // We reset state of plane here to test that the plane was actually added to
   // hdc_controller. In which case, the right state should be set to plane
@@ -588,6 +585,6 @@ TEST_F(HardwareDisplayControllerTest, Disable) {
     if (plane->in_use())
       planes_in_use++;
   }
-  // Only the primary plane is in use.
-  ASSERT_EQ(1, planes_in_use);
+  // No plane should be in use.
+  ASSERT_EQ(0, planes_in_use);
 }

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

@@ -196,8 +196,6 @@ bool HardwareDisplayPlaneManagerAtomic::Commit(
 bool HardwareDisplayPlaneManagerAtomic::DisableOverlayPlanes(
     HardwareDisplayPlaneList* plane_list) {
   for (HardwareDisplayPlane* plane : plane_list->old_plane_list) {
-    if (plane->type() != HardwareDisplayPlane::kOverlay)
-      continue;
     plane->set_in_use(false);
     plane->set_owning_crtc(0);