ozone/drm: Disable planes when removing a crtc.

When HardwareDisplayController::RemoveCrtc is called, planes in old_plane_list,
that is the list of planes last committed for scanout, should be disabled.

Before this patch the planes would not be disabled and would unexpectedly show up
on displays where the old crtc would get reassigned.

Bug: b/72749390
Test: plugged in a secondary monitor while an overlay is displayed on the primary.
Change-Id: I76675a765d0ed9572baaf457060c2d7dac619614
Reviewed-on: https://chromium-review.googlesource.com/924347
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: David Reveman <reveman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537491}

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

@@ -224,39 +224,51 @@ void HardwareDisplayController::AddCrtc(
 std::unique_ptr<CrtcController> HardwareDisplayController::RemoveCrtc(
     const scoped_refptr<DrmDevice>& drm,
     uint32_t crtc) {
-  for (auto it = crtc_controllers_.begin(); it != crtc_controllers_.end();
-       ++it) {
-    if ((*it)->drm() == drm && (*it)->crtc() == crtc) {
-      std::unique_ptr<CrtcController> controller(std::move(*it));
-      crtc_controllers_.erase(it);
-
-      // Remove entry from |owned_hardware_planes_| iff no other crtcs share it.
-      bool found = false;
-      for (auto it = crtc_controllers_.begin(); it != crtc_controllers_.end();
-           ++it) {
-        if ((*it)->drm() == controller->drm()) {
-          found = true;
-          break;
-        }
-      }
-      if (found) {
-        std::vector<HardwareDisplayPlane*> all_planes;
-        HardwareDisplayPlaneList* plane_list =
-            owned_hardware_planes_[drm.get()].get();
-        all_planes.swap(plane_list->old_plane_list);
-        for (auto* plane : all_planes) {
-          if (plane->owning_crtc() != crtc)
-            plane_list->old_plane_list.push_back(plane);
-        }
-      } else {
-        owned_hardware_planes_.erase(controller->drm().get());
-      }
-
-      return controller;
-    }
+  auto controller_it = std::find_if(
+      crtc_controllers_.begin(), crtc_controllers_.end(),
+      [drm, crtc](const std::unique_ptr<CrtcController>& crtc_controller) {
+        return crtc_controller->drm() == drm && crtc_controller->crtc() == crtc;
+      });
+  if (controller_it == crtc_controllers_.end())
+    return nullptr;
+
+  std::unique_ptr<CrtcController> controller(std::move(*controller_it));
+  crtc_controllers_.erase(controller_it);
+
+  // Remove and disable only the planes owned by the CRTC we just
+  // removed.
+  std::vector<HardwareDisplayPlane*>& old_plane_list =
+      owned_hardware_planes_[drm.get()]->old_plane_list;
+
+  // Move all the planes that have been committed in the last pageflip for this
+  // CRTC at the end of the collection.
+  auto first_plane_to_disable_it =
+      std::partition(old_plane_list.begin(), old_plane_list.end(),
+                     [crtc](const HardwareDisplayPlane* plane) {
+                       return plane->owning_crtc() != crtc;
+                     });
+
+  // Disable the planes enabled with the last commit on |crtc|, otherwise
+  // the planes will be visible if the crtc is reassigned to another connector.
+  HardwareDisplayPlaneList hardware_plane_list;
+  std::copy(first_plane_to_disable_it, old_plane_list.end(),
+            std::back_inserter(hardware_plane_list.old_plane_list));
+  drm->plane_manager()->DisableOverlayPlanes(&hardware_plane_list);
+
+  // If it was the only CRTC for this drm device, we can remove the hardware
+  // planes list in |owned_hardware_planes_|.
+  if (std::find_if(crtc_controllers_.begin(), crtc_controllers_.end(),
+                   [drm](const std::unique_ptr<CrtcController>& crtc) {
+                     return crtc->drm() == drm;
+                   }) == crtc_controllers_.end()) {
+    owned_hardware_planes_.erase(controller->drm().get());
+  } else {
+    // Otherwise we can remove the planes assigned to |crtc| but we can't
+    // remove the entry in |owned_hardware_planes_|.
+    old_plane_list.erase(first_plane_to_disable_it, old_plane_list.end());
   }
 
-  return nullptr;
+  return controller;
 }
 
 bool HardwareDisplayController::HasCrtc(const scoped_refptr<DrmDevice>& drm,