[Ozone-DRI] Listen for swap events

ui/ozone/platform/dri/hardware_display_controller.cc

Index: ui/ozone/platform/dri/hardware_display_controller.cc
diff --git a/ui/ozone/platform/dri/hardware_display_controller.cc b/ui/ozone/platform/dri/hardware_display_controller.cc
index 275467db9ea95903a584fd3aca813dfa5f42e0f4..375cc82b77c171d095316f5ddaeafd8bb912eddd 100644
--- a/ui/ozone/platform/dri/hardware_display_controller.cc
+++ b/ui/ozone/platform/dri/hardware_display_controller.cc
@@ -22,28 +22,14 @@
 
 namespace ui {
 
-namespace {
-
-// DRM callback on page flip events. This callback is triggered after the
-// page flip has happened and the backbuffer is now the new frontbuffer
-// The old frontbuffer is no longer used by the hardware and can be used for
-// future draw operations.
-//
-// |device| will contain a reference to the |ScanoutSurface| object which
-// the event belongs to.
-//
-// TODO(dnicoara) When we have a FD handler for the DRM calls in the message
-// loop, we can move this function in the handler.
-void HandlePageFlipEvent(int fd,
-                         unsigned int frame,
-                         unsigned int seconds,
-                         unsigned int useconds,
-                         void* controller) {
-  static_cast<CrtcController*>(controller)
-      ->OnPageFlipEvent(frame, seconds, useconds);
-}
-
-}  // namespace
+HardwareDisplayController::PageFlipRequest::PageFlipRequest(
+    const OverlayPlaneList& planes,
+    const base::Closure& callback)
+    : planes(planes), callback(callback) {
+}
+
+HardwareDisplayController::PageFlipRequest::~PageFlipRequest() {
+}
 
 HardwareDisplayController::HardwareDisplayController(
     scoped_ptr<CrtcController> controller)
@@ -55,6 +41,7 @@ HardwareDisplayController::HardwareDisplayController(
 HardwareDisplayController::~HardwareDisplayController() {
   // Reset the cursor.
   UnsetCursor();
+  ClearPendingRequests();
 }
 
 bool HardwareDisplayController::Modeset(const OverlayPlane& primary,
@@ -65,10 +52,19 @@ bool HardwareDisplayController::Modeset(const OverlayPlane& primary,
   for (size_t i = 0; i < crtc_controllers_.size(); ++i)
     status &= crtc_controllers_[i]->Modeset(primary, mode);
 
-  current_planes_ = std::vector<OverlayPlane>(1, primary);
-  pending_planes_.clear();
   is_disabled_ = false;
   mode_ = mode;
+
+  current_planes_ = std::vector<OverlayPlane>(1, primary);
+  pending_planes_.clear();
+  ClearPendingRequests();
+
+  // Because a page flip is pending we need to leave some state for the
+  // callback. We use the modeset state since it is the only valid state.
+  if (HasPendingPageFlips())
+    requests_.push_back(
+        PageFlipRequest(current_planes_, base::Bind(&base::DoNothing)));
+
   return status;
 }
 
@@ -92,59 +88,30 @@ void HardwareDisplayController::QueueOverlayPlane(const OverlayPlane& plane) {
   pending_planes_.push_back(plane);
 }
 
-bool HardwareDisplayController::SchedulePageFlip() {
-  DCHECK(!pending_planes_.empty());
+bool HardwareDisplayController::SchedulePageFlip(
+    const base::Closure& callback) {
+  TRACE_EVENT0("dri", "HDC::SchedulePageFlip");
 
-  if (is_disabled_)
+  // Ignore requests with no planes to schedule.
+  if (pending_planes_.empty()) {
+    callback.Run();
     return true;
-
-  std::sort(pending_planes_.begin(), pending_planes_.end(),
-            [](const OverlayPlane& l, const OverlayPlane& r) {
-    return l.z_order < r.z_order;
-  });
-
-  bool status = true;
-  for (size_t i = 0; i < crtc_controllers_.size(); ++i) {
-    status &= crtc_controllers_[i]->SchedulePageFlip(
-        owned_hardware_planes_.get(crtc_controllers_[i]->drm()),
-        pending_planes_);
-  }
-
-  for (const auto& planes : owned_hardware_planes_) {
-    if (!planes.first->plane_manager()->Commit(planes.second)) {
-      status = false;
-    }
   }
 
-  return status;
-}
-
-void HardwareDisplayController::WaitForPageFlipEvent() {
-  TRACE_EVENT0("dri", "HDC::WaitForPageFlipEvent");
+  requests_.push_back(PageFlipRequest(pending_planes_, callback));
+  pending_planes_.clear();
 
-  drmEventContext drm_event;
-  drm_event.version = DRM_EVENT_CONTEXT_VERSION;
-  drm_event.page_flip_handler = HandlePageFlipEvent;
-  drm_event.vblank_handler = NULL;
+  // A request is being serviced right now.
+  if (HasPendingPageFlips())
+    return true;
 
-  bool has_pending_page_flips = false;
-  // Wait for the page-flips to complete.
-  for (size_t i = 0; i < crtc_controllers_.size(); ++i) {
-    // In mirror mode the page flip callbacks can happen in different order than
-    // scheduled, so we need to make sure that the event for the current CRTC is
-    // processed before moving to the next CRTC.
-    while (crtc_controllers_[i]->page_flip_pending()) {
-      has_pending_page_flips = true;
-      crtc_controllers_[i]->drm()->HandleEvent(drm_event);
-    }
-  }
+  bool status = ActualSchedulePageFlip();
 
-  // In case there are no pending pageflips do not replace the current planes
-  // since they are still being used.
-  if (has_pending_page_flips)
-    current_planes_.swap(pending_planes_);
+  // No page flip event on failure so discard failed request.
+  if (!status)
+    requests_.pop_front();
 
-  pending_planes_.clear();
+  return status;
 }
 
 bool HardwareDisplayController::SetCursor(
@@ -183,6 +150,7 @@ void HardwareDisplayController::AddCrtc(scoped_ptr<CrtcController> controller) {
   owned_hardware_planes_.add(
       controller->drm(),
       scoped_ptr<HardwareDisplayPlaneList>(new HardwareDisplayPlaneList()));
+  controller->AddObserver(this);
   crtc_controllers_.push_back(controller.release());
 }
 
@@ -193,9 +161,6 @@ scoped_ptr<CrtcController> HardwareDisplayController::RemoveCrtc(
     if ((*it)->crtc() == crtc) {
       scoped_ptr<CrtcController> controller(*it);
       crtc_controllers_.weak_erase(it);
-      // Release any planes this crtc might own.
-      HardwareDisplayPlaneManager::ResetPlanes(
-          owned_hardware_planes_.find(controller->drm())->second, crtc);
       // Remove entry from |owned_hardware_planes_| iff no other crtcs share it.
       bool found = false;
       for (ScopedVector<CrtcController>::iterator it =
@@ -208,6 +173,14 @@ scoped_ptr<CrtcController> HardwareDisplayController::RemoveCrtc(
       }
       if (!found)
         owned_hardware_planes_.erase(controller->drm());
+
+      controller->RemoveObserver(this);
+      // If a display configuration happens mid page flip we want to make sure
+      // the HDC won't wait for an event from a CRTC that is no longer
+      // associated with it.
+      if (controller->page_flip_pending())
+        OnPageFlipEvent();
+
       return controller.Pass();
     }
   }
@@ -244,4 +217,98 @@ uint64_t HardwareDisplayController::GetTimeOfLastFlip() const {
   return time;
 }
 
+void HardwareDisplayController::OnPageFlipEvent() {
+  TRACE_EVENT0("dri", "HDC::OnPageFlipEvent");
+  // OnPageFlipEvent() needs to handle 2 cases:
+  //  1) Normal page flips in which case:
+  //    a) HasPendingPageFlips() may return false if we're in mirror mode and
+  //       one of the CRTCs hasn't finished page flipping. In this case we want
+  //       to wait for all the CRTCs.
+  //    b) HasPendingPageFlips() returns true in which case all CRTCs are ready
+  //       for the next request. In this case we expect that |requests_| isn't
+  //       empty.
+  //  2) A CRTC was added while it was page flipping. In this case a modeset
+  //     must be performed. Modesetting clears all pending requests, however the
+  //     CRTCs will honor the scheduled page flip. Thus we need to handle page
+  //     flip events with no requests.
+
+  if (HasPendingPageFlips())
+    return;
+
+  if (!requests_.empty())
+    ProcessPageFlipRequest();
+
+  // ProcessPageFlipRequest() consumes a request.
+  if (requests_.empty())
+    return;
+
+  // At this point we still have requests pending, so schedule the next request.
+  bool status = ActualSchedulePageFlip();
+  if (!status) {
+    PageFlipRequest request = requests_.front();
+    requests_.pop_front();
+
+    // Normally the caller would handle the error call, but because we're in a
+    // delayed schedule the initial SchedulePageFlip() already returned true,
+    // thus we need to run the callback.
+    request.callback.Run();
+  }
+}
+
+bool HardwareDisplayController::HasPendingPageFlips() const {
+  for (size_t i = 0; i < crtc_controllers_.size(); ++i)
+    if (crtc_controllers_[i]->page_flip_pending())
+      return true;
+
+  return false;
+}
+
+bool HardwareDisplayController::ActualSchedulePageFlip() {
+  TRACE_EVENT0("dri", "HDC::ActualSchedulePageFlip");
+  DCHECK(!requests_.empty());
+
+  if (is_disabled_) {
+    ProcessPageFlipRequest();
+    return true;
+  }
+
+  OverlayPlaneList pending_planes = requests_.front().planes;
+  std::sort(pending_planes.begin(), pending_planes.end(),
+            [](const OverlayPlane& l, const OverlayPlane& r) {
+    return l.z_order < r.z_order;
+  });
+
+  bool status = true;
+  for (size_t i = 0; i < crtc_controllers_.size(); ++i) {
+    status &= crtc_controllers_[i]->SchedulePageFlip(
+        owned_hardware_planes_.get(crtc_controllers_[i]->drm()),
+        pending_planes);
+  }
+
+  for (const auto& planes : owned_hardware_planes_) {
+    if (!planes.first->plane_manager()->Commit(planes.second)) {
+      status = false;
+    }
+  }
+
+  return status;
+}
+
+void HardwareDisplayController::ProcessPageFlipRequest() {
+  DCHECK(!requests_.empty());
+  PageFlipRequest request = requests_.front();
+  requests_.pop_front();
+
+  current_planes_.swap(request.planes);
+  request.callback.Run();
+}
+
+void HardwareDisplayController::ClearPendingRequests() {
+  while (!requests_.empty()) {
+    PageFlipRequest request = requests_.front();
+    requests_.pop_front();
+    request.callback.Run();
+  }
+}
+
 }  // namespace ui