ozone: Wait on EGLFence before committing buffers. Avoid using GL.

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

Index: ui/ozone/platform/drm/gpu/gbm_surfaceless.cc
diff --git a/ui/ozone/platform/drm/gpu/gbm_surfaceless.cc b/ui/ozone/platform/drm/gpu/gbm_surfaceless.cc
index b436a7b2871433ad8d3bce905e3b7fc7252c5811..722de976b72684a39248b0e149258c3f0d5b33b2 100644
--- a/ui/ozone/platform/drm/gpu/gbm_surfaceless.cc
+++ b/ui/ozone/platform/drm/gpu/gbm_surfaceless.cc
@@ -37,8 +37,6 @@ GbmSurfaceless::GbmSurfaceless(GbmSurfaceFactory* surface_factory,
       widget_(widget),
       has_implicit_external_sync_(
           HasEGLExtension("EGL_ARM_implicit_external_sync")),
-      has_image_flush_external_(
-          HasEGLExtension("EGL_EXT_image_flush_external")),

[marcheu, 2017/05/02 21:10:14]

hmm, note that we need this to happen somehow... But right now it is also on the
wrong context which I guess has no effect. Should the eglimageflush be moved
outside of ozone?

[Daniele Castagna, 2017/05/02 21:23:31]

This happens per image. Look at GLImageNativePixmap::Flush, it gets called from
unsubmitted_frames_.back()->Flush(); in GbmSurfaceless::SwapBuffersAsync just
before we insert and wait for the fence.
The boolean here was just to make sure we'd insert the fence if
eglImageFlushExternalEXT was used. Now we always insert the fence so we don't
need the check at this level.

eglImageFlushExternalEXT shouldn't use the GL context, so it should work.

       weak_factory_(this) {
   surface_factory_->RegisterSurface(window_->widget(), this);
   unsubmitted_frames_.push_back(base::MakeUnique<PendingFrame>());
@@ -105,7 +103,6 @@ void GbmSurfaceless::SwapBuffersAsync(const SwapCompletionCallback& callback) {
     return;
   }
 
-  glFlush();
   unsubmitted_frames_.back()->Flush();
 
   SwapCompletionCallback surface_swap_callback = base::Bind(
@@ -117,31 +114,25 @@ void GbmSurfaceless::SwapBuffersAsync(const SwapCompletionCallback& callback) {
 
   // TODO: the following should be replaced by a per surface flush as it gets
   // implemented in GL drivers.
-  if (has_implicit_external_sync_ || has_image_flush_external_) {
-    EGLSyncKHR fence = InsertFence(has_implicit_external_sync_);
-    if (!fence) {
-      callback.Run(gfx::SwapResult::SWAP_FAILED);
-      return;
-    }
-
-    base::Closure fence_wait_task =
-        base::Bind(&WaitForFence, GetDisplay(), fence);
+  EGLSyncKHR fence = InsertFence(has_implicit_external_sync_);
+  if (!fence) {
+    callback.Run(gfx::SwapResult::SWAP_FAILED);
+    return;
+  }
 
-    base::Closure fence_retired_callback =
-        base::Bind(&GbmSurfaceless::FenceRetired, weak_factory_.GetWeakPtr(),
-                   fence, frame);
+  base::Closure fence_wait_task =
+      base::Bind(&WaitForFence, GetDisplay(), fence);
 
-    base::PostTaskWithTraitsAndReply(
-        FROM_HERE, base::TaskTraits()
-                       .WithShutdownBehavior(
-                           base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN)
-                       .MayBlock(),
-        fence_wait_task, fence_retired_callback);
-    return;  // Defer frame submission until fence signals.
-  }
+  base::Closure fence_retired_callback = base::Bind(
+      &GbmSurfaceless::FenceRetired, weak_factory_.GetWeakPtr(), fence, frame);
 
-  frame->ready = true;
-  SubmitFrame();
+  base::PostTaskWithTraitsAndReply(
+      FROM_HERE,
+      base::TaskTraits()
+          .WithShutdownBehavior(
+              base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN)
+          .MayBlock(),
+      fence_wait_task, fence_retired_callback);
 }
 
 void GbmSurfaceless::PostSubBufferAsync(
@@ -213,9 +204,6 @@ void GbmSurfaceless::SubmitFrame() {
       return;
     }
 
-    if (IsUniversalDisplayLinkDevice())
-      glFinish();
-
     window_->SchedulePageFlip(planes_, frame->callback);
     planes_.clear();
   }
@@ -247,8 +235,4 @@ void GbmSurfaceless::SwapCompleted(const SwapCompletionCallback& callback,
   SubmitFrame();
 }
 
-bool GbmSurfaceless::IsUniversalDisplayLinkDevice() {
-  return planes_.empty() ? false : planes_[0].buffer->RequiresGlFinish();
-}
-
 }  // namespace ui