gpu: Empty swaps for surfaceless output surfaces.

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ skipping 3574 matching lines @@
     // Clear the backbuffer.
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
 
     // Restore alpha clear value if we changed it.
     if (clear_alpha) {
       glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
     }
   }
 
   supports_post_sub_buffer_ = surface->SupportsPostSubBuffer();
-  if (workarounds()
-          .disable_post_sub_buffers_for_onscreen_surfaces &&
-      !surface->IsOffscreen())
-    supports_post_sub_buffer_ = false;
 
   supports_swap_buffers_with_bounds_ = surface->SupportsSwapBuffersWithBounds();
 
   supports_commit_overlay_planes_ = surface->SupportsCommitOverlayPlanes();
 
   supports_async_swap_ = surface->SupportsAsyncSwap();
 
   supports_dc_layers_ = !offscreen && surface->SupportsDCLayers();
 
   if (workarounds().reverse_point_sprite_coord_origin) {
@@ skipping 200 matching lines @@
   caps.gpu_rasterization =
       group_->gpu_feature_info()
           .status_values[GPU_FEATURE_TYPE_GPU_RASTERIZATION] ==
       kGpuFeatureStatusEnabled;
   caps.disable_webgl_rgb_multisampling_usage =
       workarounds().disable_webgl_rgb_multisampling_usage;
   caps.software_to_accelerated_canvas_upgrade =
       !workarounds().disable_software_to_accelerated_canvas_upgrade;
   caps.emulate_rgb_buffer_with_rgba =
       workarounds().disable_gl_rgb_format;
+  if (workarounds().disable_post_sub_buffers_for_onscreen_surfaces &&
+      !surface_->IsOffscreen()) {

[jbauman, 2017/04/20 21:30:06]

We need a different workaround for this. Otherwise we'll enable empty partial
swap on mesa and virtualbox, where it's probably buggy.

[reveman, 2017/04/20 22:11:40]

Unlikely that we do empty swaps without overlays but still makes sense to have a
separate workaround to be safe. Done.

+    caps.disable_non_empty_post_sub_buffers = true;
+  }
 
   return caps;
 }
 
 void GLES2DecoderImpl::UpdateCapabilities() {
   util_.set_num_compressed_texture_formats(
       validators_->compressed_texture_format.GetValues().size());
   util_.set_num_shader_binary_formats(
       validators_->shader_binary_format.GetValues().size());
 }
@@ skipping 15748 matching lines @@
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "base/macros.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu