Force GPU switch with CGLSetVirtualScreen only for compositor

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 <stdio.h>
 
 #include <algorithm>
 #include <list>
 #include <map>
 #include <stack>
 #include <string>
 #include <vector>
 
 #include "base/at_exit.h"
 #include "base/atomicops.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
-#if defined(OS_MACOSX)
-#include "base/mac/scoped_cftyperef.h"
-#endif
 #include "base/memory/scoped_ptr.h"
 #include "base/string_number_conversions.h"
 #include "base/stringprintf.h"
 #include "build/build_config.h"
 #define GLES2_GPU_SERVICE 1
 #include "gpu/command_buffer/common/gles2_cmd_format.h"
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
 #include "gpu/command_buffer/common/debug_marker_manager.h"
 #include "gpu/command_buffer/common/id_allocator.h"
 #include "gpu/command_buffer/service/buffer_manager.h"
@@ skipping 20 matching lines @@
 #include "gpu/command_buffer/service/stream_texture_manager.h"
 #include "gpu/command_buffer/service/texture_definition.h"
 #include "gpu/command_buffer/service/texture_manager.h"
 #include "gpu/command_buffer/service/vertex_attrib_manager.h"
 #include "gpu/command_buffer/service/vertex_array_manager.h"
 #include "ui/gl/async_pixel_transfer_delegate.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_image.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_surface.h"
+
 #if defined(OS_MACOSX)
+#include "base/mac/scoped_cftyperef.h"

[Ken Russell (switch to Gerrit), 2013/04/09 00:48:58]

This change is not necessary for this CL; please undo it.

[ccameron, 2013/04/09 17:28:55]

Done.

 #include "ui/surface/io_surface_support_mac.h"
 #endif
 
 // TODO(zmo): we can't include "City.h" due to type def conflicts.
 extern uint64 CityHash64(const char*, size_t);
 
 namespace gpu {
 namespace gles2 {
 
 namespace {
@@ skipping 2491 matching lines @@
 
   DoBindBuffer(GL_ARRAY_BUFFER, 0);
   DoBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
   DoBindFramebuffer(GL_FRAMEBUFFER, 0);
   DoBindRenderbuffer(GL_RENDERBUFFER, 0);
 
   if (feature_info_->workarounds().reverse_point_sprite_coord_origin) {
     glPointParameteri(GL_POINT_SPRITE_COORD_ORIGIN, GL_LOWER_LEFT);
   }
 
+  // Only compositor contexts are known to use only the subset of GL
+  // that can be safely migrated between the iGPU and the dGPU. Mark
+  // those contexts as safe to forcibly transition between the GPUs.
+  // http://crbug.com/180876, http://crbug.com/227228
+  if (!offscreen)
+    context_->SetSafeToForceGpuSwitch();

[Ken Russell (switch to Gerrit), 2013/04/09 00:48:58]

Does this work when virtual contexts are being used? I don't know how the
service side code works in this configuration. Is the same context passed in to
multiple decoder instances?

[ccameron, 2013/04/09 17:28:55]

Good point -- I added support for virtual contexts. This will only work if all
virtualized contexts sharing a context agree about whether or not to allow
force-switching. It so-happens that they do ATM (because we only virtualize
compositor contexts on the Mac), but we may want to make this more stringent.

[Ken Russell (switch to Gerrit), 2013/04/09 17:42:03]

A TODO is needed. It is clear that if we virtualize accelerated 2D canvas's
context in with the compositor's context at some point in the future, things
will break. It's OK to merge the fix in its current form to M27.

+
   // Create a delegate to perform async pixel transfers.
   async_pixel_transfer_delegate_ =
       gfx::AsyncPixelTransferDelegate::Create(context.get());
 
   return true;
 }
 
 void GLES2DecoderImpl::UpdateCapabilities() {
   util_.set_num_compressed_texture_formats(
       validators_->compressed_texture_format.GetValues().size());
@@ skipping 7939 matching lines @@
   return error::kNoError;
 }
 
 // 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 "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu