ozone: Implement zero/one-copy texture for Ozone GBM.

ui/ozone/platform/drm/common/client_native_pixmap_factory_gbm.cc

 // Copyright 2015 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 "ui/ozone/platform/drm/common/client_native_pixmap_factory_gbm.h"
 
+#include <fcntl.h>
+
 #include "base/file_descriptor_posix.h"
+#include "ui/ozone/platform/drm/gpu/client_native_pixmap_vgem.h"
 #include "ui/ozone/public/client_native_pixmap_factory.h"
 
 namespace ui {
 
 namespace {
 
 class ClientNativePixmapFactoryGbm : public ClientNativePixmapFactory {
  public:
-  ClientNativePixmapFactoryGbm() {}
+  ClientNativePixmapFactoryGbm() {
+#if defined(OZONE_USE_VGEM_MAP)
+    // TODO(dshwang): remove ad-hoc file open. crrev.com/1248713002
+    static const char kVgemPath[] = "/dev/dri/renderD129";
+    int vgem_fd = open(kVgemPath, O_RDWR | O_CLOEXEC);
+    if (vgem_fd < 0) {
+      PLOG(ERROR) << "Failed to open: " << kVgemPath;
+      return;
+    }
+    vgem_fd_.reset(vgem_fd);
+#endif
+  }
   ~ClientNativePixmapFactoryGbm() override {}
 
   // ClientNativePixmapFactory:
   std::vector<Configuration> GetSupportedConfigurations() const override {
     const Configuration kConfiguratioins[] = {
         {gfx::BufferFormat::BGRA_8888, gfx::BufferUsage::SCANOUT},
         {gfx::BufferFormat::RGBX_8888, gfx::BufferUsage::SCANOUT}};
     std::vector<Configuration> configurations(
         kConfiguratioins, kConfiguratioins + arraysize(kConfiguratioins));
+#if defined(OZONE_USE_VGEM_MAP)
+    // Map requires VGEM supports.
+    if (vgem_fd_.get() >= 0) {

[reveman, 2015/08/06 12:08:35]

why would this fail?

[dshwang, 2015/08/06 13:59:17]

upstream linux doens't have vgem device. In addition, ctor opens
"/dev/dri/renderD129" by itself. without --no-sandbox, it's failed.

In addition, OZONE_USE_VGEM_MAP checks VGEM map is supported, not VGEM is
enabled.
In cros linux 3.14, VGEM is enabled on all platform. However, VGEM map is
supported in only Intel platform.

+      configurations.push_back(
+          {gfx::BufferFormat::BGRA_8888, gfx::BufferUsage::MAP});
+    }
+#endif
     return configurations;
   }
   scoped_ptr<ClientNativePixmap> ImportFromHandle(
       const gfx::NativePixmapHandle& handle,
       const gfx::Size& size,
       gfx::BufferFormat format,
       gfx::BufferUsage usage) override {
-    NOTIMPLEMENTED();
-    return nullptr;
+    DCHECK(usage == gfx::BufferUsage::MAP);

[reveman, 2015/08/06 12:08:35]

why do we care what the usage is?

[dshwang, 2015/08/06 13:59:17]

Either GpuMemoryBufferImplOzoneNativePixmap or ClientNativePixmapFactory or
ClientNativePixmapVgem controls logic along with usage. I decided
GpuMemoryBufferImplOzoneNativePixmap to control, but you seem to want
ClientNativePixmapVgem to handle usage.

In scanout case, it's overkill to creat vgem bo, because it's never used. It's
why I didn't create pixmap explicitly in GpuMemoryBufferImplOzoneNativePixmap.
In addition, upstream linux must be able to use scanout buffer without vgem
device.

Let me make ClientNativePixmapFactory control it.

+    if (vgem_fd_.get() < 0)
+      return nullptr;
+    scoped_ptr<ClientNativePixmapVgem> pixmap(new ClientNativePixmapVgem(
+        handle, base::FileDescriptor(vgem_fd_.get(), false), size, format));
+    if (!pixmap->Initialize())

[reveman, 2015/08/06 12:08:35]

can you move the work done in Initialize out here and use the ctor at the time
we know this can't fail.

[dshwang, 2015/08/06 13:59:17]

do you mean that this function call directly "drmPrimeFDToHandle(vgem_fd_.fd,
dma_buf_.get(), &vgem_bo_handle_)"?
It's vgem detail. ClientNativePixmapFactoryGbm should not know it.
I replace Initialize() with Create()

+      return nullptr;
+
+    return pixmap.Pass();
   }
 
  private:
+  base::ScopedFD vgem_fd_;
+
   DISALLOW_COPY_AND_ASSIGN(ClientNativePixmapFactoryGbm);
 };
 
 }  // namespace
 
 ClientNativePixmapFactory* CreateClientNativePixmapFactoryGbm() {
   return new ClientNativePixmapFactoryGbm();
 }
 
 }  // namespace ui