Implement DRM Native Pixmap using prime buffer

ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc

Index: ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc
diff --git a/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc b/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc
index 3bf453c44b047e88f5f5a5c539ee170417d52e15..284b50b7978ddb611a055bd2b5b61095f268cca5 100644
--- a/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc
+++ b/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc
@@ -8,12 +8,9 @@
 
 #include "base/macros.h"
 #include "ui/gfx/native_pixmap_handle_ozone.h"
+#include "ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.h"
 #include "ui/ozone/public/client_native_pixmap_factory.h"
 
-#if defined(USE_VGEM_MAP)
-#include "ui/ozone/platform/drm/common/client_native_pixmap_vgem.h"
-#endif
-
 namespace ui {
 
 namespace {
@@ -39,14 +36,6 @@ class ClientNativePixmapFactoryGbm : public ClientNativePixmapFactory {
   ~ClientNativePixmapFactoryGbm() override {}
 
   // ClientNativePixmapFactory:
-  void Initialize(base::ScopedFD device_fd) override {
-#if defined(USE_VGEM_MAP)
-    // It's called in IO thread. We rely on clients for thread-safety.
-    // Switching to an IPC message filter ensures thread-safety.
-    DCHECK_LT(vgem_fd_.get(), 0);
-    vgem_fd_ = std::move(device_fd);
-#endif
-  }
   bool IsConfigurationSupported(gfx::BufferFormat format,
                                 gfx::BufferUsage usage) const override {
     switch (usage) {
@@ -58,11 +47,7 @@ class ClientNativePixmapFactoryGbm : public ClientNativePixmapFactory {
                format == gfx::BufferFormat::BGRX_8888;
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE:
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT: {
-#if defined(USE_VGEM_MAP)
-        return vgem_fd_.is_valid() && format == gfx::BufferFormat::BGRA_8888;
-#else
-        return false;
-#endif
+        return format == gfx::BufferFormat::BGRA_8888;

[dshwang, 2016/03/23 15:52:51]

After this CL, Ozone GBM support BGRA_8888, no matter wheter kernel support
dma_buf mmap or not. Only ChromeOS kernel and v4.6+ kernel support it though.

We may need another definition. e.g. USE_DMA_BUF_MMAP
and then return true only if the definition is defined.

spang, what do you think?

[spang, 2016/03/23 16:04:01]

Aren't we only turning on one-copy via flags on vetted boards anyway?

I guess it's not ideal if manually flipping the flag can causes breakage.

If this is merged upstream, there's no reason to have an ifdef around it. We
should compile it in always and detect it at runtime.

[dshwang, 2016/03/23 16:31:11]

Ok, it makes sense.
We add --enable-native-gpu-memory-buffers to specific device supporting it. 
(currently only Broadwell)

As we have runtime flag --enable-native-gpu-memory-buffers, we don't need
additional ifdef. So this CL is lgtm.

Note: ozone-gbm with supported kernel will crash with
--enable-native-gpu-memory-buffers flag.

       }
     }
     NOTREACHED();
@@ -77,15 +62,8 @@ class ClientNativePixmapFactoryGbm : public ClientNativePixmapFactory {
     switch (usage) {
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE:
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT:
-#if defined(USE_VGEM_MAP)
-        // A valid |vgem_fd_| is required to acquire a VGEM bo. |vgem_fd_| is
-        // set before a widget is created.
-        DCHECK_GE(vgem_fd_.get(), 0);
-        return ClientNativePixmapVgem::ImportFromDmabuf(
-            vgem_fd_.get(), scoped_fd.get(), size, handle.stride);
-#endif
-        NOTREACHED();
-        return nullptr;
+        return ClientNativePixmapDmaBuf::ImportFromDmabuf(
+            scoped_fd.get(), size, handle.stride);
       case gfx::BufferUsage::GPU_READ:
       case gfx::BufferUsage::SCANOUT:
         return make_scoped_ptr<ClientNativePixmapGbm>(
@@ -95,11 +73,6 @@ class ClientNativePixmapFactoryGbm : public ClientNativePixmapFactory {
     return nullptr;
   }
 
- private:
-#if defined(USE_VGEM_MAP)
-  base::ScopedFD vgem_fd_;
-#endif
-
   DISALLOW_COPY_AND_ASSIGN(ClientNativePixmapFactoryGbm);
 };