ozone: Implement support for CreateGpuMemoryBufferFromHandle for OzoneNativePixmap backed GMBs.

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

 // Copyright 2014 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/gpu/gbm_buffer.h"
 
 #include <drm.h>
 #include <fcntl.h>
 #include <gbm.h>
 #include <xf86drm.h>
@@ skipping 55 matching lines @@
   if (!bo)
     return nullptr;
 
   scoped_refptr<GbmBuffer> buffer(new GbmBuffer(gbm, bo, usage));
   if (use_scanout && !buffer->GetFramebufferId())
     return nullptr;
 
   return buffer;
 }
 
-GbmPixmap::GbmPixmap(const scoped_refptr<GbmBuffer>& buffer,
-                     GbmSurfaceFactory* surface_manager)
-    : buffer_(buffer), surface_manager_(surface_manager) {}
+GbmPixmap::GbmPixmap(GbmSurfaceFactory* surface_manager)
+    : surface_manager_(surface_manager) {}
 
-bool GbmPixmap::Initialize() {
+void GbmPixmap::Initialize(int dma_buf, int dma_buf_pitch) {
+  dma_buf_ = dma_buf;
+  dma_buf_pitch_ = dma_buf_pitch;
+}
+
+bool GbmPixmap::InitializeFromBuffer(const scoped_refptr<GbmBuffer>& buffer) {
   // We want to use the GBM API because it's going to call into libdrm
   // which might do some optimizations on buffer allocation,
   // especially when sharing buffers via DMABUF.
-  dma_buf_ = gbm_bo_get_fd(buffer_->bo());
-  if (dma_buf_ < 0) {
+  int dma_buf = gbm_bo_get_fd(buffer->bo());
+  if (dma_buf < 0) {
     PLOG(ERROR) << "Failed to export buffer to dma_buf";
     return false;
   }
+  Initialize(dma_buf, gbm_bo_get_stride(buffer->bo()));
+  buffer_ = buffer;
   return true;
 }
 
 void GbmPixmap::SetScalingCallback(const ScalingCallback& scaling_callback) {
   scaling_callback_ = scaling_callback;
 }
 
 scoped_refptr<NativePixmap> GbmPixmap::GetScaledPixmap(gfx::Size new_size) {
   return scaling_callback_.Run(new_size);
 }
 
 gfx::NativePixmapHandle GbmPixmap::ExportHandle() {
   gfx::NativePixmapHandle handle;
 
   int dmabuf_fd = HANDLE_EINTR(dup(dma_buf_));
   if (dmabuf_fd < 0) {
     PLOG(ERROR) << "dup";
     return handle;
   }
 
   handle.fd = base::FileDescriptor(dmabuf_fd, true /* auto_close */);
-  handle.stride = gbm_bo_get_stride(buffer_->bo());
+  handle.stride = dma_buf_pitch_;
   return handle;
 }
 
 GbmPixmap::~GbmPixmap() {
   if (dma_buf_ > 0)
     close(dma_buf_);
 }
 
 void* GbmPixmap::GetEGLClientBuffer() {
   return nullptr;
 }
 
 int GbmPixmap::GetDmaBufFd() {
   return dma_buf_;
 }
 
 int GbmPixmap::GetDmaBufPitch() {
-  return gbm_bo_get_stride(buffer_->bo());
+  return dma_buf_pitch_;
 }
 
 bool GbmPixmap::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                                      int plane_z_order,
                                      gfx::OverlayTransform plane_transform,
                                      const gfx::Rect& display_bounds,
                                      const gfx::RectF& crop_rect) {
-  DCHECK(buffer_->GetUsage() == gfx::BufferUsage::SCANOUT);
   gfx::Size required_size;
   if (plane_z_order &&
       ShouldApplyScaling(display_bounds, crop_rect, &required_size)) {
     scoped_refptr<NativePixmap> scaled_pixmap = GetScaledPixmap(required_size);
     if (scaled_pixmap) {
       return scaled_pixmap->ScheduleOverlayPlane(
           widget, plane_z_order, plane_transform, display_bounds, crop_rect);
     } else {
       return false;
     }
   }
 
+  if (!buffer_) {

[piman, 2015/10/08 23:24:36]

I assume eventually we'll want to support this for imported handles too, right?
Do we have an idea what we need to do to make it possible?

[reveman, 2015/10/09 12:47:02]

I haven't looked at this much in detail but it seems like we need to implement
gbm_bo_import(GBM_BO_IMPORT_FD) in minigbm for this to work properly. Created a
bug and linked to it here in a TODO.

+    PLOG(ERROR) << "ScheduleOverlayPlane requires a buffer.";
+    return false;
+  }
+
+  DCHECK(buffer_->GetUsage() == gfx::BufferUsage::SCANOUT);
   surface_manager_->GetSurface(widget)->QueueOverlayPlane(OverlayPlane(
       buffer_, plane_z_order, plane_transform, display_bounds, crop_rect));
   return true;
 }
 
 bool GbmPixmap::ShouldApplyScaling(const gfx::Rect& display_bounds,
                                    const gfx::RectF& crop_rect,
                                    gfx::Size* required_size) {
   if (crop_rect.width() == 0 || crop_rect.height() == 0) {
     PLOG(ERROR) << "ShouldApplyScaling passed zero scaling target.";
     return false;
   }
 
+  if (!buffer_) {
+    PLOG(ERROR) << "ShouldApplyScaling requires a buffer.";
+    return false;
+  }
+
   gfx::Size pixmap_size = buffer_->GetSize();
   // If the required size is not integer-sized, round it to the next integer.
   *required_size = gfx::ToCeiledSize(
       gfx::SizeF(display_bounds.width() / crop_rect.width(),
                  display_bounds.height() / crop_rect.height()));
   return pixmap_size != *required_size;
 }
 
 }  // namespace ui