ozone: Import multi-planar GBMs.

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 166 matching lines @@
     uint32_t format,
     const gfx::Size& size,
     std::vector<base::ScopedFD>&& fds,
     const std::vector<gfx::NativePixmapPlane>& planes) {
   TRACE_EVENT2("drm", "GbmBuffer::CreateBufferFromFD", "device",
                gbm->device_path().value(), "size", size.ToString());
   DCHECK_LE(fds.size(), planes.size());
   DCHECK_EQ(planes[0].offset, 0);
 
   // Try to use scanout if supported.
-  bool try_scanout =
-      gbm_device_is_format_supported(
-          gbm->device(), format, GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING) &&
-      (planes.size() == 1);
+  bool try_scanout = gbm_device_is_format_supported(
+      gbm->device(), format, GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING);
 
   gbm_bo* bo = nullptr;
   if (try_scanout) {
-    struct gbm_import_fd_data fd_data;
-    fd_data.fd = fds[0].get();
+    struct gbm_import_fd_planar_data fd_data {};

[reveman, 2017/03/21 03:36:09]

nit: leave uninitialized so asan can detect if gbm_bo_import is using part of
this struct that is not supposed to be used

[Daniele Castagna, 2017/03/21 03:47:09]

Done.

     fd_data.width = size.width();
     fd_data.height = size.height();
-    fd_data.stride = planes[0].stride;
     fd_data.format = format;
 
+    DCHECK_LT(planes.size(), 3u);
+    for (size_t i = 0; i < planes.size(); ++i) {
+      fd_data.fds[i] = fds[i < fds.size() ? i : 0].get();

[reveman, 2017/03/21 03:36:09]

what if fds.size() is 2 and planes.size() is 3. do we want fd_data.fds[1] to be
fds[1] or fds[0]? should this function fail if fds.size() is not 1 or
planes.size()?

[Daniele Castagna, 2017/03/21 03:47:09]

This is consistent with what we do for
eglCreateImageKHR:GLImageNativePixmap::Initialize

If we want to change it, I'm happy to follow up with another CL that changes the
behavior in both places.
As discussed offline. If we want to enforce if the number of fds to be 1 or
fds.size(), we should filter other configurations in exo.

I'm starting another thread about the relation between fds and planes because,
as it's clear from comments on this CL, it's not clear with the current state of
things.

+      fd_data.strides[i] = planes[i].stride;
+      fd_data.offsets[i] = planes[i].offset;
+      fd_data.format_modifiers[i] = planes[i].modifier;
+    }
+
     // The fd passed to gbm_bo_import is not ref-counted and need to be
     // kept open for the lifetime of the buffer.
-    bo = gbm_bo_import(gbm->device(), GBM_BO_IMPORT_FD, &fd_data,
+    bo = gbm_bo_import(gbm->device(), GBM_BO_IMPORT_FD_PLANAR, &fd_data,
                        GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING);
     if (!bo) {
       LOG(ERROR) << "nullptr returned from gbm_bo_import";
       return nullptr;
     }
   }
 
   uint32_t flags = GBM_BO_USE_RENDERING;
   if (try_scanout)
     flags |= GBM_BO_USE_SCANOUT;
@@ skipping 116 matching lines @@
   DCHECK(!processing_callback_.is_null());
   if (!processing_callback_.Run(this, processed_pixmap_)) {
     LOG(ERROR) << "Failed processing NativePixmap";
     return nullptr;
   }
 
   return processed_pixmap_->buffer();
 }
 
 }  // namespace ui