ozone: Import multi-planar GBMs.

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

Index: ui/ozone/platform/drm/gpu/gbm_buffer.cc
diff --git a/ui/ozone/platform/drm/gpu/gbm_buffer.cc b/ui/ozone/platform/drm/gpu/gbm_buffer.cc
index 5d4643411a6e5f0f9de70d737a2c51c0dc209e44..aab2bf06f8bcded81ea9fb909cd297d2b7715978 100644
--- a/ui/ozone/platform/drm/gpu/gbm_buffer.cc
+++ b/ui/ozone/platform/drm/gpu/gbm_buffer.cc
@@ -184,23 +184,27 @@ scoped_refptr<GbmBuffer> GbmBuffer::CreateBufferFromFds(
   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";