compositor-drm: Use gbm_bo_import instead of gbm_bo_create_from_egl_surface

This lets us create the gbm bo from the wl_buffer instead of the
EGLImage.  With planar buffer, the EGLImage corresponds to a plane
and not the entire planar buffer.

More importantly, with some YUV formats (packed YUYV and similar) we use
several EGLImages to sample the different components, but KMS only
want one plane in that case.

src/compositor-drm.c

@@ -257,15 +257,11 @@ drm_output_prepare_scanout_surface(struct drm_output *output)
 	    es->geometry.width != output->base.current->width ||
 	    es->geometry.height != output->base.current->height ||
 	    es->transform.enabled ||
-	    es->images[0] == EGL_NO_IMAGE_KHR)
+	    es->buffer == NULL)
 		return -1;
 
-	bo = gbm_bo_create_from_egl_image(c->gbm,
-					  c->base.egl_display,
-					  es->images[0],
-					  es->geometry.width,
-					  es->geometry.height,
-					  GBM_BO_USE_SCANOUT);
+	bo = gbm_bo_import(c->gbm, GBM_BO_IMPORT_WL_BUFFER,
+			   es->buffer, GBM_BO_USE_SCANOUT);
 
 	/* Need to verify output->region contained in surface opaque
 	 * region.  Or maybe just that format doesn't have alpha.
@@ -567,7 +563,7 @@ drm_output_prepare_overlay_surface(struct weston_output *output_base,
 	if (surface_is_primary(ec, es))
 		return -1;
 
-	if (es->num_images != 1 || es->images[0] == EGL_NO_IMAGE_KHR)
+	if (es->buffer == NULL)
 		return -1;
 
 	if (!drm_surface_transform_supported(es))
@@ -590,10 +586,11 @@ drm_output_prepare_overlay_surface(struct weston_output *output_base,
 	if (!found)
 		return -1;
 
-	bo = gbm_bo_create_from_egl_image(c->gbm, c->base.egl_display,
-					  es->images[0], es->geometry.width,
-					  es->geometry.height,
-					  GBM_BO_USE_SCANOUT);
+	bo = gbm_bo_import(c->gbm, GBM_BO_IMPORT_WL_BUFFER,
+			   es->buffer, GBM_BO_USE_SCANOUT);
+	if (!bo)
+		return -1;
+
 	format = gbm_bo_get_format(bo);
 	handle = gbm_bo_get_handle(bo).s32;
 	stride = gbm_bo_get_pitch(bo);