compositor-drm: avoid scissor in assign_planes

Support for scissor not implemented yet on cursor overlay or for direct
scanout. Overlays OTOH use the boundingbox to compute their coordinates,
so that should probably work.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>
Tested-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>
Reviewed-By: Derek Foreman <derekf@osg.samsung.com>

src/compositor-drm.c

@@ -481,6 +481,9 @@ drm_output_prepare_scanout_view(struct drm_output *output,
 	    ev->transform.enabled)
 		return NULL;
 
+	if (ev->geometry.scissor_enabled)
+		return NULL;
+
 	bo = gbm_bo_import(c->gbm, GBM_BO_IMPORT_WL_BUFFER,
 			   buffer->resource, GBM_BO_USE_SCANOUT);
 
@@ -1000,6 +1003,8 @@ drm_output_prepare_cursor_view(struct drm_output *output,
 		return NULL;
 	if (c->cursors_are_broken)
 		return NULL;
+	if (ev->geometry.scissor_enabled)
+		return NULL;
 	if (ev->surface->buffer_ref.buffer == NULL ||
 	    !wl_shm_buffer_get(ev->surface->buffer_ref.buffer->resource) ||
 	    ev->surface->width > 64 || ev->surface->height > 64)