sna/dri: Assert that the old scanout is clear before overwriting

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/sna/sna_dri.c b/src/sna/sna_dri.c
index 89e3410d..732143a7 100644
--- a/src/sna/sna_dri.c
+++ b/src/sna/sna_dri.c
@@ -1097,6 +1097,7 @@ sna_dri_page_flip(struct sna *sna, struct sna_dri_frame_event *info)
 	assert(sna_pixmap_get_buffer(sna->front) == info->front);
 	assert(get_drawable_pixmap(info->draw)->drawable.height * bo->pitch <= kgem_bo_size(bo));
 	assert(info->scanout[0].bo);
+	assert(info->scanout[1].bo == NULL);
 
 	info->count = sna_page_flip(sna, bo, info, info->pipe);
 	if (!info->count)