diff --git a/types/wlr_output.c b/types/wlr_output.c
index ce05f97b9..7989f03d2 100644
--- a/types/wlr_output.c
+++ b/types/wlr_output.c
@@ -267,6 +267,15 @@ void wlr_output_set_subpixel(struct wlr_output *output,
 	wlr_output_schedule_done(output);
 }
 
+void wlr_output_set_format(struct wlr_output *output,
+		enum wl_shm_format format) {
+	if (output->format == format) {
+		return;
+	}
+
+	output->format = format;
+}
+
 void wlr_output_set_description(struct wlr_output *output, const char *desc) {
 	if (output->description != NULL && desc != NULL &&
 			strcmp(output->description, desc) == 0) {