backend/wayland: update output mode after commit is done

Do not update the output mode if the commit failed in one of the
error codepaths.

backend/wayland/output.c

@@ -287,11 +287,6 @@ static bool output_commit(struct wlr_output *wlr_output,
 		return false;
 	}
 
-	if (state->committed & WLR_OUTPUT_STATE_MODE) {
-		wlr_output_update_custom_mode(wlr_output,
-			state->custom_mode.width, state->custom_mode.height, 0);
-	}
-
 	if (state->committed & WLR_OUTPUT_STATE_BUFFER) {
 		struct wp_presentation_feedback *wp_feedback = NULL;
 		if (output->backend->presentation != NULL) {
@@ -360,6 +355,11 @@ static bool output_commit(struct wlr_output *wlr_output,
 
 	wl_display_flush(output->backend->remote_display);
 
+	if (state->committed & WLR_OUTPUT_STATE_MODE) {
+		wlr_output_update_custom_mode(wlr_output,
+			state->custom_mode.width, state->custom_mode.height, 0);
+	}
+
 	return true;
 }