drm: Perform a full mode set when the pixel format changed

Test whether the pixel format changes in the mode set handler, and
perform a full mode set instead of a mode set base if it does.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_crtc_helper.c

@@ -648,6 +648,9 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
 		} else if (set->fb->bits_per_pixel !=
 			   set->crtc->fb->bits_per_pixel) {
 			mode_changed = true;
+		} else if (set->fb->pixel_format !=
+			   set->crtc->fb->pixel_format) {
+			mode_changed = true;
 		} else
 			fb_changed = true;
 	}