diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 9c528bb..28aa875 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -723,7 +723,7 @@
 
 		funcs = crtc->helper_private;
 
-		if (crtc->state->enable) {
+		if (crtc->state->enable && funcs->mode_set_nofb) {
 			DRM_DEBUG_ATOMIC("modeset on [CRTC:%d]\n",
 					 crtc->base.id);
 
@@ -759,7 +759,8 @@
 		 * Each encoder has at most one connector (since we always steal
 		 * it away), so we won't call call mode_set hooks twice.
 		 */
-		funcs->mode_set(encoder, mode, adjusted_mode);
+		if (funcs->mode_set)
+			funcs->mode_set(encoder, mode, adjusted_mode);
 
 		if (encoder->bridge && encoder->bridge->funcs->mode_set)
 			encoder->bridge->funcs->mode_set(encoder->bridge,
diff --git a/include/drm/drm_crtc_helper.h b/include/drm/drm_crtc_helper.h
index c250a22..92d5135 100644
--- a/include/drm/drm_crtc_helper.h
+++ b/include/drm/drm_crtc_helper.h
@@ -89,6 +89,7 @@
 	int (*mode_set)(struct drm_crtc *crtc, struct drm_display_mode *mode,
 			struct drm_display_mode *adjusted_mode, int x, int y,
 			struct drm_framebuffer *old_fb);
+	/* Actually set the mode for atomic helpers, optional */
 	void (*mode_set_nofb)(struct drm_crtc *crtc);
 
 	/* Move the crtc on the current fb to the given position *optional* */
@@ -119,7 +120,7 @@
  * @mode_fixup: try to fixup proposed mode for this connector
  * @prepare: part of the disable sequence, called before the CRTC modeset
  * @commit: called after the CRTC modeset
- * @mode_set: set this mode
+ * @mode_set: set this mode, optional for atomic helpers
  * @get_crtc: return CRTC that the encoder is currently attached to
  * @detect: connection status detection
  * @disable: disable encoder when not in use (overrides DPMS off)