2 files changed, 5 insertions, 3 deletions

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 9c528bbcd8d2..28aa87510551 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -723,7 +723,7 @@ crtc_set_mode(struct drm_device *dev, struct drm_atomic_state *old_state)
 
                 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 @@ crtc_set_mode(struct drm_device *dev, struct drm_atomic_state *old_state)
                  * 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 c250a22b39ab..92d5135b55d2 100644
--- a/include/drm/drm_crtc_helper.h
+++ b/include/drm/drm_crtc_helper.h
@@ -89,6 +89,7 @@ struct drm_crtc_helper_funcs {
         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 @@ struct drm_crtc_helper_funcs {
  * @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)