1 files changed, 30 insertions, 4 deletions

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 7d25c42f22db..895741e9cd7d 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -155,6 +155,8 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
 						       state->connectors[i].state);
 		state->connectors[i].ptr = NULL;
 		state->connectors[i].state = NULL;
+		state->connectors[i].old_state = NULL;
+		state->connectors[i].new_state = NULL;
 		drm_connector_put(connector);
 	}
 
@@ -169,6 +171,8 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
 
 		state->crtcs[i].ptr = NULL;
 		state->crtcs[i].state = NULL;
+		state->crtcs[i].old_state = NULL;
+		state->crtcs[i].new_state = NULL;
 	}
 
 	for (i = 0; i < config->num_total_plane; i++) {
@@ -181,6 +185,8 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
 						   state->planes[i].state);
 		state->planes[i].ptr = NULL;
 		state->planes[i].state = NULL;
+		state->planes[i].old_state = NULL;
+		state->planes[i].new_state = NULL;
 	}
 
 	for (i = 0; i < state->num_private_objs; i++) {
@@ -190,6 +196,8 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
 						 state->private_objs[i].state);
 		state->private_objs[i].ptr = NULL;
 		state->private_objs[i].state = NULL;
+		state->private_objs[i].old_state = NULL;
+		state->private_objs[i].new_state = NULL;
 	}
 	state->num_private_objs = 0;
 
@@ -783,6 +791,8 @@ static int drm_atomic_plane_set_property(struct drm_plane *plane,
 		state->src_w = val;
 	} else if (property == config->prop_src_h) {
 		state->src_h = val;
+	} else if (property == plane->alpha_property) {
+		state->alpha = val;
 	} else if (property == plane->rotation_property) {
 		if (!is_power_of_2(val & DRM_MODE_ROTATE_MASK))
 			return -EINVAL;
@@ -848,6 +858,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
 		*val = state->src_w;
 	} else if (property == config->prop_src_h) {
 		*val = state->src_h;
+	} else if (property == plane->alpha_property) {
+		*val = state->alpha;
 	} else if (property == plane->rotation_property) {
 		*val = state->rotation;
 	} else if (property == plane->zpos_property) {
@@ -1421,7 +1433,9 @@ drm_atomic_set_crtc_for_plane(struct drm_plane_state *plane_state,
 {
 	struct drm_plane *plane = plane_state->plane;
 	struct drm_crtc_state *crtc_state;
-
+	/* Nothing to do for same crtc*/
+	if (plane_state->crtc == crtc)
+		return 0;
 	if (plane_state->crtc) {
 		crtc_state = drm_atomic_get_crtc_state(plane_state->state,
 						       plane_state->crtc);
@@ -1492,6 +1506,14 @@ EXPORT_SYMBOL(drm_atomic_set_fb_for_plane);
  * Otherwise, if &drm_plane_state.fence is not set this function we just set it
  * with the received implicit fence. In both cases this function consumes a
  * reference for @fence.
+ *
+ * This way explicit fencing can be used to overrule implicit fencing, which is
+ * important to make explicit fencing use-cases work: One example is using one
+ * buffer for 2 screens with different refresh rates. Implicit fencing will
+ * clamp rendering to the refresh rate of the slower screen, whereas explicit
+ * fence allows 2 independent render and display loops on a single buffer. If a
+ * driver allows obeys both implicit and explicit fences for plane updates, then
+ * it will break all the benefits of explicit fencing.
  */
 void
 drm_atomic_set_fence_for_plane(struct drm_plane_state *plane_state,
@@ -1702,11 +1724,15 @@ int drm_atomic_check_only(struct drm_atomic_state *state)
 		}
 	}
 
-	if (config->funcs->atomic_check)
+	if (config->funcs->atomic_check) {
 		ret = config->funcs->atomic_check(state->dev, state);
 
-	if (ret)
-		return ret;
+		if (ret) {
+			DRM_DEBUG_ATOMIC("atomic driver check for %p failed: %d\n",
+					 state, ret);
+			return ret;
+		}
+	}
 
 	if (!state->allow_modeset) {
 		for_each_new_crtc_in_state(state, crtc, crtc_state, i) {