[PATCH 1/3] drm/atomic: only add states of active or transient active colorops

[Melissa Wen <mwen@igalia.com>]

Only consider affected colorop states those that are part of an active
color pipeline or a pipeline that is about to be activated or
deactivated in the same atomic commit, i.e., colorop is in the chain of
old/new plane color pipeline property. To cover color_pipeline
deactivation, remove the condition for plane_state->color_pipeline.

Signed-off-by: Melissa Wen <mwen@igalia.com>
---
 drivers/gpu/drm/drm_atomic.c | 67 +++++++++++++++++++++++++++++++-----
 1 file changed, 58 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 170de30c28ae..4fb3a23e862a 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -812,6 +812,59 @@ static int drm_atomic_plane_check(const struct drm_plane_state *old_plane_state,
 	return 0;
 }
 
+/*
+ * This function walks old and new plane state color pipelines and adds all
+ * colorops in use by @plane to the atomic configuration @state. This is useful
+ * when an atomic commit needs to check all currently enabled or about to be
+ * enabled colorop on @plane, e.g. when changing the mode. This also avoids
+ * including colorop states that are not part of the atomic state.
+ *
+ * Returns:
+ * 0 on success or can fail with -EDEADLK or -ENOMEM. When the error is EDEADLK
+ * then the w/w mutex code has detected a deadlock and the entire atomic
+ * sequence must be restarted. All other errors are fatal.
+ */
+static int
+drm_atomic_add_pipeline_colorops(struct drm_atomic_commit *state,
+				 struct drm_plane *plane)
+{
+	struct drm_colorop *colorop;
+	struct drm_colorop_state *colorop_state;
+	struct drm_plane_state *new_plane_state, *old_plane_state;
+
+	new_plane_state = drm_atomic_get_new_plane_state(state, plane);
+	old_plane_state = drm_atomic_get_old_plane_state(state, plane);
+
+	if (WARN_ON(!new_plane_state || !old_plane_state))
+		return -EINVAL;
+
+	drm_dbg_atomic(plane->dev,
+		       "Adding old+new pipeline colorops for [PLANE:%d:%s]\n",
+		       plane->base.id, plane->name);
+
+	for (colorop = new_plane_state->color_pipeline;
+	     colorop;
+	     colorop = colorop->next) {
+		colorop_state = drm_atomic_get_colorop_state(state, colorop);
+		if (IS_ERR(colorop_state))
+			return PTR_ERR(colorop_state);
+	}
+
+	/* Same color pipeline as new; no point walking old. */
+	if (new_plane_state->color_pipeline == old_plane_state->color_pipeline)
+		return 0;
+
+	for (colorop = old_plane_state->color_pipeline;
+	     colorop;
+	     colorop = colorop->next) {
+		colorop_state = drm_atomic_get_colorop_state(state, colorop);
+		if (IS_ERR(colorop_state))
+			return PTR_ERR(colorop_state);
+	}
+
+	return 0;
+}
+
 static void drm_atomic_colorop_print_state(struct drm_printer *p,
 					   const struct drm_colorop_state *state)
 {
@@ -1591,11 +1644,9 @@ drm_atomic_add_affected_planes(struct drm_atomic_commit *state,
 		if (IS_ERR(plane_state))
 			return PTR_ERR(plane_state);
 
-		if (plane_state->color_pipeline) {
-			ret = drm_atomic_add_affected_colorops(state, plane);
-			if (ret)
-				return ret;
-		}
+		ret = drm_atomic_add_pipeline_colorops(state, plane);
+		if (ret)
+			return ret;
 	}
 	return 0;
 }
@@ -1607,10 +1658,8 @@ EXPORT_SYMBOL(drm_atomic_add_affected_planes);
  * @plane: DRM plane
  *
  * This function walks the current configuration and adds all colorops
- * currently used by @plane to the atomic configuration @state. This is useful
- * when an atomic commit also needs to check all currently enabled colorop on
- * @plane, e.g. when changing the mode. It's also useful when re-enabling a plane
- * to avoid special code to force-enable all colorops.
+ * currently used by @plane to the atomic configuration @state. It's useful
+ * when re-enabling a plane to avoid special code to force-enable all colorops.
  *
  * Since acquiring a colorop state will always also acquire the w/w mutex of the
  * current plane for that colorop (if there is any) adding all the colorop states for
-- 
2.53.0