drm/drm_plane: track color mgmt changes per plane

We will add color mgmt properties to DRM planes in the next patches and
we want to track when one of this properties change to define atomic
commit behaviors. Using a similar approach from CRTC color props, we set
a color_mgmt_changed boolean whenever a plane color prop changes.
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Melissa Wen <mwen@igalia.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/drm_atomic.c

@@ -733,6 +733,7 @@ static void drm_atomic_plane_print_state(struct drm_printer *p,
 		   drm_get_color_encoding_name(state->color_encoding));
 	drm_printf(p, "\tcolor-range=%s\n",
 		   drm_get_color_range_name(state->color_range));
+	drm_printf(p, "\tcolor_mgmt_changed=%d\n", state->color_mgmt_changed);
 
 	if (plane->funcs->atomic_print_state)
 		plane->funcs->atomic_print_state(p, state);

drivers/gpu/drm/drm_atomic_state_helper.c

@@ -352,6 +352,7 @@ void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,
 	state->fence = NULL;
 	state->commit = NULL;
 	state->fb_damage_clips = NULL;
+	state->color_mgmt_changed = false;
 }
 EXPORT_SYMBOL(__drm_atomic_helper_plane_duplicate_state);
 

include/drm/drm_plane.h

@@ -251,6 +251,13 @@ struct drm_plane_state {
 
 	/** @state: backpointer to global drm_atomic_state */
 	struct drm_atomic_state *state;
+
+	/**
+	 * @color_mgmt_changed: Color management properties have changed. Used
+	 * by the atomic helpers and drivers to steer the atomic commit control
+	 * flow.
+	 */
+	bool color_mgmt_changed : 1;
 };
 
 static inline struct drm_rect