drm/i915: Plumb the entire atomic state into intel_color_check()

Bunch of stuff in intel_color_check() needs to look at both the
old and new crtc states. Currently we do that by digging the
full atomic state via the crtc_state->state pointer. That thing
is a total footgun if I ever saw one, as it's only valid during
specific parts of the atomic flow. A lot of people have been
bitten by this thing in the past when trying to use it after
it's no longer valid.

Take a small step towards elimination of the footgun by not
using it in the inte_color_check(). Instead we plumb in the
entire atomic state all the way from the top.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240523182818.15382-2-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_color.h

@@ -8,6 +8,7 @@
 
 #include <linux/types.h>
 
+struct intel_atomic_state;
 struct intel_crtc_state;
 struct intel_crtc;
 struct drm_i915_private;
@@ -16,7 +17,8 @@ struct drm_property_blob;
 void intel_color_init_hooks(struct drm_i915_private *i915);
 int intel_color_init(struct drm_i915_private *i915);
 void intel_color_crtc_init(struct intel_crtc *crtc);
-int intel_color_check(struct intel_crtc_state *crtc_state);
+int intel_color_check(struct intel_atomic_state *state,
+		      struct intel_crtc *crtc);
 void intel_color_prepare_commit(struct intel_crtc_state *crtc_state);
 void intel_color_cleanup_commit(struct intel_crtc_state *crtc_state);
 bool intel_color_uses_dsb(const struct intel_crtc_state *crtc_state);

drivers/gpu/drm/i915/display/intel_display.c

@@ -4255,7 +4255,7 @@ static int intel_crtc_atomic_check(struct intel_atomic_state *state,
 		crtc_state->uapi.color_mgmt_changed = true;
 
 	if (intel_crtc_needs_color_update(crtc_state)) {
-		ret = intel_color_check(crtc_state);
+		ret = intel_color_check(state, crtc);
 		if (ret)
 			return ret;
 	}