drm/i915: avoid full modeset when changing the color range properties

Automatic color range selection was added in

commit 55bc60db
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Thu Jan 17 16:31:29 2013 +0200

    drm/i915: Add "Automatic" mode for the "Broadcast RGB" property

but that removed the check to avoid a full modeset if the value is
unchanged. Unfortunately X sets all properties with their current
value at start-up, resulting in some ugly flickering which shouldn't
be there.

v2: Change old_range from bool to uint32_t, spotted by Ville.

v3: Actually git add everything ;-)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -2428,6 +2428,9 @@ intel_dp_set_property(struct drm_connector *connector,
 	}
 
 	if (property == dev_priv->broadcast_rgb_property) {
+		bool old_auto = intel_dp->color_range_auto;
+		uint32_t old_range = intel_dp->color_range;
+
 		switch (val) {
 		case INTEL_BROADCAST_RGB_AUTO:
 			intel_dp->color_range_auto = true;
@@ -2443,6 +2446,11 @@ intel_dp_set_property(struct drm_connector *connector,
 		default:
 			return -EINVAL;
 		}
+
+		if (old_auto == intel_dp->color_range_auto &&
+		    old_range == intel_dp->color_range)
+			return 0;
+
 		goto done;
 	}
 

drivers/gpu/drm/i915/intel_hdmi.c

@@ -920,6 +920,9 @@ intel_hdmi_set_property(struct drm_connector *connector,
 	}
 
 	if (property == dev_priv->broadcast_rgb_property) {
+		bool old_auto = intel_hdmi->color_range_auto;
+		uint32_t old_range = intel_hdmi->color_range;
+
 		switch (val) {
 		case INTEL_BROADCAST_RGB_AUTO:
 			intel_hdmi->color_range_auto = true;
@@ -935,6 +938,11 @@ intel_hdmi_set_property(struct drm_connector *connector,
 		default:
 			return -EINVAL;
 		}
+
+		if (old_auto == intel_hdmi->color_range_auto &&
+		    old_range == intel_hdmi->color_range)
+			return 0;
+
 		goto done;
 	}
 

drivers/gpu/drm/i915/intel_sdvo.c

@@ -1930,6 +1930,9 @@ intel_sdvo_set_property(struct drm_connector *connector,
 	}
 
 	if (property == dev_priv->broadcast_rgb_property) {
+		bool old_auto = intel_sdvo->color_range_auto;
+		uint32_t old_range = intel_sdvo->color_range;
+
 		switch (val) {
 		case INTEL_BROADCAST_RGB_AUTO:
 			intel_sdvo->color_range_auto = true;
@@ -1947,6 +1950,11 @@ intel_sdvo_set_property(struct drm_connector *connector,
 		default:
 			return -EINVAL;
 		}
+
+		if (old_auto == intel_sdvo->color_range_auto &&
+		    old_range == intel_sdvo->color_range)
+			return 0;
+
 		goto done;
 	}