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

Automatic color range selection was added in

commit 55bc60db5988c8366751d3d04dd690698a53412c
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>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 89f89b727900..fc3bd9b4037c 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/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;
         }