drm/i915/dp: Attach colorspace property

It attaches the colorspace connector property to a DisplayPort connector.
Based on colorspace change, modeset will be triggered to switch to a new
colorspace.

And in order to distinguish colorspace bwtween DP and HDMI connector, it
adds a handling of drm_mode_create_dp_colorspace_property() to
intel_attach_colorspace_property().

Based on colorspace property value create a VSC SDP packet with appropriate
colorspace. This would help to enable wider color gamut like BT2020 on a
sink device.

v9: Addressed review comments from Ville
  - Add a handling of drm_mode_create_dp_colorspace_property() to
    intel_attach_colorspace_property(). This hunk moved from the previous
    commit.
Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190919195311.13972-6-gwan-gyeong.mun@intel.com

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

@@ -277,7 +277,22 @@ intel_attach_aspect_ratio_property(struct drm_connector *connector)
 void
 intel_attach_colorspace_property(struct drm_connector *connector)
 {
-	if (!drm_mode_create_hdmi_colorspace_property(connector))
+	switch (connector->connector_type) {
+	case DRM_MODE_CONNECTOR_HDMIA:
+	case DRM_MODE_CONNECTOR_HDMIB:
+		if (drm_mode_create_hdmi_colorspace_property(connector))
+			return;
+		break;
+	case DRM_MODE_CONNECTOR_DisplayPort:
+	case DRM_MODE_CONNECTOR_eDP:
+		if (drm_mode_create_dp_colorspace_property(connector))
+			return;
+		break;
+	default:
+		DRM_DEBUG_KMS("Colorspace property not supported\n");
+		return;
+	}
+
 	drm_object_attach_property(&connector->base,
 				   connector->colorspace_property, 0);
 }

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

@@ -6476,6 +6476,8 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
 	else if (INTEL_GEN(dev_priv) >= 5)
 		drm_connector_attach_max_bpc_property(connector, 6, 12);
 
+	intel_attach_colorspace_property(connector);
+
 	if (intel_dp_is_edp(intel_dp)) {
 		u32 allowed_scalers;