drm/i915: Parse VRR capability from VBT

VBT seems to have an extra flag for VRR vs. not. Let's consult
that for eDP panels.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220531191844.11313-2-ville.syrjala@linux.intel.com

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

@@ -1292,6 +1292,8 @@ parse_power_conservation_features(struct drm_i915_private *i915,
 	const struct bdb_lfp_power *power;
 	u8 panel_type = panel->vbt.panel_type;
 
+	panel->vbt.vrr = true; /* matches Windows behaviour */
+
 	if (i915->vbt.version < 228)
 		return;
 
@@ -1312,6 +1314,9 @@ parse_power_conservation_features(struct drm_i915_private *i915,
 
 	if (i915->vbt.version >= 232)
 		panel->vbt.edp.hobl = power->hobl & BIT(panel_type);
+
+	if (i915->vbt.version >= 233)
+		panel->vbt.vrr = power->vrr_feature_enabled & BIT(panel_type);
 }
 
 static void

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

@@ -294,6 +294,8 @@ struct intel_vbt_panel_data {
 	unsigned int lvds_dither:1;
 	unsigned int bios_lvds_val; /* initial [PCH_]LVDS reg val in VBIOS */
 
+	bool vrr;
+
 	u8 seamless_drrs_min_refresh_rate;
 	enum drrs_type drrs_type;
 

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

@@ -15,19 +15,29 @@ bool intel_vrr_is_capable(struct intel_connector *connector)
 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 	struct intel_dp *intel_dp;
 
-	if (connector->base.connector_type != DRM_MODE_CONNECTOR_eDP &&
-	    connector->base.connector_type != DRM_MODE_CONNECTOR_DisplayPort)
-		return false;
-
-	intel_dp = intel_attached_dp(connector);
 	/*
 	 * DP Sink is capable of VRR video timings if
 	 * Ignore MSA bit is set in DPCD.
 	 * EDID monitor range also should be atleast 10 for reasonable
 	 * Adaptive Sync or Variable Refresh Rate end user experience.
 	 */
+	switch (connector->base.connector_type) {
+	case DRM_MODE_CONNECTOR_eDP:
+		if (!connector->panel.vbt.vrr)
+			return false;
+		fallthrough;
+	case DRM_MODE_CONNECTOR_DisplayPort:
+		intel_dp = intel_attached_dp(connector);
+
+		if (!drm_dp_sink_can_do_video_without_timing_msa(intel_dp->dpcd))
+			return false;
+
+		break;
+	default:
+		return false;
+	}
+
 	return HAS_VRR(i915) &&
-		drm_dp_sink_can_do_video_without_timing_msa(intel_dp->dpcd) &&
 		info->monitor_range.max_vfreq - info->monitor_range.min_vfreq > 10;
 }