drm/i915: Introduce intel_panel_preferred_fixed_mode()

There are a couple of cases where we essentially just want to
get/check the preferred fixed mode of the panel. Add a small
helper for that to abstract away the direct pointer lookup.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220311172428.14685-9-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -582,8 +582,9 @@ static bool intel_dp_can_link_train_fallback_for_edp(struct intel_dp *intel_dp,
 						     int link_rate,
 						     u8 lane_count)
 {
+	/* FIXME figure out what we actually want here */
 	const struct drm_display_mode *fixed_mode =
-		intel_dp->attached_connector->panel.fixed_mode;
+		intel_panel_preferred_fixed_mode(intel_dp->attached_connector);
 	int mode_rate, max_rate;
 
 	mode_rate = intel_dp_link_required(fixed_mode->clock, 18);

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

@@ -45,6 +45,12 @@ bool intel_panel_use_ssc(struct drm_i915_private *i915)
 		&& !(i915->quirks & QUIRK_LVDS_SSC_DISABLE);
 }
 
+const struct drm_display_mode *
+intel_panel_preferred_fixed_mode(struct intel_connector *connector)
+{
+	return connector->panel.fixed_mode;
+}
+
 const struct drm_display_mode *
 intel_panel_fixed_mode(struct intel_connector *connector,
 		       const struct drm_display_mode *mode)

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

@@ -25,6 +25,8 @@ enum drm_connector_status
 intel_panel_detect(struct drm_connector *connector, bool force);
 bool intel_panel_use_ssc(struct drm_i915_private *i915);
 const struct drm_display_mode *
+intel_panel_preferred_fixed_mode(struct intel_connector *connector);
+const struct drm_display_mode *
 intel_panel_fixed_mode(struct intel_connector *connector,
 		       const struct drm_display_mode *mode);
 const struct drm_display_mode *

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

@@ -2932,7 +2932,7 @@ intel_sdvo_lvds_init(struct intel_sdvo *intel_sdvo, int device)
 		}
 	}
 
-	if (!intel_connector->panel.fixed_mode)
+	if (!intel_panel_preferred_fixed_mode(intel_connector))
 		goto err;
 
 	return true;