drm/i915/dp: Initialize eDP fixed mode in intel_dp_init

Since we do EDID caching in intel_dp_init, we can do the fixed mode
initialization there too. This should not change the functionality apart
from initializing fixed mode earlier. Particularly retain the behaviour of
only falling back to VBT if EDID is not available to not regress

commit 47f0eb2234a2a1c790825393bbaccfadf82463d3
Author: Keith Packard <keithp@keithp.com>
Date:   Mon Sep 19 14:33:26 2011 -0700

    drm/i915: Only use VBT panel mode on eDP if no EDID is found

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -2401,42 +2401,20 @@ static int intel_dp_get_modes(struct drm_connector *connector)
 {
 	struct intel_dp *intel_dp = intel_attached_dp(connector);
 	struct drm_device *dev = intel_dp->base.base.dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret;
 
 	/* We should parse the EDID data and find out if it has an audio sink
 	 */
 
 	ret = intel_dp_get_edid_modes(connector, &intel_dp->adapter);
-	if (ret) {
-		if (is_edp(intel_dp) && !intel_dp->panel_fixed_mode) {
-			struct drm_display_mode *newmode;
-			list_for_each_entry(newmode, &connector->probed_modes,
-					    head) {
-				if ((newmode->type & DRM_MODE_TYPE_PREFERRED)) {
-					intel_dp->panel_fixed_mode =
-						drm_mode_duplicate(dev, newmode);
-					break;
-				}
-			}
-		}
+	if (ret)
 		return ret;
-	}
 
-	/* if eDP has no EDID, try to use fixed panel mode from VBT */
-	if (is_edp(intel_dp)) {
-		/* initialize panel mode from VBT if available for eDP */
-		if (intel_dp->panel_fixed_mode == NULL && dev_priv->lfp_lvds_vbt_mode != NULL) {
-			intel_dp->panel_fixed_mode =
-				drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);
-			if (intel_dp->panel_fixed_mode) {
-				intel_dp->panel_fixed_mode->type |=
-					DRM_MODE_TYPE_PREFERRED;
-			}
-		}
-		if (intel_dp->panel_fixed_mode) {
-			struct drm_display_mode *mode;
-			mode = drm_mode_duplicate(dev, intel_dp->panel_fixed_mode);
+	/* if eDP has no EDID, fall back to fixed mode */
+	if (is_edp(intel_dp) && intel_dp->panel_fixed_mode) {
+		struct drm_display_mode *mode;
+		mode = drm_mode_duplicate(dev, intel_dp->panel_fixed_mode);
+		if (mode) {
 			drm_mode_probed_add(connector, mode);
 			return 1;
 		}
@@ -2633,6 +2611,7 @@ intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
 	struct intel_dp *intel_dp;
 	struct intel_encoder *intel_encoder;
 	struct intel_connector *intel_connector;
+	struct drm_display_mode *fixed_mode = NULL;
 	const char *name = NULL;
 	int type;
 
@@ -2797,6 +2776,7 @@ intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
 
 	if (is_edp(intel_dp)) {
 		bool ret;
+		struct drm_display_mode *scan;
 		struct edid *edid;
 
 		ironlake_edp_panel_vdd_on(intel_dp);
@@ -2826,6 +2806,23 @@ intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
 			drm_edid_to_eld(connector, edid);
 			intel_dp->edid = edid;
 		}
+
+		/* prefer fixed mode from EDID if available */
+		list_for_each_entry(scan, &connector->probed_modes, head) {
+			if ((scan->type & DRM_MODE_TYPE_PREFERRED)) {
+				fixed_mode = drm_mode_duplicate(dev, scan);
+				break;
+			}
+		}
+
+		/* fallback to VBT if available for eDP */
+		if (!fixed_mode && dev_priv->lfp_lvds_vbt_mode) {
+			fixed_mode = drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);
+			if (fixed_mode)
+				fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
+		}
+		intel_dp->panel_fixed_mode = fixed_mode;
+
 		ironlake_edp_panel_vdd_off(intel_dp, false);
 	}