kernel-5.15/i915_hack_bug_97822.patch

A hack used when investigating https://bugs.freedesktop.org/show_bug.cgi?id=97822.

From 8f6bd6297a9c62f03aa3ff3855ff4a159fddd55a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Thu, 6 Oct 2016 18:30:38 +0300
Subject: [PATCH] drm/i915/hack: Abuse i915.vbt_sdvo_panel_type also for
 LVDS/eDP/DSI

---
 drivers/gpu/drm/i915/intel_bios.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 1f8af87..0404478 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -218,19 +218,25 @@ parse_lfp_panel_data(struct drm_i915_private *dev_priv,
 
 	dev_priv->vbt.lvds_dither = lvds_options->pixel_dither;
 
-	ret = intel_opregion_get_panel_type(dev_priv);
-	if (ret >= 0) {
-		WARN_ON(ret > 0xf);
-		panel_type = ret;
-		DRM_DEBUG_KMS("Panel type: %d (OpRegion)\n", panel_type);
-	} else {
-		if (lvds_options->panel_type > 0xf) {
-			DRM_DEBUG_KMS("Invalid VBT panel type 0x%x\n",
-				      lvds_options->panel_type);
-			return;
+	panel_type = i915.vbt_sdvo_panel_type;
+	if (panel_type == -2)
+		return;
+
+	if (panel_type < 0) {
+		ret = intel_opregion_get_panel_type(dev_priv);
+		if (ret >= 0) {
+			WARN_ON(ret > 0xf);
+			panel_type = ret;
+			DRM_DEBUG_KMS("Panel type: %d (OpRegion)\n", panel_type);
+		} else {
+			if (lvds_options->panel_type > 0xf) {
+				DRM_DEBUG_KMS("Invalid VBT panel type 0x%x\n",
+					lvds_options->panel_type);
+				return;
+			}
+			panel_type = lvds_options->panel_type;
+			DRM_DEBUG_KMS("Panel type: %d (VBT)\n", panel_type);
 		}
-		panel_type = lvds_options->panel_type;
-		DRM_DEBUG_KMS("Panel type: %d (VBT)\n", panel_type);
 	}
 
 	dev_priv->vbt.panel_type = panel_type;