From 1781b12eed4db6aff22e5865d127da5127789067 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Wed, 4 May 2022 18:04:36 +0300
Subject: drm/i915/bios: Assume panel_type==0 if the VBT has bogus data
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Git-commit: 4d1b21605d3922c18ceea7fb610a0e17cf7700f9
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Just assume panel_type==0 always if the VBT gives us bogus data.
We actually already do this everywhere else except in
parse_panel_options() since we just leave i915->vbt.panel_type
zeroed. This also seems to be what Windows does.

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/20220504150440.13748-6-ville.syrjala@linux.intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/display/intel_bios.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index cc0fae588e09..20b15732c648 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -619,13 +619,14 @@ parse_panel_options(struct drm_i915_private *i915)
 	} else {
 		if (lvds_options->panel_type > 0xf) {
 			drm_dbg_kms(&i915->drm,
-				    "Invalid VBT panel type 0x%x\n",
+				    "Invalid VBT panel type 0x%x, assuming 0\n",
 				    lvds_options->panel_type);
-			return;
+			panel_type = 0;
+		} else {
+			panel_type = lvds_options->panel_type;
+			drm_dbg_kms(&i915->drm, "Panel type: %d (VBT)\n",
+				    panel_type);
 		}
-		panel_type = lvds_options->panel_type;
-		drm_dbg_kms(&i915->drm, "Panel type: %d (VBT)\n",
-			    panel_type);
 	}
 
 	i915->vbt.panel_type = panel_type;
-- 
2.38.1