From 91d983e9ccdfd09acd4721f9e6879559f382c3c0 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Wed, 30 Mar 2022 20:04:26 +0300
Subject: drm/edid: fix invalid EDID extension block filtering
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Git-commit: 3aefc722ff52076407203b6af9713de567993adf
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
The invalid EDID block filtering uses the number of valid EDID
extensions instead of all EDID extensions for looping the extensions in
the copy. This is fine, by coincidence, if all the invalid blocks are at
the end of the EDID. However, it's completely broken if there are
invalid extensions in the middle; the invalid blocks are included and
valid blocks are excluded.
Fix it by modifying the base block after, not before, the copy.
Fixes: 14544d0937bf ("drm/edid: Only print the bad edid when aborting")
Reported-by: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220330170426.349248-1-jani.nikula@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/drm_edid.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index d79b06f7f34c..8829120470ab 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2031,9 +2031,6 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
connector_bad_edid(connector, edid, edid[0x7e] + 1);
- edid[EDID_LENGTH-1] += edid[0x7e] - valid_extensions;
- edid[0x7e] = valid_extensions;
-
new = kmalloc_array(valid_extensions + 1, EDID_LENGTH,
GFP_KERNEL);
if (!new)
@@ -2050,6 +2047,9 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
base += EDID_LENGTH;
}
+ new[EDID_LENGTH - 1] += new[0x7e] - valid_extensions;
+ new[0x7e] = valid_extensions;
+
kfree(edid);
edid = new;
}
--
2.38.1