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* [Intel-gfx] [PATCH] drm/edid: fix invalid EDID extension block filtering
@ 2022-03-30 17:04 Jani Nikula
  2022-03-30 17:14 ` Ville Syrjälä
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Jani Nikula @ 2022-03-30 17:04 UTC (permalink / raw)
  To: dri-devel; +Cc: jani.nikula, intel-gfx

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 Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 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;
 	}
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2022-03-31 10:06 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-03-30 17:04 [Intel-gfx] [PATCH] drm/edid: fix invalid EDID extension block filtering Jani Nikula
2022-03-30 17:14 ` Ville Syrjälä
2022-03-31 10:06   ` Jani Nikula
2022-03-30 18:03 ` [Intel-gfx] ✗ Fi.CI.DOCS: warning for " Patchwork
2022-03-30 18:37 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2022-03-30 22:14 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork

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