drm/edid: Allow non-fatal checksum errors in CEA blocks

Switches will try to update the topology address and not correctly fix
up the checksum, so just let it slide.

https://bugs.freedesktop.org/28229

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f569ae88ab38..c1981861bbbd 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -147,7 +147,10 @@ drm_edid_block_valid(u8 *raw_edid)
                 csum += raw_edid[i];
         if (csum) {
                 DRM_ERROR("EDID checksum is invalid, remainder is %d\n", csum);
-                goto bad;
+
+                /* allow CEA to slide through, switches mangle this */
+                if (raw_edid[0] != 0x02)
+                        goto bad;
         }
 
         /* per-block-type checks */