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>

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f569ae8..c198186 100644 (file)
--- 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 */