drm/edid: Fix up partially corrupted headers
We'll still fail the block if it fails the EDID checksum though.
See also: http://bugzilla.redhat.com/534120
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 2820082..bdea313 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -123,16 +123,21 @@
*/
static bool edid_is_valid(struct edid *edid)
{
- int i;
+ int i, score = 0;
u8 csum = 0;
u8 *raw_edid = (u8 *)edid;
- if (memcmp(edid->header, edid_header, sizeof(edid_header)))
+ for (i = 0; i < sizeof(edid_header); i++)
+ if (raw_edid[i] == edid_header[i])
+ score++;
+
+ if (score == 8) ;
+ else if (score >= 6) {
+ DRM_DEBUG("Fixing EDID header, your hardware may be failing\n");
+ memcpy(raw_edid, edid_header, sizeof(edid_header));
+ } else
goto bad;
- if (edid->version != 1) {
- DRM_ERROR("EDID has major version %d, instead of 1\n", edid->version);
- goto bad;
- }
+
for (i = 0; i < EDID_LENGTH; i++)
csum += raw_edid[i];
if (csum) {
@@ -140,6 +145,11 @@
goto bad;
}
+ if (edid->version != 1) {
+ DRM_ERROR("EDID has major version %d, instead of 1\n", edid->version);
+ goto bad;
+ }
+
if (edid->revision > 4)
DRM_DEBUG("EDID minor > 4, assuming backward compatibility\n");