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drm/edid: Fix up partially corrupted headers

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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>
This commit is contained in:
Adam Jackson
2009-11-23 14:23:06 -05:00
committed by Dave Airlie
parent 47ee4ccf74
commit 862b89c069
1 changed files with 16 additions and 6 deletions
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22
drivers/gpu/drm/drm_edid.c
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@@ -123,16 +123,21 @@ static const u8 edid_header[] = {
*/ */
static bool edid_is_valid(struct edid *edid) static bool edid_is_valid(struct edid *edid)
{ {
int i; int i, score = 0;
u8 csum = 0; u8 csum = 0;
u8 *raw_edid = (u8 *)edid; 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; 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++) for (i = 0; i < EDID_LENGTH; i++)
csum += raw_edid[i]; csum += raw_edid[i];
if (csum) { if (csum) {
@@ -140,6 +145,11 @@ static bool edid_is_valid(struct edid *edid)
goto bad; 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) if (edid->revision > 4)
DRM_DEBUG("EDID minor > 4, assuming backward compatibility\n"); DRM_DEBUG("EDID minor > 4, assuming backward compatibility\n");