Comment 30 for bug 575985

When the EDID provided by hardware is invalid or unavailable, there really is little the kernel can do to correct it. In some cases where there is a simple monitor-specific flaw, that can be quirked on a case-by-case basis, however the situation described here is outside that scope, since the EDID is just plain blank.

Disabling use of KMS modesetting (as described in the above comments, and as provided by the upstream bug report) works around the problem but doesn't really "fix" it. A proper fix would be to provide a tool for installing a corrected EDID into the kernel's /lib/firmware/edid. The kernel already supports this, but the tool needs to be provided on the userspace side, e.g. xdiagnose.