Comment 70 for bug 440411

The patch http://bugzilla.kernel.org/attachment.cgi?id=24339 contains the code that can be removed in case BIOS is not used for the VBT setup. This code has been currently dropped from the vanilla kernel, if I've understood correctly. I think the best fix would be to keep this code but to skip VBT of it if a known bad BIOS is detected.

If I'm reading the code correctly, then both dp_is_present_in_vbt() and hdmi_is_present_in_vbt() should be modified to always return 1 in case of a known broken BIOS. It could be wise to add a kernel flag to allow forcing the BIOS as broken to have a quick fix for a BIOS that is later found to be broken (such a flag could be used until the kernel is teached about such BIOS).