Comment 27 for bug 855124

Well that rules out the possibility that the hardware GMBUS handles the failure more graceful.

To determine if VGA is connected we first check a hotplug status bit in a register. So determining if it is disconnected is quick and easy.

For everything else, we more or less, probe for an EDID and check that EDID corresponds with the limitations of the link. (There are many machines out there that share a single DDC bus between multiple devices, and so the EDID you receive might be for a different encoder.)

Next step is to dive into the specs and see if there is a method for quickly determining unconnected status that we've overlooked all these years...

Besides which the timeout for the HDMI is inexplicably long.