I did also do all the plugging and unplugging and switching without sleepies. It's only the sleepytime that makes it happen. Once it's happened, nothing short of the Act Of God (killall) fixes it.

I might do the direct-dvi-connect thingy as a test eventually, but the way things are mounted and wired now, that would take an act of congress. (or a mail order for that 10 foot DVI-only cable.) I agree that I need to test this. I can see that there's a possibility that the problem will go away completely if I use a real DVI cable instead of an HDMI cable. Unfortunately, not gonna happen over the next few days, as I'm generally really busy of late... Last night was an unusually "slow" night (had only 10 things to do instead of 20:) ).