A different upside-down problem (Linux)

[Bog Doingus]

I have my monitor hanging upside down. It's very stylish. On starting Amnesia in Ubuntu, my monitor orientation flips from upside down to normal in Catalyst Control Center. I can flip it back, but when I tab back into Amnesia it flips again. Weird! This only happens in full screen; I can play the game windowed just fine, but where's the fun in that?
Anyone know a cause/workaround?