I wasn't able to find a solution for this one, although I see it's not a new thing. I haven't experienced it before, it just started happening half an hohur ago. Apparently it's Intel graphic specific, but I am not 100% sure.
When I switch to full screen mode in Flash, it causes X to crash, which in turn logs me out. And before it does, the video either freezes in full screen after a few seconds (audio's fine), or runs smoothly until the log out.
I'm not sure how to debug this. Any help?