Comment 26 for bug 655413

OK, I tried your tip, and when resuming, I could not get my screen back, at all. However, one little thing did run better: the keyboard wasn't locked, and I managed to switch terminals, log in as root and type reboot, all without a screen.

I also wonder: I generally boot with nomodeset (because there is another problem with edid, so I don't get my full screen resolution unless doing so - the subject of a separate, older bug report of mine). Does adding radeon.modeset=0 add anything? I tried with and without, and had the same result every time, so I don't know whether the radeon parameter added anything.

Anyway, given that even without X I have this problem, I believe we must conclude this is a kernel issue.