Ok, now KMS seems to work much better!
BTW, I'm now wondering how to set resolution when KMS is enabled. "vga=value" doesn't seem to apply to KMS too, so even after googling I'm left in the dark.
If there is no way to do so it's really a pain: KMS sets my monitor to it's maximum capability 1920x1440@60Hz, which is not good (nor readable, it's a 19" CRT!), instead of the reccomended 1280x1024@100Hz (@85Hz would be fine too).
I know I can change the XServer resolution, but I also want to use VTs.
Does anybody know of a way to do so?