The mm-sources may, for the time being, need to have the 4k-stacks-always-on.patch reversed, at least for nvidia users (5336-r1) it seems to hard lock the machine on startx (if set to y). I've been reversing it by hand for 2.6.5-r2 mm2/3 and that has fixed the problem.
That is a a problem upstream. All we're doing is providing mm-sources (in there entirety) through portage. The 4k stack is slated to go mainstream, so nvidia users are in trouble once it does. Unless, nVidia comes out with a module/driver that supports a 4k stack environment, you're stuck doing it by hand.
This is a problem upstream. I'd recommend taking it up with Andrew/nVidia.
Closed. Not really anything we can do. What about those who don't use binary drivers?