Comment 37 for bug 1243557

There was a bug introduced in 3.11 (I think) for nvc1,nvd7,nvd9 which is fixed by http://cgit.freedesktop.org/nouveau/linux-2.6/commit/?id=89ad841ffd3eccd06e2a12649f4a5028ecb973b7. I'm not sure what the user-visible effect of the bug is, I suspect it depends on a lot of local configuration settings. I don't know if this will help you, but I believe it's worth trying.