The 1.0.1 version contiains some fixes, mentioned here: http://cgit.freedesktop.org/nouveau/xf86-video-nouveau/log/ Reproducible: Always
It's already in the tree, but it seems to be unusable since there's no mesa ebuild that allows for a recent libdrm which is required for nouveau 1.0.1. Would be nice to hear about status updates here.
There was an API break between libdrm-2.4.33 and 2.4.34. Currently no release of mesa works with new libdrm. xf86-video-nouveau-1.0.1 needs new libdrm.