If after reading about the recent Nouveau DRM improvements, you were hoping the kernel driver updates fixed-up the situation for the Fermi "NVD0" graphics processors, you are sadly mistaken: it is still a busted mess.
On 20 December I pulled the latest Linux kernel code from the Nouveau kernel tree along with Mesa 7.12-devel Git master, libdrm, and xf86-video-nouveau DDX from Git. In using that code, hardware acceleration is still disabled by default and requires booting the kernel with the "nouveau.noaccel=0" argument so that hardware acceleration is enabled if using an NVD0-class NVIDIA GPU.
The NVD0 (GF119) class "Fermi" graphics processors are the newest NVIDIA hardware that's still pre-Kepler (GeForce 600 series) and among the products are the GeForce 410M, GeForce GT 520, GeForce 520M, GeForce 610M, and Quadro NVS 4200M. For this testing I was using a NVIDIA GeForce GT 520 PCI Express graphics card.
The NVD0 support came to Nouveau later on after the other Fermi GPUs (what the Nouveau developers classify as the NVC0 class). Only with the Linux 3.3 kernel will the Nouveau Fermi (including NVC0) support re-clocking, KMS page-flipping, and other features, but the NVD0 support is even in much worse shape. While NVC0 Fermi GPUs may be slow with the open-source Nouveau driver and possess other shortcomings to the NVIDIA proprietary driver, the NVD0 support with the latest Nouveau code as tried on the GeForce GT 520 was useless.