Building upon the massive DRM GPU driver changes in Linux 3.5 and the DMA-BUF 3.5 pull, there's now the pull from David Airlie that ties in the DRM driver changes to what landed in the DMA-BUF pull. In particular, the DRM drivers have been hooked into the PRIME MMAP/VMAP handling support. The groundwork for DMA-BUF PRIME was laid in Linux 3.4.
There's VMAP export support for the Intel, Radeon, and Nouveau drivers and then VMAP import support for UDL, the DisplayLink DRM driver. This will ultimately allow for some interesting possibilities with the Linux multi-seat computers, etc. But if you're hoping this buffer sharing work in the Linux 3.5 kernel will suddenly allow for proper NVIDIA Optimus, NVIDIA SLI, and AMD CrossFire, we're not there yet.
This "drm prime mmap/vmap" pull can be found at LKML.org.