In testing the AMD and NVIDIA binary drivers with the Linux 3.12 kernel CPU changes, I was surprised to see the AMD Catalyst 13.11 Beta worked fine with the Linux 3.12 Git kernel as of Monday. The driver built straightaway and worked without needing any patches!
Meanwhile, the NVIDIA 331 Linux Beta doesn't yet work "out of the box" on Linux 3.12. However, through some manual wrangling there is a patch to the NVIDIA driver shim to the Linux kernel and a thread about NVIDIA's support for the latest kernel. Hopefully the next NVIDIA binary driver update due out soon will be here with proper Linux 3.12 kernel compatibility.
This is rare to see the Catalyst Linux kernel compatibility early as usually it doesn't even come for weeks (or months) after the debut, but it's worth pointing out in case anyone wants to try out the Linux 3.12 kernel with their AMD Radeon hardware not using the Gallium3D drivers.