There's an Intel KMS/DRM driver to FreeBSD 9.1, but that's it as far as ports go of the Linux DRM drivers. However, the AMD KMS driver along with support for TTM memory management within the FreeBSD kernel is taking shape quickly.
The latest status update as of this week (14 March) for the AMD GPU KMS support in the FreeBSD world is working on a 9-STABLE port (rather than targeting FreeBSD 10 code), fixing of memory leaks and locking issues, and there is now proper EDID reading support so the correct resolution is used by the X.Org Server.
Previous to that latest update, the AMD KMS driver was running a KMS-enabled X.Org Server with the Firefox web-browser, but there were still a huge amount of debug logs and stability issues after a few minutes.
For those FreeBSD users with the AMD Radeon graphics hardware, updates to the state of this open-source graphics driver can be found on the FreeBSD Wiki. AMD graphics support is very important for FreeBSD since AMD doesn't release any Catalyst driver for the operating system, while NVIDIA offers its high quality proprietary driver for the OS.