This code isn't as exciting as the Tegra DRM driver or last week's 2D acceleration code provided by NVIDIA's growing fondness of open-source for Tegra, but it's still important nevertheless. This helper code will eventually be used when there is a new X.Org/DDX driver for supporting the Tegra 2D acceleration and communicating with the kernel DRM driver.
The NVIDIA Tegra DRM library support amounts to a couple hundred lines of code that provides a basic API and two IOCTLs for creating Tegra-specific GEM. For the eventual X.Org graphics driver for handling open-source Tegra, it's looking like that it will be based upon a forked version of the generic xf86-video-modesetting driver and then the various Tegra-specific acceleration bits layered atop. There was also brief talk about forking the dead xf86-video-nv driver, but that path seems much less likely.
The current libdrm patch can be found on the mailing list. Expect more patches out of NVIDIA and Avionic Design going forward. If you missed it, read the back-story of the recent open-source NVIDIA work.