GEM/KMS On FreeBSD Is Working, But Not Ready

Yesterday when writing about the defunct state of the Kernel Graphics Interface project, I mentioned a status update concerning GEM/KMS support for FreeBSD would be on the way. Here's now the state of kernel mode-setting (KMS) and the Graphics Execution Manager (GEM) for the FreeBSD kernel.

Kostik Belousov, the FreeBSD developer that the FreeBSD Foundation is paying to port the Linux graphics code, provided a status update a few days ago to the freebsd-x11 mailing list. On the 30th of June was the first time that Kostik has provided a code drop for the GEM/KMS code. While the code is now publicly available, it's far from ready for integration into the mainline tree. Kostik writes, "Please note that this is not an end-user release, and even _not_ a call for testing. The project is not finished yet, and I expect quite more efforts from me even after the scheduled project end, and from ports/x11 people, before the driver and usermode infrastructure will be ready for the general public consumption."

The current FreeBSD code is unstable and is missing some parts. This GEM/KMS code will also only work with the Intel DRM driver and not the Nouveau or Radeon DRM drivers, which would also require porting TTM (the Translation Table Maps memory manager) and other changes to be made to support under FreeBSD. This FreeBSD effort right now is only focused on bringing up Intel hardware support.

On the Intel GPU FreeBSD Wiki page is where the initial patch can be acquired. The author reports that at least Core i5 Ironlake graphics are working with HDMI output, but the DisplayPort connection still requires additional work and Intel Sandy Bridge support is currently broken. Likewise, Intel "Gen2" and "Gen3" support is most likely broken for now and that supporting them is a low priority.

The FreeBSD code requires a patch against the libdrm Git master, but then works with Git master for dri2proto, Intel DDX (xf86-video-intel), and Mesa on Intel hardware. The FreeBSD patch also goes against the current head code (for the future FreeBSD 9.0 release) and not the stable FreeBSD-8.

It's nice that this project is actually beginning to produce Intel KMS/DRM with Mesa working atop FreeBSD, but it's far from being ready and doesn't yet do any good for NVIDIA (via the Nouveau driver) or ATI/AMD Radeon (via the Radeon driver) drivers on FreeBSD. At least for NVIDIA users they have the proprietary NVIDIA driver that can be used while AMD offers no Catalyst driver for BSD operating systems.