The reverse-engineered open-source Nouveau driver has received its own FUC microcode implementation that frees it from having to use the binary microcode produced by the proprietary NVIDIA Linux graphics driver for the GeForce 600 "Kepler" graphics processors, but there's still problems ahead in supporting this latest-generation hardware.
Committed to the Nouveau DRM driver development repository last week was an initial FUC implementation
for "NVE0", a.k.a. Kepler GPUs. The FUC implementation, which is based upon the Fermi FUC code, amounts to just over 3,000 lines of code. The commit description read:
drm/nve0/gr: initial fuc implementation, based on fermi's code
Currently identical except the available chipset register lists. This will *not* currently work and is disabled by default because of this. May get merged again later, remains to be seen what further changes will be required.
But then following this initial commit was another
related to the NVE0 FUC. This follow-up commit avoided bashing 0x404160
by changing around about 300 lines of code. As a result of this commit, the FUC loads on Kepler and for NVE4 hardware can at least provide acceleration support for a frame-buffer console, X.Org, glxgears, and OpenArena.
later, the Nouveau Kepler-based Fermi FUC was enabled by default. However, even after this commit the hardware-accelerated GeForce 600 series support is still disabled by default due to outstanding bugs.
The FUC (Flexible micro-controller it's been called, among other terms) microcode is needed for modern hardware in order for accelerated support on modern NVIDIA GPUs. Like for Kepler, it initially took several months for Fermi FUC microcode to be developed
so that first the NVIDIA driver didn't need to be loaded followed by running MMIOtrace in order to extract your own microcode for initializing the hardware when running the Nouveau driver.
When the NVIDIA GeForce 600 graphics cards were launched back in March there was the big surprise of same-day Nouveau support
as the community developers somehow got early access to a few GeForce GTX 680 graphics cards. However, the needing of this FUC microcode has limited the open-source Nouveau support so far of this new hardware. There were also some early Kepler bugs
. The Nouveau Kepler support works with OpenGL acceleration works
but is quite slow at the moment due to the lack of proper graphics core / memory re-clocking, which is also defeating the use of the open-source driver on the latest NVIDIA GPUs.
This continued Nouveau work by Red Hat's Ben Skeggs is terrific and hopefully by the time the Linux 3.7 kernel merge window opens they will be able to have Kepler acceleration support by default. Unfortunately by the time this supported kernel ends up in most non-rolling-release distributions, Kepler will have been around one year old.... At least Nouveau has already begun work on unreleased GK110 "Kepler 2" support