Nouveau Gets Further Freed From Ctx_Voodoo

One of the issues that was widely discussed when Linus Torvalds brought up finally merging the Nouveau DRM into the Linux 2.6.33 kernel was a microcode problem. The past few generations of NVIDIA graphics processors require this specialized microcode/firmware to be loaded in order to provide acceleration of any sort. At first it was it was a mystery what this microcode actually did, but it turns out that it's used for GPU context switching and the like. This wound up being a sticky situation.

The Nouveau DRM was pulled into the Linux 2.6.33 kernel and the microcode of concern ("ctx_voodoo" as it's been called) was left to be loaded externally rather than embedded in the driver itself due to copyright concerns.

Since then, however, the Nouveau development community had created its own NV40 microcode replacement to alleviate the ctx_voodoo usage for the GeForce 6 generation of graphics cards. Emerging now is also a free software alternative to loading the ctx_voodoo microcode for the NV50/NV8x/NV9x/NVAx class hardware. In other words, the newer NVIDIA graphics processors no longer need to deal with this messy firmware.

Unlike the NV40 firmware replacement, this solution for newer NVIDIA GPUs isn't generated firmware being loaded by the driver, but rather the needed microcode is generated in real-time by the driver. With the massive patch (2,000+ lines of code), the Novueau DRM generates its own ctxprogs firmware without any dependence on any potentially copyrighted NVIDIA firmware.

This embedded ctxprogs and ctxvals generator should work for these newer families of NVIDIA GPUs, but it's quite different from NVIDIA's blob, so the developer (Marcin Kościelnicki) is looking for many individuals to test out this newest code and look for any regressions. The Nouveau Gallium3D driver also needs to be tested using this ctxprogs/ctxvals generator.

This generator isn't yet merged into the Nouveau DRM, but for now the large patch can be found on this web-page. Hopefully it will be tested and ready for merging into the Linux 2.6.34 kernel next month. The message announcing this NV50/NV8x/NV9x/NVAx ctxprog and ctxvals generator can be found on the Nouveau mailing list.