Karol Herbst of Red Hat has merged the initial NVIDIA Ada Lovelace support for the Nouveau Gallium3D driver to get OpenGL working. This is separate from the NVK Vulkan driver effort and again ultimately not too useful until the GSP and re-clocking support are sorted out kernel-side.
Herbst commented in the Mesa MR providing this initial NVIDIA GeForce RTX 40 series support:
"Seems to just work. The 3D subchannel appears to be identical to Ampere. Nvidia didn't publish the compute class headers yet, so maybe something is up there.
CTS run looks good enough
Note: this contains a Cc stable tag, so we get that enablement shipped to users a bit faster."
A step in the right direction but it will be a while before the Nouveau DRM kernel driver is ready to provide good support for modern NVIDIA GPUs with this open-source driver and most Linux gamers/enthusiasts will also be waiting on the NVK Vulkan driver to get into good shape. For now the Intel and AMD Radeon Linux graphics driver stacks provide the much better open-source experience.