RADV Vulkan Driver Continues At Full-Speed Preparing For RDNA3/GFX11 GPUs

Last week I wrote about how well known Mesa developer Samuel Pitoiset who is employed by Valve already started working on GFX11 (RDNA3) support for RADV, the open-source Radeon Vulkan driver in Mesa that isn't officially supported by AMD but remains more popular than their own "AMDVLK" driver. More GFX11/RDNA3 preparation work remains ongoing and it's looking like if trends continue this open-source driver could be ready for RDNA3 graphics cards in time for launch.

AMD doesn't officially support RADV and leaves it up to third parties and the open-source community. Samuel's work on RADV GFX11 support appears to be based on learning design changes about the next-generation GPUs based on AMD's enablement patches to the RadeonSI Gallium3D (OpenGL) driver as well as the AMDGPU LLVM shader compiler back-end changes to upstream LLVM. And then AMD continues enablement on the kernel side with the AMDGPU Direct Rendering Manager driver. It's also possible AMD may be supplying some documentation or details to Valve to aide in this effort and possibly getting access to RDNA3 GPUs prior to the public launch. It's in AMD's interest after all to have good Linux software support regardless if it's their official driver or not.

Following the initial code merged last week, this week brought more GFX11 activity for RADV as well as its associated ACO (AMD Compiler) back-end developed by Valve instead of the AMDGPU LLVM shader compiler. There was a merge request that landed on Tuesday with radv: very preliminary support for GFX11. Samuel noted there, "It's still incomplete but already contains a bunch of changes. I will address the missing bits in separate MRs."

That pull adds around 500 lines of new code, of which some 150 lines are altered/removed of existing code. One interesting bit brought up by this patch series is that with GFX11, Next-Gen Geometry (NGG) is now always enabled. Previously NGG had to be enabled and was causing problems in the early stage of enablement for the open-source drivers but at least there is mature driver support now with NGG always being on for these next-gen GPUs with the legacy path for the hardware removed.

Opened yesterday are merge requests with additional RADV GFX11 bring-up work and fixes as well as the ACO back-end work.

This GFX11 work going into Mesa now for RadeonSI and RADV is for Mesa 22.2, which will reach stable in August, and should be the version in use by autumn distribution updates like Ubuntu 22.10. Likewise the initial kernel support looks like it will be here with v5.19, but to outside observers is not clear how much work remains that has yet to be published/merged. So if the RDNA3/GFX11 support gets squared away in the next few months by the time of these autumn Linux distribution releases there will hopefully be out-of-the-box RDNA3 support ready for these new AMD graphics cards launching in H2.