24.11 & AMD GPU: How to use Mesa RADV instead of amdvlk

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1

tldr: After the update to NixOS 24.11 I could not get the RADV Vulkan driver installed on my Laptop. It has an AMD Ryzen 7 4800H CPU/GPU.

Before 24.11 Vulkan was enabled by default (using Mesa RADV) [1]:

hardware.opengl = {
  driSupport = true;
  driSupport32Bit = true;
};

Now these settings were changed to [2]:

hardware.graphics = {
  enable = true;
  enable32Bit = true;
};

However, with these new settings both vulkaninfo and vkcube-wayland indicate that no Vulkan drivers are available on my device.

I’ll post the output of those two commands in some minutes.

2

You shouldn’t have to do anything other than those two hardware.graphics settings; mesa and radv should be included out of the box. And indeed that works for me on 24.11 with an AMD GPU.

3

Many thanks for confirming this so quickly @ElvishJerricco! I don’t know why, but I can’t reproduce my error anymore - sorry for taking your time with this false-positive. All I did is update nixpkgs and some config cleanup :see_no_evil: Vulkan (and OpenGL, VA-API) work with only the two hardware.graphics options!

I even tried it without setting any hardware.graphics, as the hardware.graphics.enable option has this comment:

Enabled by default by the corresponding modules, so you do not usually have to set it yourself.

And Vulkan does still work :tada:

Only thing left regarding hardware acceleration is VDPAU. But here I am not quite sure if that was working before upgrading to NixOS 24.11. Here is the error I get when verifying it:

nix-shell -p vdpauinfo --run vdpauinfo

display: :0   screen: 0
Failed to open VDPAU backend libvdpau_nvidia.so: cannot open shared object file: No such file or directory
Error creating VDPAU device: 1
4

I’ll try out hardware.graphics.extraPackages for that and report back soon.

5

Even with the following extraPackages, VDPAU was not working:

# VDPAU driver with OpenGL/VAAPI backend
pkgs.libvdpau-va-gl
# VDPAU driver for the VAAPI library
pkgs.vaapiVdpau

According to the Arch wiki, VDPAU might need configuration [3]. This did the trick for me:

env VDPAU_DRIVER=radeonsi nix-shell -p vdpauinfo --run vdpauinfo

display: :0   screen: 0
API version: 1
Information string: G3DVL VDPAU Driver Shared Library version 1.0

Video surface:

name   width height types
-------------------------------------------
420    16384 16384  NV12 YV12 
...

Edit: I just confirmed that VDPAU still works without (redundantly) providing those extraPackages. The only thing that is missing is the environment variable VDPAU_DRIVER with the correct driver in use.

This seems to be an older issue, see e.g. Vdpau through vaapi - #2 by ony