AMD GPU

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This guide is about setting up NixOS to correctly use your AMD Graphics card if it is relatively new (aka, after the GCN architecture).

Make the kernel use the correct driver early

The kernel can load the correct driver right away:

boot.initrd.kernelModules = [ "amdgpu" ];

XServer

Make sure Xserver uses the `amdgpu` driver in your configuration.nix:

services.xserver.enable = true;
services.xserver.videoDrivers = [ "amdgpu" ];

Enable Southern Islands (SI) and Sea Islands (CIK) support

The oldest architectures that AMDGPU supports are Southern Islands (SI, i.e. GCN 1) and Sea Islands (CIK, i.e. GCN 2), but support for them is disabled by default. To use AMDGPU instead of the radeon driver, you can set the kernel parameters:

# for Southern Islands (SI i.e. GCN 1) cards
boot.kernelParams = [ "radeon.si_support=0" "amdgpu.si_support=1" ];
# for Sea Islands (CIK i.e. GCN 2) cards
boot.kernelParams = [ "radeon.cik_support=0" "amdgpu.cik_support=1" ];

Doing this is required to use Vulkan on these cards, as the radeon driver doesn't support it.

HIP

Most software has the HIP libraries hard-coded. You can work around it on NixOS by using:

systemd.tmpfiles.rules = [
    "L+    /opt/rocm/hip   -    -    -     -    ${pkgs.rocmPackages.clr}"
  ];

Blender

Hardware accelerated rendering can be achieved by using the package blender-hip.

OpenCL

hardware.opengl.extraPackages = with pkgs; [
  rocmPackages.clr.icd
];

You should also install the clinfo package to verify that OpenCL is correctly setup (or check in the program you use to see if it is now available, such as in Darktable).

environment.systemPackages = with pkgs; [
  clinfo
];

Radeon 500 series (aka Polaris)

As of ROCm 4.5, AMD has disabled OpenCL on Polaris based cards. This can be re-enabled by setting the environment variable ROC_ENABLE_PRE_VEGA=1

environment.variables = {
  ROC_ENABLE_PRE_VEGA = "1";
};

Older GPUs (TeraScale)

For graphics cards older than GCN 1 (or for any GCN using the "radeon" driver), enable OpenCL by adding Clover instead of the ROCm ICD:

hardware.opengl.extraPackages = [
  # NOTE: at some point GPUs in the R600-family and newer
  # may need to replace this with the "rusticl" ICD;
  # and GPUs in the R500-family and older may need to
  # pin the package version or backport/patch this back in
  # - https://www.phoronix.com/news/Mesa-Delete-Clover-Discussion
  # - https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19385
  pkgs.mesa.opencl
];

Installing `mesa.opencl` with `nix-shell` will not work; it needs to be configured at a higher level for the OpenCL ICD loader, which only searches fixed locations.

Vulkan

Vulkan is already enabled by default (using Mesa RADV) on 64 bit applications. The settings to control it for 32 bit applications is:

hardware.opengl.driSupport32Bit = true; # For 32 bit applications

Soon this will be changed to

hardware.graphics.enable32Bit = true; # For 32 bit applications


AMDVLK

The AMDVLK drivers can be used in addition to the Mesa RADV drivers. The program will choose which one to use:

hardware.opengl.extraPackages = with pkgs; [
  amdvlk
];
# For 32 bit applications 
hardware.opengl.extraPackages32 = with pkgs; [
  driversi686Linux.amdvlk
];

More information can be found here: https://nixos.org/manual/nixos/unstable/index.html#sec-gpu-accel-vulkan

Problems

Dual Monitors

If you encounter problems having multiple monitors connected to your GPU, adding `video` parameters for each connector to the kernel command line sometimes helps.

For example:

boot.kernelParams = [
  "video=DP-1:2560x1440@144"
  "video=DP-2:2560x1440@144"
];

With the connector names (like `DP-1`), the resolution and frame rate adjusted accordingly.

To figure out the connector names, execute the following command while your monitors are connected:

head /sys/class/drm/*/status