GPU on non-NixOS systems

To access the GPU, programs need access to OpenGL and Vulkan libraries. While this works transparently on NixOS, it does not on other Linux systems. A solution is provided by NixGL, which can be integrated into Home Manager.

To enable the integration, import NixGL into your home configuration, either as a channel, or as a flake input passed via extraSpecialArgs. Then, set the nixGL.packages option to the package set provided by NixGL.

Once integration is enabled, it can be used in two ways: as Nix functions for wrapping programs installed via Home Manager, and as shell commands for running programs installed by other means (such as nix shell). In either case, there are several wrappers available. They can be broadly categorized

by vendor: as Mesa (for Free drivers of all vendors) and Nvidia (for Nvidia-specific proprietary drivers).
by GPU selection: as primary and secondary (offloading).

For example, the mesa wrapper provides support for running programs on the primary GPU for Intel, AMD and Nouveau drivers, while the mesaPrime wrapper does the same for the secondary GPU.

Note: when using Nvidia wrappers together with flakes, your home configuration will not be pure and needs to be built using home-manager switch --impure. Otherwise, the build will fail, complaining about missing attribute currentTime.

Wrapper functions are available under config.lib.nixGL.wrappers. However, it can be more convenient to use the config.lib.nixGL.wrap alias, which can be configured to use any of the wrappers. It is intended to provide a customization point when the same home configuration is used across several machines with different hardware. There is also the config.lib.nixGL.wrapOffload alias for two-GPU systems.

Another convenience is that all wrapper functions are always available. However, when nixGL.packages option is unset, they are no-ops. This allows them to be used even when the home configuration is used on NixOS machines. The exception is the prime-offload script which ignores nixGL.packages and is installed into the environment whenever nixGL.prime.installScript is set. This script, which can be used to start a program on a secondary GPU, does not depend on NixGL and is useful on NixOS systems as well.

Below is an abbreviated example for an Optimus laptop that makes use of both Mesa and Nvidia wrappers, where the latter is used in dGPU offloading mode. It demonstrates how to wrap mpv to run on the integrated Intel GPU, wrap FreeCAD to run on the Nvidia dGPU, and how to install the wrapper scripts. It also wraps Xonotic to run on the dGPU, but uses the wrapper function directly for demonstration purposes.

{ config, lib, pkgs, nixGL, ... }:
{
  nixGL.packages = nixGL.packages;
  nixGL.defaultWrapper = "mesa";
  nixGL.offloadWrapper = "nvidiaPrime";
  nixGL.installScripts = [ "mesa" "nvidiaPrime" ];

  programs.mpv = {
    enable = true;
    package = config.lib.nixGL.wrap pkgs.mpv;
  };

  home.packages = [
    (config.lib.nixGL.wrapOffload pkgs.freecad)
    (config.lib.nixGL.wrappers.nvidiaPrime pkgs.xonotic)
  ];
}

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GPU on non-NixOS systems

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