NVIDIA

Card type

• MXM / output-providing card (shows as VGA Controller in lspci), i.e. graphics card in desktop computer or in some laptops
• muxless/non-MXM Optimus cards have no display outputs and show as 3D Controller in lspci output, seen in most modern consumer laptops

Non-optimus mode

You need MXM card. Follow NVIDIA Graphics Cards section in official manual.

In case of laptop you may also need to use a BIOS option to select which card to use for the internal display.

Optimus

Only for laptops. There are currently two solutions available under NixOS:

Bumblebee

Unofficial solution.

• Pros:
  • works out of the box, just start the game via the primusrun or optirun wrapper
  • works under existing X11 server

• Cons:
  • some performance penalties, running under wayland decreases performance even more
  • things like Vulkan, CUDA and OpenCL are problematic to configure

Use option

hardware.bumblebee.enable = true;

Nvidia PRIME

Official solution by nvidia.

dynamic mode

Like with Bumblebee, in this mode nvidia card is only turned on by need, other time it stays in power saving mode.

• Pros:
  • Has better performance than Bumblebee
  • Vulkan, CUDA and OpenCL work, though CUDA needs an additional device creation rule https://github.com/NixOS/nixpkgs/blob/05e375d7103ac51e2da917965c37246c99f1ae4f/nixos/modules/hardware/video/nvidia.nix#L72
  • Using a pure wayland setup is supported

• Cons:
  • There are still some slight issues noted at the top of script
  • Launches new X11 server (and so it's preferable to run the WM/DE alongside the program)

1. Configure NixOS to allow Intel and Nvidia X.Org drivers coexist together (only needed because NixOS forces LD_LIBRARY_PATH variable propagation), and also to disable nvidia card by default.

/etc/nixos/configuration.nix

{
  # disable card with bbswitch by default
  hardware.nvidiaOptimus.disable = true;
  # install nvidia drivers in addition to intel one
  hardware.opengl.extraPackages = [ pkgs.linuxPackages.nvidia_x11.out ];
  hardware.opengl.extraPackages32 = [ pkgs.linuxPackages.nvidia_x11.lib32 ];
}

2. Download primerun script.

Like with Bumblebee, start the game via primerun.sh.

static mode

In this mode nvidia card is turned on constantly, having impact on laptop battery and health.

• Pros:
  • better performance than Bumblebee
  • out of box experience
  • works under existing X11 server

• Cons:
  • nvidia is turned on constantly
  • things like Vulkan, CUDA and OpenCL are not tested
  • no wayland support

/etc/nixos/configuration.nix

{
  services.xserver.videoDrivers = [ "nvidia" ];
  hardware.nvidia.optimus_prime.enable = true;
  # Bus ID of the NVIDIA GPU. You can find it using lspci
  hardware.nvidia.optimus_prime.nvidiaBusId = "PCI:1:0:0";
  # Bus ID of the Intel GPU. You can find it using lspci
  hardware.nvidia.optimus_prime.intelBusId = "PCI:0:2:0";
  
}

non-NixOS case

• The nixGL project provides wrapper to use GL drivers outside of NixOS. You need to have nvidia drivers installed on your distro (for kernel modules). Then supply nvidia driver version you use on host system to nixGL.
• Optimus only. Primerun will build nvidia kernel modules against your currently running kernel.

CUDA

There some possible ways to setup a development environment using CUDA on NixOS. This can accomplished in the following ways:

• By making a FHS user env

cuda-fsh.nix

{ pkgs ? import <nixpkgs> {} }:

let fhs = pkgs.buildFHSUserEnv {
        name = "cuda-env";
        targetPkgs = pkgs: with pkgs;
               [ git
                 gitRepo
                 gnupg
                 autoconf
                 curl
                 procps
                 gnumake
                 utillinux
                 m4
                 gperf
                 unzip
                 cudatoolkit
                 linuxPackages.nvidia_x11
                 libGLU_combined
		 xorg.libXi xorg.libXmu freeglut
                 xorg.libXext xorg.libX11 xorg.libXv xorg.libXrandr zlib 
		 ncurses5
		 stdenv.cc
		 binutils
                ];
          multiPkgs = pkgs: with pkgs; [ zlib ];
          runScript = "bash";
          profile = ''
                  export CUDA_PATH=${pkgs.cudatoolkit}
                  # export LD_LIBRARY_PATH=${pkgs.linuxPackages.nvidia_x11}/lib
		  export EXTRA_LDFLAGS="-L/lib -L${pkgs.linuxPackages.nvidia_x11}/lib"
		  export EXTRA_CCFLAGS="-I/usr/include"
            '';
          };
in pkgs.stdenv.mkDerivation {
   name = "cuda-env-shell";
   nativeBuildInputs = [ fhs ];
   shellHook = "exec cuda-env";
}

• By making a nix-shell

cuda-shell.nix

{ pkgs ? import <nixpkgs> {} }:

pkgs.stdenv.mkDerivation {
   name = "cuda-env-shell";
   buildInputs = with pkgs;
                  [ git gitRepo gnupg autoconf curl
                    procps gnumake utillinux m4 gperf unzip
                    cudatoolkit linuxPackages.nvidia_x11
                    libGLU_combined
                    xorg.libXi xorg.libXmu freeglut
                    xorg.libXext xorg.libX11 xorg.libXv xorg.libXrandr zlib 
                    ncurses5 stdenv.cc binutils
                   ];
   shellHook = ''
      export CUDA_PATH=${pkgs.cudatoolkit}
      # export LD_LIBRARY_PATH=${pkgs.linuxPackages.nvidia_x11}/lib:${pkgs.ncurses5}/lib
		  export EXTRA_LDFLAGS="-L/lib -L${pkgs.linuxPackages.nvidia_x11}/lib"
		  export EXTRA_CCFLAGS="-I/usr/include"
   '';          
}

See also

• nixos-cuda-example
• nix-shell envs for Cuda
• CUDA setup on NixOS