nixos-config/host/modules/gpu/nvidia.nix

{ config, pkgs-stable, lib, ... }: let
  primeCfg = config.host.nvidia.prime;
  isPrimeOffload = primeCfg.enable;
in {
  boot = {
    kernelParams = [ "nvidia-drm.modeset=1" ];
    initrd.kernelModules = lib.optionals isPrimeOffload [ "i915" ];
  };

  services.xserver.videoDrivers =
    if isPrimeOffload
    then [ "modesetting" "nvidia" ]
    else [ "nvidia" ];

  hardware = {
    graphics = {
      enable = true;
      enable32Bit = true;
      extraPackages = with pkgs-stable; [
        # nvidia-vaapi-driver
        intel-media-driver
        libvdpau-va-gl
      ];
      extraPackages32 = with pkgs-stable.pkgsi686Linux; [ nvidia-vaapi-driver intel-media-driver ];
    };

    nvidia = {
      modesetting.enable = true;
      powerManagement = {
        enable = true;
        finegrained = false;
      };
      open = false;
      nvidiaSettings = true;
      package = config.boot.kernelPackages.nvidiaPackages.stable;

      prime = lib.optionalAttrs isPrimeOffload {
        offload = {
          enable = true;
          enableOffloadCmd = true;
        };
        intelBusId = primeCfg.intelBusId;
        nvidiaBusId = primeCfg.nvidiaBusId;
      };
    };
  };

  environment.sessionVariables = {
    __GL_VRR_ALLOWED = 1;
    ELECTRON_OZONE_PLATFORM_HINT = "auto";
    NIXOS_OZONE_WL = 1;
  } // lib.optionalAttrs isPrimeOffload {
    LIBVA_DRIVER_NAME = "iHD";
  } // lib.optionalAttrs (!isPrimeOffload) {
    WLR_NO_HARDWARE_CURSORS = 1;
    WLR_DRM_NO_ATOMIC = 1;
    GBM_BACKEND = "nvidia-drm";
    LIBVA_DRIVER_NAME = "nvidia";
    __GLX_VENDOR_LIBRARY_NAME = "nvidia";
  };
}