My Nix configuration for my Lenovo X250

configuration.nix

# Edit this configuration file to define what should be installed on
# your system.  Help is available in the configuration.nix(5) man page
# and in the NixOS manual (accessible by running ‘nixos-help’).

{ config, pkgs, ... }:

{
  imports =
    [ # Include the results of the hardware scan.
      ./hardware-configuration.nix
    ];

  #allowDiscards = true;
  boot.initrd.luks.devices = [
    {
      name = "root";
      device = "/dev/sda3";
      preLVM = true;
    }
  ];

  # Use the gummiboot efi boot loader.
  # boot.loader.gummiboot.enable = true;
  boot.loader.efi.canTouchEfiVariables = true;
  boot.loader.grub.device = "/dev/sda";
  boot.loader.grub.memtest86.enable = true;

  boot.kernelParams = [ "libata.force=noncqtrim,noncq" ];

  # options snd_hda_intel enable=0,1
  # options libata.force=noncq
  boot.extraModprobeConfig = ''
    options snd_hda_intel index=1,0
  '';

  boot.kernelPackages = pkgs.linuxPackages_4_3;

  networking.hostName = "nixos"; # Define your hostname.
  networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.

  networking.extraHosts = ''
    127.0.0.1 nixos
    ::1 nixos
  '';

  # this is key for Lenovo x250
  powerManagement.scsiLinkPolicy = "max_performance";

  # Select internationalisation properties.
  # i18n = {
  #   consoleFont = "Lat2-Terminus16";
  #   consoleKeyMap = "us";
  #   defaultLocale = "en_US.UTF-8";
  # };

  # Set your time zone.
  time.timeZone = "Europe/Berlin";

  nixpkgs.config = {
    allowUnfree = true;
    firefox = {
      enableGoogleTalkPlugin = true;
      # enableAdobeFlash = true;
    };
  };

  # List packages installed in system profile. To search by name, run:
  # $ nix-env -qaP | grep wget
  environment.systemPackages = with pkgs; [
    bind
    wget
    vimHugeX
    rxvt_unicode
    binutils
    inetutils
    irssi
    ack
    jq
    sudo
    gitAndTools.gitFull
    firefoxWrapper
    chromium
    htop
    gnumake
    xpdf
    gcc
    zip
    unzip
    feh
    emacs
    pciutils
    xorg.xev

    update-resolv-conf

    haskellPackages.xmonad
    haskellPackages.xmobar
    dmenu
    xclip
    slock

    # fonts
    xfontsel
    xlsfonts
    dejavu_fonts
  ];

  # List services that you want to enable:

  # acpid
  services.acpid.enable = true;

  # Fingerprint reader
  # services.fprintd.enable = true;

  # MySQL
  services.mysql = {
    enable = true;
    package = pkgs.mysql;
    user = "aaronlevin";
    dataDir = "/home/aaronlevin/mysql/data";
  };

  # Enable CUPS to print documents.
  services.printing.enable = true;

  # Enable the OpenSSH daemon.
  services.openssh = {
    enable = true;
    extraConfig = ''
    '';
  };

  # Enable the X11 windowing system.
  services.xserver = {
    enable = true;
    windowManager.xmonad.enable = true;
    windowManager.xmonad.enableContribAndExtras = true;
    windowManager.default = "xmonad";
    desktopManager.xterm.enable = false;
    desktopManager.default = "none";

    synaptics = {
      enable = true;
      twoFingerScroll = true;
      palmDetect = true; horizontalScroll = true;
    };

    displayManager.sessionCommands = ''
      ${pkgs.xlibs.xset}/bin/xset r rate 200 60
      [[ -f ~/.Xresources ]] && ${pkgs.xlibs.xrdb}/bin/xrdb -merge ~/.Xresources
      xrandr --output eDP1 --primary
      xrandr --output DP1 --right-of eDP1
      feh --bg-scale /etc/images/haskell.png
    '';


    exportConfiguration = true;
    xkbOptions = "ctrl:swap_lalt_lctl, caps:super";
  };

  services.openvpn = {
    enable = true;
    servers = {
      client = {
        config = ''
          REDACTED
        '';
        up = '' 
          echo nameserver $nameserver | ${pkgs.openresolv}/sbin/resolvconf -m 0 -a $dev
          ${pkgs.update-resolv-conf}/libexec/openvpn/update-resolv-conf
        ''; 
        down = ''
          ${pkgs.openresolv}/bin/resolvconf -d $dev
          # REDACTED
          ${pkgs.update-resolv-conf}/libexec/openvpn/update-resolv-conf
        '';
       };
    };
  };

  virtualisation.docker = {
    enable = true;
  };
  
  security.sudo.wheelNeedsPassword = false;

  # Define a user account. Don't forget to set a password with ‘passwd’.
  users.extraUsers.aaronlevin = {
    isNormalUser = true;
    uid = 1000;
    extraGroups = ["wheel" "docker"];
  };

  fonts = {
    enableFontDir = true;
    enableGhostscriptFonts = true;
    fonts = [
      pkgs.corefonts
      pkgs.clearlyU
      pkgs.cm_unicode
      pkgs.dejavu_fonts
      pkgs.freefont_ttf
      pkgs.terminus_font
      pkgs.ttf_bitstream_vera
    ];
  };

  # The NixOS release to be compatible with for stateful data such as databases.
  system.stateVersion = "15.09";

}

hardware-configuration.nix

# Do not modify this file!  It was generated by ‘nixos-generate-config’
# and may be overwritten by future invocations.  Please make changes
# to /etc/nixos/configuration.nix instead.
{ config, lib, pkgs, ... }:

{
  imports =
    [ <nixpkgs/nixos/modules/installer/scan/not-detected.nix>
    ];

  boot.initrd.availableKernelModules = [ "xhci_pci" "ehci_pci" "ahci" "usbhid" "usb_storage" "fbcon"];
  # try forcing the loading of libata module.
  boot.initrd.kernelModules = [ "fbcon" "libata" ];

  boot.kernelModules = [ "kvm-intel" ];
  boot.extraModulePackages = [ ];

  fileSystems."/" =
    { device = "/dev/disk/by-uuid/bb6a6acb-055e-4d1f-9812-13c9d183bb6c";
      fsType = "ext4";
      options = "rw,relatime,nobarrier,data=ordered";
    };

  fileSystems."/boot" =
    { device = "/dev/disk/by-uuid/9cbf3855-bb29-4123-abd1-e08de2e39a36";
      fsType = "ext2";
    };

  swapDevices =
    [ { device = "/dev/disk/by-uuid/73bfe4e8-b4a6-433b-b152-73fd5702fcd8"; }
    ];

  nix.maxJobs = 4;
}