nixos/system/services/xserver.nix

{ config, pkgs, ... }:
{
  services = {
    displayManager = {
      defaultSession = "none+i3";
      autoLogin.enable = true;
      autoLogin.user = "mbeno";

    };
    logind.extraConfig = "IdleAction=ignore";
    xserver = {
      exportConfiguration = true;
      enable = true;
      xkb.layout = "us,no";
      xkb.variant = "qwerty";
      xkb.options = "grp:lalt_lshift_toggle";
      desktopManager = {
        xterm.enable = false;
      };
      videoDrivers = [ "nvidia" ];
      deviceSection = ''
        Option "TearFree" "False"
        Option "VariableRefresh" "true"
      '';
      xrandrHeads = [
        {
          output = "DP-2";
          primary = true;
          monitorConfig = "
          Option \"TargetRefresh\" \"144\"
          Option \"Primary\" \"true\"
          Option \"PreferredMode\" \"2560x1440\"
          Option \"DPMS\" \"true\"
          ";
        }
        {
          output = "DP-0";
          primary = false;
          monitorConfig = "
          Option \"TargetRefresh\" \"144\"
          Option \"Primary\" \"false\"
          Option \"PreferredMode\" \"1920x1080\"
          ";
        }
      ];
      screenSection = ''
        Option         "metamodes" "DP-2: 2560x1440_144 +0+0, DP-0: 1920x1080_144 +2560+0"
      '';
      windowManager.i3 = {
        enable = true;
        extraPackages = with pkgs; [
          dmenu # application launcher most people use
          i3status # gives you the default i3 status bar
          i3lock
          #          i3lock #default i3 screen locker
          i3blocks # if you are planning on using i3blocks over i3status
          polybar
          rofi
          nitrogen
        ];
      };
    };
  };
}