configuration.nix

{
  # …
  
  services.xserver = {
    enable = true;
    layout = "us";
    displayManager.lightdm.enable = true;
    displayManager.job.logToJournal = false;
    # displayManager.job.logToFile = lib.mkForce false;
    monitorSection = ''
      # Set the right DPI. Screen is 344x193 mm.
      DisplaySize 344 193
    '';
    libinput.enable = true;
  };

  # …
}

xprofile.sh

if [[ -e "$HOME/.profile" ]]; then
  . "$HOME/.profile"
fi

# If there are any running services from a previous session.
# Need to run this in xprofile because the NixOS xsession
# script starts up graphical-session.target.
systemctl --user stop graphical-session.target graphical-session-pre.target

systemctl --user import-environment DBUS_SESSION_BUS_ADDRESS
systemctl --user import-environment DISPLAY
systemctl --user import-environment SSH_AUTH_SOCK
systemctl --user import-environment XAUTHORITY
systemctl --user import-environment XDG_DATA_DIRS
systemctl --user import-environment XDG_RUNTIME_DIR
systemctl --user import-environment XDG_SESSION_ID



export HM_XPROFILE_SOURCED=1

xsession.sh

if [[ ! -v HM_XPROFILE_SOURCED ]]; then
  . ~/.xprofile
fi
unset HM_XPROFILE_SOURCED

systemctl --user start hm-graphical-session.target

# Set a default pointer.
xsetroot -cursor_name left_ptr

# Turn off beeps.
xset -b

# Quicker blanking of screen.
xset dpms 120 360 800


/nix/store/ni1rwdykbc085lja4ziqw72mw2sg7hz7-xmonad-with-packages/bin/xmonad

systemctl --user stop graphical-session.target
systemctl --user stop graphical-session-pre.target

# Wait until the units actually stop.
while [[ -n "$(systemctl --user --no-legend --state=deactivating list-units)" ]]; do
  sleep 0.5
done