#+title: Disable the IBM TrackPoint
#+setupfile: ../../headers

* Disable the IBM TrackPoint
My ThinkPads come with IBM’s TrackPoint, the little red nub sitting
between the =G=, =H= and =B= keys. I don’t want it active, though, it has a
drift and I cannot fix it unless I change my keyboard. Thus, this
module exposes a way to turn it off. Here’s the skeleton of the
=nixos.disable-ibm-trackpoint= module.
#+begin_src nix :tangle yes
{
  flake.modules.nixos.disable-ibm-trackpoint = {
    <<udev-rule>>
  };
}
#+end_src

** Disabling the TrackPoint
The TrackPoint shows up to the input stack as a regular pointer
device, so to disable it I can’t simply blacklist a driver — libinput
and friends would still pick it up through =evdev=. Instead, I match it
by its device name and clear the =ID_INPUT=, =ID_INPUT_MOUSE= and
=ID_INPUT_POINTINGSTICK= udev properties on it, which tells the input
stack to simply ignore the device as a pointing device.
#+name: udev-rule
#+begin_src nix
services.udev.extraRules = ''
  ATTRS{name}=="*TPPS/2 IBM TrackPoint", ENV{ID_INPUT}="", ENV{ID_INPUT_MOUSE}="", ENV{ID_INPUT_POINTINGSTICK}=""
'';
#+end_src