#+title: Corne Keyboard
#+setupfile: ../../headers

* Corne Keyboard
I use a Corne (=crkbd=), a small split ergonomic keyboard, flashed with
[[https://get.vial.today/][Vial]], a QMK-based firmware that lets me remap keys live from a GUI
instead of having to reflash the keyboard every time I want to tweak
my layout. Here’s the skeleton of the =nixos.corne= module.
#+begin_src nix :tangle yes
{
  flake.modules.nixos.corne = {
    <<udev-rule>>
  };
}
#+end_src

** Granting HID Access
By default, the =hidraw= device nodes created for the keyboard are only
accessible to root, which means Vial can’t talk to it without running
as root too. Instead, I add a =udev= rule matching my keyboard’s Vial
identifier (the part after =vial:= is the keyboard’s unique unlock ID,
burned into its firmware) and grant the =users= group read/write access
to it, tagging it for =uaccess= / =udev-acl= so it’s also picked up by the
logged-in session’s ACLs.
#+name: udev-rule
#+begin_src nix
services.udev = {
  extraRules = ''
    KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{serial}=="*vial:f64c2b3c*", MODE="0660", GROUP="users", TAG+="uaccess", TAG+="udev-acl"
  '';
};
#+end_src