ChucK HID input on Debian
=========================

ChucK's Hid class can read joysticks/gamepads, keyboards, and mice.
Examples are in /usr/share/doc/chuck-data/examples/hid/ (package
chuck-data).

Joysticks and gamepads
----------------------

These work out of the box.  ChucK reads them via /dev/input/js*, which
Debian makes readable by all users.

Keyboards and mice
------------------

ChucK reads keyboards and mice via /dev/input/event*.  These are
readable only by root and group "input", so by default this fails with:

  hid: please verify you have read permissions to input device ...

This restriction is deliberate.  Reading a keyboard's event device
captures every keystroke on the system regardless of which window has
focus, including passwords typed into a lock screen or sudo.  That is
also why you should NOT add yourself to the "input" group: it lets any
program you run log all your keystrokes.

Alternatives, safest first:

 1. For keyboard input, use ChucK's KBHit class instead of Hid.  It reads
    keys typed into the terminal running chuck, needs no permissions,
    and cannot see input to other windows.  See the examples in
    /usr/share/doc/chuck-data/examples/hid/kbhit/.

 2. To use a keyboard-like or mouse-like device as a controller, use a
    separate, dedicated device (a USB numeric keypad, a spare mouse, a
    foot pedal, ...) and grant access to that one device only.  Find its
    USB vendor and product IDs with lsusb (shown as ID vvvv:pppp), then
    create /etc/udev/rules.d/70-chuck-hid.rules containing, e.g.:

      SUBSYSTEM=="input", KERNEL=="event*", ATTRS{idVendor}=="vvvv", ATTRS{idProduct}=="pppp", TAG+="uaccess"

    The file name must sort before 73-seat-late.rules for the uaccess
    tag to take effect.  Then run

      sudo udevadm control --reload
      sudo udevadm trigger

    or replug the device.  systemd-logind will then give the user at the
    active local seat (and only that user) read access to that device.

    Do not do this for the keyboard you normally type on, as that
    re-opens the keystroke logging hole described above.

 -- Barak A. Pearlmutter <bap@debian.org>  Thu, 15 Oct 2026 12:00:00 +0100