Problem · Install · How it works · Config · Hardware · Troubleshooting · Design

On modern Linux ThinkPads — Yoga 370, T470, X270, X1 Carbon Gen 5 and most of the 2017-onward Elantech-digitizer lineup — the three TrackPoint buttons below the spacebar share an input device with the red dot (pointing stick) itself. Disable the pointer (BIOS toggle, inhibited=1, xinput disable) and you lose the buttons too. On Wayland, the classic Coordinate Transformation Matrix escape hatch is gone.

Every forum answer, every Stack Overflow thread, every dotfile gist ignores this. Here's the receipt:

The only fix that actually works is to grab the device at the kernel boundary and drop the X/Y motion while re-emitting the button events through a fresh uinput pointer. 30 lines of Python. That's it.

git clone https://github.com/Jok0ne/zo-reddot.git
cd zo-reddot
./install.sh

The installer:

• installs python3-evdev (supports dnf / apt-get / pacman),
• copies zo-reddot.py to /usr/local/bin/ and the unit to /etc/systemd/system/,
• enables and starts zo-reddot.service.

Root is required — exclusive grab on an input device and writing to /dev/uinput are privileged operations.

systemctl status zo-reddot
journalctl -u zo-reddot -f

Expected log line:

zo-reddot: grabbed + uinput up — buttons only, motion dropped

Nudge the red dot: nothing. Click any of the three buttons under the spacebar: normal left / middle / right click.

  ┌────────────────────────┐
  │    TrackPoint device   │  /dev/input/event4
  │   (Elantech ISA PS/2)  │  emits:  BTN_LEFT/RIGHT/MIDDLE  +  EV_REL(X,Y)
  └────────────┬───────────┘
               │  device.grab() — exclusive read
               ▼
  ┌────────────────────────┐
  │       zo-reddot        │  forward:  BTN_LEFT/RIGHT/MIDDLE
  │     event  filter      │  drop:     EV_REL X/Y, scroll emulation
  └────────────┬───────────┘
               │  UInput.write_event() + syn()
               ▼
  ┌────────────────────────┐
  │ "TrackPoint Buttons    │  new /dev/input/eventN
  │  Only" (uinput device) │  advertises only BTN_LEFT/RIGHT/MIDDLE
  └────────────┬───────────┘
               │
               ▼
  ┌────────────────────────┐
  │    libinput +          │  buttons integrate normally,
  │    Wayland / X11       │  no pointer motion
  └────────────────────────┘

libinput and the desktop environment see the new uinput device as a normal button-only pointer and integrate it automatically. The pointing-stick itself has no visible consumer anymore, so nudging it does nothing.

Service survives reboots. Uninstall releases the device cleanly and restores the original behaviour.

The service matches the input device by exact name. Default:

TRACKPOINT_NAME=ETPS/2 Elantech TrackPoint

If your device has a different name — find it with cat /proc/bus/input/devices or sudo libinput list-devices — set TRACKPOINT_NAME in /etc/systemd/system/zo-reddot.service:

Environment=TRACKPOINT_NAME=TPPS/2 Elan TrackPoint

Then:

sudo systemctl daemon-reload
sudo systemctl restart zo-reddot

./install.sh uninstall

Stops and disables the service, removes the script and unit file. Original TrackPoint behaviour (pointer + buttons) is back immediately.

If you run it successfully on other hardware, a PR adding to this list is welcome.

• Touchpad — separate input device.
• External USB / Bluetooth mice.
• Keyboard.
• Plasma / GNOME pointer-speed settings on every other pointer.

qdbus-qt6 org.kde.KWin /KWin reconfigure

journalctl -u zo-reddot -n 20

cat /proc/bus/input/devices | grep -iE "trackpoint|pointing"

sudo systemctl stop zo-reddot
sudo /usr/bin/python3 /usr/local/bin/zo-reddot.py

Both work. ZO-REDdot exists because:

• Zero compilation. One Python file, done.
• Readable source — ~30 lines you can audit before running as root.
• Single dependency (python3-evdev) that every distro packages.
• One process, one syscall loop — no cascading dependency services.

If you need maximum efficiency, a compiled C equivalent saves ~15 MB of Python RSS. For a background daemon on a modern laptop, that tradeoff is usually fine.

EVIOCGRAB (exclusive device grab) and writing to /dev/uinput both require CAP_SYS_ADMIN or explicit input-group access plus uaccess. We could drop to a dedicated user with those capabilities, but root + SupplementaryGroups=input is clearer and the attack surface is ~30 lines of code.

X11's Coordinate Transformation Matrix zeros out motion at the server level and leaves buttons alone — elegant, but bound to X11. Wayland has no equivalent primitive exposed to userspace. Kernel-level grab + uinput re-emit works on both, with the same latency as any other input device.

GPL-3.0-or-later — see LICENSE.

Copyright © 2026 Zerone. If you redistribute this — modified or not — recipients must keep the same freedoms you received: attribution preserved, source available, changes released under the same terms.

SPDX-License-Identifier: GPL-3.0-or-later