ThinkPad Fan Control — KDE Tray Widget

A lightweight KDE system tray widget for monitoring CPU temperatures and manually controlling fan speed on ThinkPad laptops via the /proc/acpi/ibm/fan ACPI interface.

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Features

• Live CPU core temperatures and fan RPM in the tray tooltip
• Fan level control: levels 0–7, Auto, and Full-speed
• Frameless popup on left-click, stays resident on close
• Minimal footprint — no daemon, no config file

Requirements

• Linux with a ThinkPad exposing /proc/acpi/ibm/fan (most models do)
• lm-sensors (sudo apt install lm-sensors, then run sudo sensors-detect)
• python3-pyqt5

sudo apt install python3-pyqt5 lm-sensors

Privilege Setup

The widget writes to /proc/acpi/ibm/fan via sudo tee. Add a targeted sudoers rule so it can do so without a password prompt:

sudo visudo -f /etc/sudoers.d/thinkfan-tray

Add this line (replace yourusername):

yourusername ALL=(root) NOPASSWD: /usr/bin/tee /proc/acpi/ibm/fan

Verify tee is at /usr/bin/tee on your system (which tee). Only this one command is granted elevated access — the rest of the app runs as your normal user.

Usage

python3 fan-kde.py

• Left-click tray icon — toggle the control popup
• Hover tray icon — see current temps and fan RPM
• Right-click tray icon — Quit

Autostart on Login (KDE)

Create ~/.config/autostart/thinkfan-tray.desktop:

[Desktop Entry]
Type=Application
Name=ThinkFan Tray
Exec=python3 /path/to/fan-kde.py
Icon=temperature-symbolic
X-KDE-AutostartEnabled=true

Or add it via System Settings → Autostart → Add Script.

Notes

• Fan level auto returns control to the BIOS/EC firmware
• Fan level full-speed is loud — useful for sustained load or thermal emergencies
• Tested on a ThinkPad with the thinkpad_acpi kernel module loaded