fancontrol-gui

A GUI for fancontrol, the fan-control daemon shipped with lm-sensors. It lets you read and adjust fan speeds and watch temperatures from a simple desktop application.

This is the Qt 6 / KDE Frameworks 6 port (see Status).

The app talks to the fancontrol daemon in two ways:

• It generates a fancontrol configuration file from your hardware and writes it through the KDE KAuth framework.
• It controls the fancontrol systemd service (start/stop/restart, apply-and-restart) through D-Bus via systemd-communicator.

The Qt6 build uses a dedicated systemd communicator based on systemd's D-Bus API, so it works on modern distributions without relying on pkexec or the ability to run the helper with root privileges.

Features

• Sensor overview — live temperature chart and per-sensor values on the Sensors tab.
• Fan control curves — build PWM fan curves point by point. Drag the start and maximum anchors and the intermediate waypoints, add or remove points, and start from the Silent, Cool, Balanced or Performance presets.
• Autotune — measure the fan's real start and stop values. The test streams live phase feedback (finding the lowest speed, start speed, stop speed) with an abort button, and only applies what you confirm.
• Editable fan names — rename any fan inline; names are persisted and used everywhere in the UI.
• Temperature & PWM history — a live timeline plus the PWM duty cycle for the selected fan.
• Profiles — apply, create, save to, rename, duplicate and delete named profiles, with confirmation for destructive actions. Profiles can be imported from and exported to *.conf files.
• Configuration file view — the Configfile tab shows the generated file as Raw text, a structured Table (per-fan thresholds and PWM levels), and a Changes diff of pending edits. It validates the configuration and flags invalid combinations (e.g. MINTEMP ≥ MAXTEMP, MINSTOP > MAXPWM). A configuration can be imported from a URL or pasted directly, then reviewed before it is applied.
• Temperature alarm — enable a threshold; the app shows an inline alarm banner and raises a desktop notification (KNotification) when a sensor exceeds it, listing the offending sensor and current value.
• Follows the system theme — light and dark mode track the desktop setting live, without restarting the app.
• Tray integration — tray icon, start minimized, all optional.
• Plasmoid & KCM — optional KDE Plasma widget and system-settings module.

Screenshots

Each screenshot shows dark mode on the left and light mode on the right.

Sensors

Fans — fan curve

Fans — temperature & PWM

Configfile — table

Configfile — raw and changes

Settings

Status

• 2026 — ported from Qt5/KF5 to Qt6 / KDE Frameworks 6. Build, install and the bundled unit tests are verified against current KF6 on up-to-date distributions; continuous integration builds and runs the test suite on every push.
• Recent UX work includes the tabbed Fans layout, the structured Configfile view with validation and diffing, full profile management, an autotune rework, editable fan names, live system dark/light following, and a themed application icon.

Tested on

The current Qt6/KF6 build is developed and verified on:

• OS: Debian GNU/Linux 13 (trixie), kernel 6.18
• Toolkit: Qt 6.8.2 and KDE Frameworks 6.13
• Desktop: GNOME (X11 and Wayland) — light/dark following was verified with both the GTK color-scheme setting and the Plasma colour scheme
• Hardware: AMD Radeon RX 6900 XT fan (amdgpu) and a Nuvoton NCT6687D controller (nct6687)

Distribution packaging known to work is listed under Build requirements. Continuous integration builds the project and runs the unit tests on every push.

Build requirements

• Qt6: Base/Core, Widgets, Gui, QML, Quick, QuickControls2
• KF6: I18n, Auth, Config, Package, Declarative, CoreAddons, DBusAddons, Extra-Cmake-Modules, Notifications
• Other: a C++ compiler, Gettext, CMake

Additional runtime requirements

• Qt6: Quick 2.15, QuickControls2 2.15, QuickLayouts 2.15, QuickDialogs
• KF6: Kirigami2 2.14

Additional requirements for KCM

• KF6: KCMUtils

Additional requirements for plasmoid

• KF6: Plasma

Debian/Ubuntu

sudo apt-get install ca-certificates git build-essential cmake gcc g++ \
  libkf6config-dev libkf6auth-dev libkf6package-dev libkf6declarative-dev \
  libkf6coreaddons-dev libkf6dbusaddons-dev libkf6kcmutils-dev libkf6i18n-dev \
  libkf6plasma-dev libqt6core6 libqt6widgets6 libqt6gui6 libqt6qml6 \
  extra-cmake-modules qt6-base-dev libkf6notifications-dev \
  qml6-module-org-kde-kirigami qml6-module-qtquick-dialogs \
  qml6-module-qtquick-controls qml6-module-qtquick-layouts \
  qml6-module-qt-labs-settings qml6-module-qt-labs-folderlistmodel \
  cmake build-essential gettext

Note: tested on Ubuntu 24.04 LTS and Debian 12.

Fedora

sudo dnf install git gcc g++ cmake kf6-ki18n-devel kf6-kauth-devel \
  kf6-kconfig-devel kf6-kpackage-devel kf6-kcoreaddons-devel \
  kf6-kdbusaddons-devel extra-cmake-modules kf6-knotifications-devel \
  qt6-qtquickcontrols2-devel kf6-kconfigwidgets-devel kf6-kcmutils-devel \
  kf6-plasma-devel cmake gettext qt6-qtbase-devel gcc-c++ \
  kf6-kdeclarative-devel qt6-qtquickcontrols qt6-qtquickcontrols2

Note: tested on Fedora 40.

Install

git clone https://github.com/tmiland/fancontrol-gui.git
cd fancontrol-gui
mkdir build
cd build
cmake .. -DCMAKE_INSTALL_PREFIX=/usr -DBUILD_KCM=on -DBUILD_PLASMOID=on
make -j
sudo make install

If you run the application from the build tree instead of installing it, point the QML engine at the module and package in the build/install tree, or simply install it — the app loads its QML from the installed module.

Build options

Option	Default	Description
-DNO_SYSTEMD=true	off	Build without systemd support.
-DBUILD_KCM=on	off	Also build the KDE Settings module. Only available when systemd support is enabled.
-DBUILD_PLASMOID=on	off	Also build the KDE Plasma plasmoid.
-DINSTALL_POLKIT=true	off	Install a polkit rules file that lets members of a group edit the config and manage the service without prompting.
-DPOLKIT_GROUP_NAME=...	fancontrol	Group allowed by the polkit rules file.
-DSTANDARD_SERVICE_NAME=...	standard	Name of the fancontrol service.
-DSTANDARD_CONFIG_FILE=...	standard	Path of the fancontrol config file.
-DKDE_INSTALL_USE_QT_SYS_PATHS=true	off	Use /usr/lib/qt/qml when your distribution places QML there instead of /usr/lib/qml.

KAuth notes: KAuth does not currently support install prefixes other than the one KAuth itself was installed into. To use another prefix, run the application as root (or as a user with the required privileges) to avoid the KAuth helper. To avoid authorizing every use of the helper, build with -DINSTALL_POLKIT=true; this installs a polkit rules file allowing members of the group fancontrol to edit the config file and control the service. The group can be changed with -DPOLKIT_GROUP_NAME.

Theming

The application follows the desktop's light/dark preference automatically and updates live when it changes. On Plasma the reported colour scheme is used; on GTK-based desktops (e.g. GNOME) the org.gnome.desktop.interface color-scheme setting is consulted. Set FANCONTROL_COLOR_SCHEME=dark or light to override the detection.

Running the tests

cd build
ctest --output-on-failure

The suite (hwmon, fan, pwmfan, temp and config-loader tests) is built when BUILD_TESTING is enabled (the default) and is run by CI on every push.

Uninstall

cd fancontrol-gui/build
sudo make uninstall

License

fancontrol-gui is released under the GNU Lesser General Public License (version 2 or later). See COPYING for details.