Section: Maintenance Commands (8)
Updated: September 28, 2008
pwmconfig - tests the PWM outputs of sensors and configures fancontrol
will attempt to stop your fans, one at a time, for
approximately 5 seconds each. This may cause your processor
temperature to rise. Verify that all fans are running at normal speed
after this program has exited.
does its best to check that the fans are spinning when
they are supposed to, but due to the diversity of available
motherboards and fans, it shouldn't be blindly trusted. Always verify
It is strongly recommended to run pwmconfig at a time when there
is no significant system load, to minimize the risk of overheating.
searches your sensors for pulse width modulation (PWM)
controls, and tests each one to see if it controls a fan on
your motherboard. Note that many motherboards do not have PWM
circuitry installed, even if your sensor chip supports PWM.
When a connection is established between a PWM control and a fan,
pwmconfig can generate a detailed correlation, to show how a
given fan is responding to various PWM duty cycles.
Lastly, pwmconfig will enter in fancontrol configuration
mode (unless you decide to skip that part.) In this mode, you are
invited to enter several parameters which will determine how the
fancontrol daemon regulates the speed of one or more fans in
your system based on temperature measurements. In particular, you will
have the opportunity to establish mappings between fans and
temperature inputs, define the temperature range over which the speed
of the fan should be adjusted dynamically, the minimum speed at which
the fan should spin, etc. See fancontrol(8) for additional
The term "PWM" is used because most fan control systems in computers
are based on pulse width modulation. Some motherboards however use DC
variation instead. So, the term "PWM" should be seen as a generic term
for "fan speed control", regardless of the actual method used.
Marius Reiner <email@example.com>,
Jean Delvare <firstname.lastname@example.org>