thinkfan(1) A simple fan control program


[ -hnqzDd ] [ -b BIAS ] [ -c CONFIG ] [ -s SECONDS ] [ -p [DELAY] ]


Thinkfan sets the fan speed according to temperature limits preconfigured in /etc/thinkfan.conf. It can read temperatures from three possible sources:
Which is provided by the thinkpad_acpi kernel module,
Which may be provided by any hwmon drivers, and
S.M.A.R.T. (since 0.9)
Which reads the temperature directly from the hard disk using libatasmart.

Note that since 0.9 you can use any sensors of these three types at the same time. To allow that, the configuration keywords have been changed. The sensor keyword has been deprecated in favor of the new keywords tp_thermal, hwmon and atasmart which mark the following path as a legacy thinkpad_acpi thermal file, sysfs hwmon file, or a hard disk device file, respectively.

The fan can be /proc/acpi/ibm/fan or some PWM file in /sys/class/hwmon. Note that the fan config keyword is deprecated as well. Instead, you should use tp_fan for a legacy thinkpad_acpi fan file or pwm_fan for a sysfs PWM file.

See the README file and the example configurations for details on these changes.

WARNING: This program does only very basic sanity checking on the
configuration. That means that you can set your temperature limits as insane as you like.

There are two general modes of operation:


In complex mode, temperature limits are defined for each sensor thinkfan knows about. Setting suitable limits for each sensor in your system will probably require a bit of experimentation and good knowledge about your hardware, but it's the safest way of keeping each component within its specified temperature range. See for details on which sensor measures what temperature in a Thinkpad. On other systems you'll have to find out on your own. See the example configs to learn about the syntax.


In simple mode, Thinkfan uses only the highest temperature found in the system. That may be dangerous, e.g. for hard disks. That's why you should provide a correction value (i.e. add 10-15 °C) for the sensor that has the temperature of your hard disk (or battery...). See the example config files for details about that.


Some example configurations are provided with the source package. For detailed explanations please read the README file. If you installed thinkfan from a distribution package, you may find them under /usr/share/doc or wherever your package manager puts documentation.


Show a short help message
Maximum seconds between temperature updates (default: 5)
Floating point number (-10 to 30) to control rising temperature exaggeration. If the temperature increases by more than 2 °C during one cycle, this number is used to calculate a bias, which is added to the current highest temperature seen in the system:

 current_tmax = current_tmax + delta_t * BIAS / 10

This means that negative numbers can be used to even out short and sudden temperature spikes like those seen on some on-DIE sensors. Use DANGEROUS mode to remove the -10 to +30 limit. Note that you can't have a space between -b and a negative argument, because otherwise getopt will interpret things like -10 as an option and fail (i.e. write "-b-10" instead of "-b -10").

Default is 15.0

Load a different configuration file (default: /etc/thinkfan.conf)
Do not become a daemon and log to terminal instead of syslog
Be quiet (no status info on terminal)
Assume we don't have to worry about resuming from standby when using the sysfs interface (see README!)
Use the pulsing-fan workaround (for older Thinkpads). Takes an optional floating-point argument (0-10s) as depulsing duration. Default 0.5s.
Do not read temperature from sleeping disks. Instead, 0 °C is used as that disk's temperature. This is needed if reading the temperature causes your disk to wake up unnecessarily. Note: This option is only available if thinkfan was built with -D USE_ATASMART.
DANGEROUS mode: Disable all sanity checks. May damage your hardware!!


SIGINT and SIGTERM simply interrupt operation and should cause thinkfan to terminate cleanly.

SIGHUP makes thinkfan reload its config. If there's any problem with the new config, we keep the old one.

SIGUSR1 causes thinkfan to dump all currently known temperatures either to syslog, or to the console (if running with the -n option).


If you have any problems with thinkfan, please go to the help forum at

There's a bugtracker at