Difference between revisions of "Fan speed control"

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   # systemctl enable dell-bios-fan-control
   # systemctl enable dell-bios-fan-control
   # systemctl start dell-bios-fan-control
   # systemctl start dell-bios-fan-control
== ThinkPad laptops ==
== ThinkPad laptops ==

Revision as of 18:12, 29 June 2019

Fan control can bring various benefits to your system, such as quieter working system and power saving by completely stopping fans on low CPU load.

Warning: Configuring or completely stopping fans on high system load might result in permanently damaged hardware.


Note: Laptop users should be aware about how cooling system works in their hardware. Some laptops have single fan for both CPU and GPU and cools both at the same time. Some laptops have two fans for CPU and GPU, but the first fan cools down CPU and GPU at the same time, while the other one cools CPU only. In some cases, you will not be able to use Fancontrol script due to incompatible cooling architecture (e.g. one fan for both GPU and CPU). Here is some more information about this topic.

There are multiple working solutions for fan control for both desktops and notebooks. Depending on your needs:

Fancontrol (lm-sensors)

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: Instructions are not clear and organized in overall. (Discuss in Talk:Fan speed control#)

fancontrol is a part of lm_sensors, which can be used to control the speed of CPU/case fans.

Support for newer motherboards may not yet be in the Linux kernel. Check the official lm-sensors devices table to see if experimental drivers are available for such motherboards.

It is recommended not to use lm_sensors.service to load the needed modules for fancontrol. Instead, manually place them in /etc/modules-load.d/load_these.conf since the order in which these modules are loaded dictate the order in which the needed symlinks for hwmon get created. In other words, using the lm_sensors.service causes inconsistencies boot-to-boot which will render the configuration file for fan control worthless for a consistency point of view. To avoid this problem:

In /etc/conf.d/lm_sensors you find the modules. If not there, run as root sensors-detect accepting the defaults. In the modules-load.d file place one module name per line. Specifying them like this will create a reproducible order. Another alternative is to use absolute device names in the configuration file.[1]


After checking that lm_sensors is properly setup, run sensors.

$ sensors
Adapter: ISA adapter
Core 0:      +29.0°C  (high = +76.0°C, crit = +100.0°C)  
Adapter: ISA adapter
Vcc:         +1.14 V  (min =  +0.00 V, max =  +4.08 V)   
VTT:         +2.08 V  (min =  +0.00 V, max =  +4.08 V)   
+3.3V:       +3.33 V  (min =  +0.00 V, max =  +4.08 V)   
NB Vcore:    +0.03 V  (min =  +0.00 V, max =  +4.08 V)   
VDRAM:       +2.13 V  (min =  +0.00 V, max =  +4.08 V)   
fan1:        690 RPM  (min =   10 RPM)
temp1:       +37.5°C  (low  = +129.5°C, high = +129.5°C)  sensor = thermistor
temp2:       +25.0°C  (low  = +127.0°C, high = +127.0°C)  sensor = thermal diode
Note: If the output does not display an RPM value for the CPU fan, one may need to #increase the fan divisor for sensors. If the fan speed is shown and higher than 0, this is fine.


Note: Advanced users may want to skip this section and write /etc/fancontrol on their own, which also saves them from hearing all of the fans at full speed.

Once sensors are properly configured, use pwmconfig to test and configure fan speed control. The default configuration options should create /etc/fancontrol configuration file:

# pwmconfig


Note: On several systems, the included script may report errors as it tries to calibrate fans to the respective pulse-width modulation (PWM). Users may safely ignore these errors. The problem is that the script does not wait long enough before ramping up or down the PWM.

Users wishing more control may need to tweak the generated configuration. Here is a sample configuration file:

DEVPATH=hwmon0=devices/platform/coretemp.0 hwmon2=devices/platform/w83627ehf.656
DEVNAME=hwmon0=coretemp hwmon2=w83627dhg
FCFANS= hwmon0/device/pwm1=hwmon0/device/fan1_input
  • INTERVAL: how often the daemon should poll CPU temps and adjust fan speeds. INTERVAL is in seconds.

The rest of the configuration file is split into (at least) two values per configuration option. Each configuration option first points to a PWM device which is written to which sets the fan speed. The second "field" is the actual value to set. This allows monitoring and controlling multiple fans and temperatures.

  • FCTEMPS: The temperature input device to read for CPU temperature. The above example corresponds to /sys/class/hwmon/hwmon0/device/temp1_input.
  • FCFANS: The current fan speed, which can be read (like the temperature) in /sys/class/hwmon/hwmon0/device/fan1_input
  • MINTEMP: The temperature (°C) at which to SHUT OFF the CPU fan. Efficient CPUs often will not need a fan while idling. Be sure to set this to a temperature that you know is safe. Setting this to 0 is not recommended and may ruin your hardware!
  • MAXTEMP: The temperature (°C) at which to spin the fan at its MAXIMUM speed. This should be probably be set to perhaps 10 or 20 degrees (°C) below your CPU's critical/shutdown temperature. Setting it closer to MINTEMP will result in higher fan speeds overall.
  • MINSTOP: The PWM value at which your fan stops spinning. Each fan is a little different. Power tweakers can echo different values (between 0 and 255) to /sys/class/hwmon/hwmon0/device/pwm1 and then watch the CPU fan. When the CPU fan stops, use this value.
  • MINSTART: The PWM value at which your fan starts to spin again. This is often a higher value than MINSTOP as more voltage is required to overcome inertia.

There are also two settings fancontrol needs to verify the configuration file is still up to date. The lines start with the setting name and an equality sign, followed by groups of hwmon-class-device=setting, separated by spaces. You need to specify each setting for each hwmon class device you use anywhere in the config, or fancontrol will not work.

  • DEVPATH: Sets the physical device. You can determine this by executing the command
readlink -f /sys/class/hwmon/[your-hwmon-device]/device | sed -e 's/^\/sys\///'
  • DEVNAME: Sets the name of the device. Try:
$ sed -e 's/[[:space:]=]/_/g' /sys/class/hwmon/[your-hwmon-device]/device/name
Tip: Use MAXPWM and MINPWM options that limit fan speed range. See fancontrol manual page for details.
Tip: Not only the DEVPATH may change on reboot due to different timing of module loading, but also e.g. the temperature sensor paths (hwmon0/device/temp1_input becomes hwmon0/temp1_input). This usually happens on a kernel update. Check the system log to find out which is the troublemaker:
# systemctl status fancontrol.service
and correct your config file accordingly.


Note: Upon upgrading/changing the kernel, running fancontrol may result in an error regarding changed device paths. This issue may be fixed by running sensors-detect again and restarting the system.

Try to run fancontrol:

# /usr/bin/fancontrol

A properly configured setup will not error out and will take control of system fans. Users should hear system fans slowing shortly after executing this command.

To enable starting fancontrol automatically on every boot, enable fancontrol.service.

For an unofficial GUI install fancontrol-guiAUR or fancontrol-kcmAUR.


NBFC is a cross-platform fan control solution for notebooks. It comes with a powerful configuration system, which allows to adjust it to many different notebook models, including some of the latest ones.


NBFC can be installed as nbfcAUR or nbfc-gitAUR. Also start and enable nbfc.service.


NBFC comes with pre-made profiles. You can find them in /opt/nbfc/Configs/ directory. When applying them, use exact profile name without extension (e.g. some profile.xml becomes "some profile").

Check if there is anything NBFC can recommend:

$ nbfc config -r

If there is at least one model, try to apply this profile and see how fan speeds are being handled. For example:

$ nbfc config -a "Asus Zenbook UX430UA"
Note: If you are getting File Descriptor does not support writing, delete StagWare.Plugins.ECSysLinux.dll [2] and restart nbfc.service:
# mv /opt/nbfc/Plugins/StagWare.Plugins.ECSysLinux.dll /opt/nbfc/Plugins/StagWare.Plugins.ECSysLinux.dll.old

If above solution did not help, try appending ec_sys.write_support=1 to kernel parameters.

If there are no recommended models, go to NBFC git repository or /opt/nbfc/Configs/ and check if there are any similar models available from the same manufacturer. For example, on Asus Zenbook UX430UQ, the configuration Asus Zenbook UX430UA did not work well (fans completelly stopped all the time), but Asus Zenbook UX410UQ worked fantastically.

Run nbfc to see all options. More information about configuration is available at upstream wiki.

Dell laptops

i8kutils is a daemon to configure fan speed according to CPU temperatures on some Dell Inspiron and Latitude laptops. It uses the /proc/i8k interface provided by the dell_smm_hwmon driver (formerly i8k). Results will vary depending on the exact model of laptop.

Warning: i8kutils BIOS system calls stop the kernel for a moment on some systems (confirmed on Dell 9560), this can lead to side effects like audio dropouts, see https://bugzilla.kernel.org/show_bug.cgi?id=201097


i8kutilsAUR is the main package to control fan speed. Additionally, you might want to install these:

  • acpi - must be installed to use i8kmon.
  • tcl - must be installed in order to run i8kmon as a background service (using the --daemon option).
  • tk - must be installed together with tcl to run as X11 desktop applet.
  • dell-bios-fan-control-gitAUR - recommended if your BIOS overrides fan control


By default, i8kmon only monitors the CPU temperature and fan speed passively. To enable its fan speed control, either run it with the --auto option or enable the option permanently in /etc/i8kutils/i8kmon.conf:

set config(auto)       1

The temperature points at which the fan changes speed can be adjusted in the same configuration file. Only three fans speeds are supported (high, low, and off). Look for a section similar to the following:

set config(0)  {{0 0}  -1  55  -1  55}
set config(1)  {{1 1}  45  75  45  75}
set config(2)  {{2 2}  65 128  65 128}

This example starts the fan at low speed when the CPU temperature reaches 55 °C, switching to high speed at 75 °C. The fan will switch back to low speed once the temperature drops to 65 °C, and turns off completely at 45 °C.

Installation as a service

i8kmon can be started automatically as a systemd service:

 # systemctl enable i8kmon
 # systemctl start i8kmon

BIOS overriding fan control

Some newer laptops have BIOS fan control in place which will override the OS level fan control. To test if this the case, run i8kmon with verbose mode in a command line, make sure the CPU is idle, then see if the fan is turned off or turned down accordingly.

If the BIOS fan control is in place, you can try using dell-bios-fan-control-gitAUR:

Warning: turning off BIOS fan control could result in damage to your hardware. Make sure you have i8kmon properly set up beforehand, or leave the CPU idle while you test this program

To enable BIOS fan control:

 # dell-bios-fan-control 1

To disable BIOS fan control:

 # dell-bios-fan-control 0

To automatically disable BIOS fan control via systemd:

 # systemctl enable dell-bios-fan-control
 # systemctl start dell-bios-fan-control

ThinkPad laptops

The embedded controller (EC) regulates fan speed. However, in order to take control over it, add fan_control=1 to your kernel parameters.

Current fan control daemons available in the AUR are simpfand-gitAUR and thinkfanAUR (recommended).


Install thinkfanAUR or thinkfan-gitAUR. Optionally, but recommended, install lm_sensors. Then have a look at the files:

# pacman -Ql thinkfan

Note that the thinkfan package installs /usr/lib/modprobe.d/thinkpad_acpi.conf, which contains

options thinkpad_acpi fan_control=1

So fan control is enabled by default. Alternatively, you can enable fan control as follows:

$ echo "options thinkpad_acpi fan_control=1" > /etc/modprobe.d/thinkfan.conf

Now, load the module:

$ su
# modprobe thinkpad_acpi
# cat /proc/acpi/ibm/fan

You should see that the fan level is "auto" by default, but you can echo a level command to the same file to control the fan speed manually. The thinkfan daemon will do this automatically.

Set thinkfan to run at startup by editing /etc/default/thinkfan and adding the following line:


Finally, enable the thinkfan systemd service:

$ systemctl enable thinkfan

To configure the temperature thresholds, you will need to copy one of the example config files (e.g. /usr/share/doc/thinkfan/examples/thinkfan.conf.simple) to /etc/thinkfan.conf, and modify to taste. This file specifies which sensors to read, and which interface to use to control the fan. Some systems have /proc/acpi/ibm/fan and /proc/acpi/ibm/thermal available; on others, you will need to specify something like:

hwmon /sys/devices/virtual/thermal/thermal_zone0/temp

to use generic hwmon sensors instead of thinkpad-specific ones.


You can test your configuration first by running thinkfan manually (as root):

# thinkfan -n

and see how it reacts to the load level of whatever other programs you have running.

When you have it configured correctly, start/enable thinkfan.service.

Asus laptops

This topic will cover drivers configuration on Asus laptops for Fancontrol (lm-sensors).

Kernel modules

In configuration files, we are going to use full paths to sysfs files (e.g. /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[:print:]]*/pwm1). This is because hwmon1 might change to any other number after reboot. Fancontrol (lm-sensors) is written in Bash, so using these paths in configuration file is completely acceptable. You can find complete /etc/fancontrol configuration file examples at ASUS N550JV#Fan control.


asus-nb-wmi is a kernel module, which is included in the Linux kernel and is loaded automatically on Asus laptops. It will only allow to control a single fan and if there is a second fan you will not have any controls over it. Note that blacklisting this module will prevent keyboard backlight to work.

Below are the commands to control it. Check if you have any controls over your fan:

# echo 255 > /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[:print:]]*/pwm1           # Full fan speed (Value: 255)
# echo 0 > /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[:print:]]*/pwm1             # Fan is stopped (Value: 0)
# echo 2 > /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[[:print:]]*/pwm1_enable     # Change fan mode to automatic
# echo 1 > /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[:print:]]*/pwm1_enable      # Change fan mode to manual

If you were able to modify fan speed with above commands, then continue with #Generate config file with pmwconfig.


asus_fan is a kernel module, which allows to control both fans on some older Asus laptops. It does not work with the most recent models.

Install the DKMS asus-fan-dkms-gitAUR kernel module, providing asus_fan:

# modprobe asus_fan

Check if you have any control over both fans:

# echo 255 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm1          # Full CPU fan speed (Value: 255)
# echo 0 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm1            # CPU fan is stopped (Value: 0)
# echo 255 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm2          # Full GFX fan speed (Value: 255)
# echo 0 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm2            # GFX fan is stopped (Value: 0)
# echo 2 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm1_enable     # Change CPU fan mode to automatic
# echo 1 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm1_enable     # Change CPU fan mode to manual
# echo 2 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm2_enable     # Change GFX fan mode to automatic
# echo 1 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm2_enable     # Change GFX fan mode to manual
# cat /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/temp1_input          # Display GFX temperature (will always be 0 when GFX is disabled/unused)

If everything works, you might want to load this kernel module on boot:


Continue with #Generate config file with pmwconfig.

Generate config file with pmwconfig

If you get an error There are no working fan sensors, all readings are 0 while generating config file with pwmconfig, open first console and execute:

# watch -n 1 "echo 2 > /sys/devices/platform/<kernel_module>/hwmon/hwmon[[:print:]]*/pwm1_enable"

If you use asus_fan kernel module and have 2nd fan, in second console:

# watch -n 1 "echo 2 > /sys/devices/platform/<kernel_module>/hwmon/hwmon[[:print:]]*/pwm2_enable"

And finally, in the third console:

# pwmconfig

Once you are done and the configuration file is generated, you should stop the first and second consoles. Continue with Fancontrol (lm-sensors). After config file is generated, you might need to manually replace PWM values with full sysfs paths as they are used in these steps, because hwmon number values might change after reboot.

AMDGPU sysfs fan control

AMDGPU kernel driver offers fan control for graphics cards via hwmon in sysfs.

Configuration of manual control

To switch to manual fan control from automatic, run

# echo "1" > /sys/class/drm/card0/device/hwmon/hwmon0/pwm1_enable

Set up fan speed to e.g. 50% (100% are 255 PWM cycles, thus calculate desired fan speed percentage by multiplying its value by 2.55):

# echo "128" > /sys/class/drm/card0/device/hwmon/hwmon0/pwm1

To reset to automatic fan control, run

# echo "2" > /sys/class/drm/card0/device/hwmon/hwmon0/pwm1_enable
Warning: Resetting fan speed to auto may not work due to a driver bug and instead a restart of the driver may be required as a workaround.


The amdgpu-fanAUR package is an automated fan controller for AMDGPU-enabled video cards written in Python. It uses a "speed-matrix" to match the frequency of the fans with the temperature of the GPU, for example:

speed_matrix:  # -[temp(*C), speed(0-100%)]
- [0, 0]
- [40, 30]
- [60, 50]
- [80, 100]

Once the package can be installed, it can be run as a service, so you can either run it for the current session:

# systemctl start amdgpu-fan.service

or executed at boot

# systemctl enable amdgpu-fan.service

fancurve script

Not just fan controls are offered via hwmon in sysfs, but also GPU temperature reading:

cat /sys/class/drm/card0/device/hwmon/hwmon0/temp1_input

This outputs GPU temperature in °C + three zeroes, e.g. 33000 for 33°C.

The bash script amdgpu-fancontrol by grmat offers a fully automatic fan control by using the described sysfs hwmon functionality. It also allows to comfortably adjust the fancurve's temperature/PWM cycles assignments and a hysteresis by offering abstracted configuration fields at the top of the script.

Tip: In order to function correctly, the script needs at least three defined temperature/PWM cycles assignments.

For safety reasons, the script sets fan control again to auto when shutting down. This may cause spinning up of fans, which can be worked around at cost of security by setting set_fanmode 1 in the section function reset_on_fail.

Setting up fancurve script

To start the script, it is recommend to do so via systemd init system. This way the script's verbose output can be read via journalctl/systemctl status. For this purpose, a .service configuration file is already included in the GitHub repository.

It may also be required to restart the script via a root-resume.service after hibernation in order to make it automatically function properly again:

Description=Local system resume actions

ExecStart=/usr/bin/systemctl restart amdgpu-fancontrol.service



Increase the fan divisor for sensors

If sensors does not output the CPU fan RPM, it may be necessary to change the fan divisor.

The first line of the sensors output is the chipset used by the motherboard for readings of temperatures and voltages.

Create a file in /etc/sensors.d/:

chip "coretemp-isa-*"
set fanX_div 4

Replacing coretemp-isa- with name of the chipset and X with the number of the CPU fan to change.

Save the file, and run as root:

# sensors -s

which will reload the configuration files.

Run sensors again, and check if there is an RPM readout. If not, increase the divisor to 8, 16, or 32. YMMV!