How to control fan speed?

The script I run every few seconds to keep my Dell server cool and quiet. Update the get_temp for your hardware.

#!/bin/env python3

import os
import json

MIN_FAN = 5
MAX_FAN = 100

MIN_TEMP = 50 # fans at min at this temp
MAX_TEMP = 80 # fans at max at this temp

TEMP_POW = 3 # decrease for cooler server, increase for quiter

def get_temp():
    sensors = json.loads(os.popen('/usr/bin/sensors -j').read())
    temp0 = sensors["coretemp-isa-0000"]["Package id 0"]["temp1_input"]
    temp1 = sensors["coretemp-isa-0001"]["Package id 1"]["temp1_input"]
    return max(temp0, temp1)

def determine_fan_level(temp):
    x = min(1, max(0, (temp - MIN_TEMP) / (MAX_TEMP - MIN_TEMP)))
    return int(min(MAX_FAN, max(MIN_FAN, pow(x, TEMP_POW)*(MAX_FAN-MIN_FAN) + MIN_FAN)))

def set_fan(fan_level):
    # manual fan control
    os.system("ipmitool raw 0x30 0x30 0x01 0x00")
    # set fan level
    cmd = "ipmitool raw 0x30 0x30 0x02 0xff " + hex(fan_level)
    os.system(cmd)

temp = get_temp()
fan = determine_fan_level(temp)
print("temp", temp, "fan", fan)
set_fan(fan)

Here is an updated answer, based on the answer recommending thinkfan but working with Ubuntu 19.04, and also on other computers than just ThinkPads.

1. Setup

The instructions below apply to any ThinkPad that has the /proc/acpi/ibm/fan and /proc/acpi/ibm/thermal "legacy" devices. This avoids having to install the lm-sensors package.

However, you can still opt to install lm-sensors. It will give you more temperature sensors and more fine-grained control over your fans, namely in 256 PWM steps rather than the fixed steps "0-7 and 127" with the legacy devices. Also, since thinkfan now can work with lm-sensors sensors, it is no longer specific for IBM / Lenovo ThinkPad computers. Please refer to man thinkfan for using these "extended" sensor devices. Also, there is up-to-date information in the German Thinkwiki.

1. Install the required package:

   sudo apt install thinkfan
   

2. Add the following line to /etc/modprobe.d/thinkfan.conf:

   options thinkpad_acpi fan_control=1
   

3. Configure the thinkfan service to start automatically at system start:

   1. Add a line START=yes to /etc/default/thinkfan

   2. Execute the following command (source):

      sudo systemctl enable thinkfan.service
      

4. Adapt /etc/thinkfan.conf with the right pointers to devices and the fan levels you want. The comments there provide documentation. On any Thinkpad with the legacy fan and thermal devices, the following should provide a good starting point (also should be safe for the hard disk, see comments in the file for more information). Note that this uses new keywords – the ones in the other answer are now deprecated.

   tp_fan /proc/acpi/ibm/fan
   tp_thermal /proc/acpi/ibm/thermal
   
   (0, 0, 47)
   (1, 43, 52)
   (2, 48, 55)
   (3, 51, 58)
   (4, 54, 63)
   (5, 59, 70)
   (6, 66, 79)
   (7, 74, 92)
   (127, 85, 32767) 
   

2. Test

To test your setup (after a reboot), you can do as follows:

• In one terminal window, run thinkfan in non-daemonized mode so you can see its messages:

  sudo service thinkfan stop && sudo thinkfan -n
  

• In another terminal window, keep an eye on the current temperature values, supplying your temperature probe device if different:

  while true; do sleep 1; cat /proc/acpi/ibm/thermal; done
  

• In yet another terminal window, make some heat in the CPU (and interrupt it with Ctrl + C in case something in the thermal management does not function as expected):

  sudo apt install stress-ng
  stress-ng --cpu-1
  

Try looking in the UEFI setup (or BIOS setup) of your PC. There might be a setting for fan control where you can put your fan into Silent Mode, Performance Mode, Full Speed, Customize, etc.

How to access the UEFI settings: Reboot your PC and the key for entering them will likely show up in one of the corners (e.g. Press F2 to enter UEFI setup)

For several Dell computers you can install i8kutils package:

sudo apt install i8kutils

If you have a non-tested Dell (like my Dell XPS 14z), you might have to force loading of kernel module:

sudo modprobe i8k force=1

If you own a ThinkPad, there's a piece of software called thinkfan that does exactly this. As the name obviously suggests, it is specifically made for ThinkPads (thinkpad_acpi).

The thinkfan software is available in the standard ubuntu software repositories, but it does require a few steps to configure.

Here's an easy step-by-step guide:

http://www.lxle.net/forums/discussion/821/how-to-set-up-thinkfan-on-a-lenovo-thinkpad-t430/p1

(which is basically a translated version of this German guide: http://thinkwiki.de/Thinkfan)

---

Relevant Information from Post:

Step 1. Install the thinkfan software and the sensors:

sudo apt-get install thinkfan lm-sensors

Step 2. Make sure that the daemon controls the fan by editting the thinkpad.conf file:

sudo nano /etc/modprobe.d/thinkfan.conf

by adding the following line:

options thinkpad_acpi fan_control=1

Step 3. Make the daemon load automatically at start-up by editting the file:

sudo nano /etc/default/thinkfan

making sure that the START key is set to yes, i.e. there should be a line that says:

START=yes

Step 4. Detect your laptop's sensors:

sudo sensors-detect

and just choose the default answers whenever you're prompted by hitting Enter.

Step 5. Load the new modules. From ubuntu 13.10 this done by:

sudo service kmod start

while for previous versions like 13.04 you instead will need to do:

sudo service module-init-tools start

Step 6. Figure out which sensors are in use:

sensors

(the ones that indicate 0 degrees are not in use, I don't know why those are "detected" too). Remember which ones are in use.

Step 7. Find out the full paths of these sensors:

find /sys/devices -type f -name "temp*_input"

The output should be a list of paths like /sys/devices/...

Step 8. Copy-paste the paths to the sensors into the configuration file /etc/thinkpad.conf. To do this, first open up the file:

sudo nano /etc/thinkfan.conf

There should already be a line like

#sensor /proc/acpi/ibm/thermal (0, 10, 15, 2, 10, 5, 0, 3, 0, 3) 

(the #-symbol means that that line is commented out). Add a line starting with sensor (without the #-symbol) and copy-paste you first sensor. Repeat this if you have more than one sensor. For example, on my machine, the output in step 7 yields

/sys/devices/virtual/hwmon/hwmon0/temp1_input
/sys/devices/platform/thinkpad_hwmon/temp3_input
/sys/devices/platform/thinkpad_hwmon/temp4_input
/sys/devices/platform/thinkpad_hwmon/temp5_input
/sys/devices/platform/thinkpad_hwmon/temp6_input
/sys/devices/platform/thinkpad_hwmon/temp7_input
/sys/devices/platform/thinkpad_hwmon/temp1_input
/sys/devices/platform/thinkpad_hwmon/temp8_input
/sys/devices/platform/thinkpad_hwmon/temp2_input
/sys/devices/platform/coretemp.0/temp4_input
/sys/devices/platform/coretemp.0/temp2_input 

The ones that are in use in my machine are the ones in the first and the last two lines, so I added the three lines:

sensor /sys/devices/virtual/hwmon/hwmon0/temp1_input
sensor /sys/devices/platform/coretemp.0/temp4_input
sensor /sys/devices/platform/coretemp.0/temp2_input 

Step 9. Finally we can set the fan speed levels in the configuration file. Open the /etc/thinkpad.conf file if it wasn't open already.

sudo nano /etc/thinkfan.conf

The fan levels I use on my ThinkPad x201 are:

(0, 0, 51)
(1, 50, 52)
(2, 51, 55)
(3, 54, 58)
(4, 56, 63)
(5, 60, 70)
(6, 66, 79)
(7, 74, 92)
(127, 85, 32767) 

The last line ensures full fan speed (127 = "disengaged" i.e. unregulated). You can fiddle with these levels to fit your needs/wishes, but PLEASE BE CAREFUL!

Step 10. Reboot. Everything should work now. In order to check whether thinkpad is runnning correctly, use

sudo thinkfan -n

which starts thinkfan in verbose mode. You might want to stop the thinkfan daemon first:

sudo /etc/init.d/thinkfan stop

If you want to start the thinkfan daemon again, type:

sudo /etc/init.d/thinkfan start

Just to be complete, my /etc/thinkfan.conf configuration file is:

# IMPORTANT:
#
# To keep your HD from overheating, you have to specify a correction value for
# the sensor that has the HD's temperature. You need to do this because
# thinkfan uses only the highest temperature it can find in the system, and
# that'll most likely never be your HD, as most HDs are already out of spec
# when they reach 55 °C.
# Correction values are applied from left to right in the same order as the
# temperatures are read from the file.
#
# For example:
# sensor /proc/acpi/ibm/thermal (0, 0, 10)
# will add a fixed value of 10 °C the 3rd value read from that file. Check out
# http://www.thinkwiki.org/wiki/Thermal_Sensors to find out how much you may
# want to add to certain temperatures.

# Syntax:
# (LEVEL, LOW, HIGH)
# LEVEL is the fan level to use (0-7 with thinkpad_acpi)
# LOW is the temperature at which to step down to the previous level
# HIGH is the temperature at which to step up to the next level
# All numbers are integers.
#

# I use this on my T61p:
#sensor /proc/acpi/ibm/thermal (0, 10, 15, 2, 10, 5, 0, 3, 0, 3)

#(0, 0, 55)
#(1, 48, 60)
#(2, 50, 61)
#(3, 52, 63)
#(4, 56, 65)
#(5, 59, 66)
#(7, 63, 32767)


# My settings for my ThinkPad X201: (kris)

sensor /sys/devices/virtual/hwmon/hwmon0/temp1_input
sensor /sys/devices/platform/coretemp.0/temp4_input
sensor /sys/devices/platform/coretemp.0/temp2_input

(0, 0, 51)
(1, 50, 52)
(2, 51, 55)
(3, 54, 58)
(4, 56, 63)
(5, 60, 70)
(6, 66, 79)
(7, 74, 92)
(127, 85, 32767)

Note before starting:

This functionality depends on both your hardware and software. If your hardware doesn't support fan speed controls, or doesn't show them to the OS, it is very likely that you could not use this solution. If it does, but the software (aka kernel) doesn't know how to control it, you are without luck.

---

1. Install the lm-sensors and fancontrol packages.

2. Configure lm-sensors as follows:

   1. In terminal type sudo sensors-detect and answer YES to all YES/no questions.
      (Potentially, this can damage your system or cause system crash. For a lot of systems, it is safe. There is no guarantee that this process will not damage your system permanently, I just think that chance of such critical failure is really really low. Saving all your work for eventual crashes/freezes/restarts before handling system configuration is always good idea. If you feel unsure, read the comments and try to search a web and get some high-level overview before YES-ing everything, maybe being selective with your YES-es will still be enough)

   2. At the end of sensors-detect, a list of modules that need to be loaded will be displayed. Type "yes" to have sensors-detect insert those modules into /etc/modules, or edit /etc/modules yourself.

   3. Run sudo service kmod start This will read the changes you made to /etc/modules in step 3, and insert the new modules into the kernel.

      • Note: If you're running Ubuntu 12.04 or lower, this 3rd step command should be replaced by sudo service module-init-tools restart

3. Configure fancontrol

   1. In terminal type sudo pwmconfig . This script will stop each fan for 5 seconds to find out which fans can be controlled by which PWM handle. After script loops through all fans, you can configure which fan corresponds to which temperature.
   2. You will have to specify what sensors to use. This is a bit tricky. If you have just one fan, make sure to use a temperature sensor for your core to base the fancontrol speed on.
   3. Run through the prompts and save the changes to the default location.
   4. Make adjustments to fine-tune /etc/fancontrol and use sudo service fancontrol restart to apply your changes. (In my case I set interval to 2 seconds.)

4. Set up fancontrol service

   1. Run sudo service fancontrol start. This will also make the fancontrol service run automatically at system startup.

In my case /etc/fancontrol for CPU I used:

Settings for hwmon0/device/pwm2:
(Depends on hwmon0/device/temp2_input) (Controls hwmon0/device/fan2_input)

  INTERVAL=2
  MINTEMP=40  
  MAXTEMP=60  
  MINSTART=150  
  MINSTOP=0  
  MINPWM=0  
  MAXPWM=255 

and on a different system it is:

  INTERVAL=10
  DEVPATH=hwmon1=devices/platform/coretemp.0 hwmon2=devices/platform/nct6775.2608
  DEVNAME=hwmon1=coretemp hwmon2=nct6779
  FCTEMPS=hwmon2/pwm2=hwmon1/temp2_input
  FCFANS=hwmon2/pwm2=hwmon2/fan2_input
  MINTEMP=hwmon2/pwm2=49
  MAXTEMP=hwmon2/pwm2=83
  MINSTART=hwmon2/pwm2=150
  MINSTOP=hwmon2/pwm2=15
  MINPWM=hwmon2/pwm2=14
  MAXPWM=hwmon2/pwm2=255

[here][1] is some useful info on the settings and what they really do

[1]: https://www.systutorials.com/docs/linux/man/8-fancontrol/

Install and configure the lm-sensors and fancontrol packages:

sudo apt-get install lm-sensors fancontrol

Documentation for configuring them is available on their man pages.

This is a function that is supposed to be provided by a ACPI-compliant BIOS, but it seems that most motherboard vendors don't bother to follow the standard.