# Fan Control (Solved why it happens but not how to fix it)

## ilovebeer

hello, my fan is on constantly so i'm trying to get some control going. when i run fancontrol i get this;

fancontrol

Loading configuration from /etc/fancontrol ...

Common settings:

  INTERVAL=10

Settings for 0-0d90/pwm1:

  Depends on 0-0d90/temp2_input

  Controls 

  MINTEMP=40

  MAXTEMP=55

  MINSTART=15

  MINSTOP=0

  MINPWM=0

  MAXPWM=255

Enabling PWM on fans...

/usr/sbin/fancontrol: line 232: 0-0d90/pwm1: No such file or directory

Error enabling PWM on /sys/bus/i2c/devices/0-0d90/pwm1

Aborting, restoring fans...

/usr/sbin/fancontrol: line 189: 0-0d90/pwm1: No such file or directory

Verify fans have returned to full speed

In fact i have nothing at all under /sys/bus/i2c/devices/

I would be most grateful if someone knows the cause and cure or could point me in the right direction.

thankyou.Last edited by ilovebeer on Tue Nov 25, 2008 4:27 am; edited 2 times in total

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## Sadako

My guess is that you don't have the required hwmon or i2c modules loaded.

If you played with the lm_sensors detection script when setting up fan control in the first place, then check out /etc/sensors.conf for the list.

Otherwise, try playing with sensors-detect again, and then just insure the required modules are loaded in future by whatever means you like.

(I prefer to just build the required drivers into the kernel directly, as they're always loaded anyways).

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## ilovebeer

Hello Hopeless, Thanks for your reply. I checked it all out and I did have all the proper modules loaded. I even tried building them in to the kernel but same result... nothing under /sys/bus/i2c/devices/. not to worry though i'll keep fiddling until I find the cause. I do however have /dev/i2c-0 through to /dev/i2c-5. Fan just a tad annoying. Both CPU's are currently running at 19c and the fan never stops. Don't think a fan is needed at those temps. Thankyou

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## Sadako

Do you have anything under /sys/class/hwmon/ ?

All the same devices should be available under that too.

Also, this is a case fan and not a cpu fan you want to control, right?

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## ilovebeer

Thanks Hopeless, I have;

localhost linux # /sys/class/hwmon/hwmon

hwmon0/ hwmon1/ hwmon2/  there.

With pwmconfig I am getting this message;

 [code]pwmconfig 

This program will search your sensors for pulse width modulation (pwm)

controls, and test 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.

We will attempt to briefly stop each fan using the pwm controls.

The program will attempt to restore each fan to full speed

after testing. However, it is ** very important ** that you

physically verify that the fans have been to full speed

after the program has completed.

/usr/sbin/pwmconfig: There are no pwm-capable sensor modules installed

which I think is probably relevant but how I don't know   :Rolling Eyes: 

Thankyou

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## Sadako

Screw fancontrol, just see if there's and pwm# files (ie pwm1, pwm2) within /sys/class/hwmon/*/device/, if so then you'll be able to control your fan by echoing a value from 0 to 255 to it.

On mine, pwm3 does nothing/isn't connected, pwm2 is the cpu fan and can only be controlled via the bios/cool'n'quiet (but at least that works fine), and pwm1 is the case fan.

I have '/bin/echo 144 > /sys/class/hwmon/hwmon0/device/pwm1` within /etc/conf.d/local.start, which has the fan spinning at ~1,700 rather than up to 2,100 rpm's, making it more or less silent.

Anyways, if you get the right /sys/class/hwmon file you can configure fancontrol manually, or just do what I do.

The lm_sensors utilities are generally a pain in the arse.

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## ilovebeer

Hello, yes i agree hopeless... it's all rather a pain in the arse. i have found out though that this is a widespread problem with the thinkpad SL series for which there is currently no solution http://forums.lenovo.com/lnv/board/message?board.id=SL_ThinkPads&thread.id=125&view=by_date_ascending&page=1. Lenovo are apparently working on a fix with the next bios update and are well aware of the problem. The cpu core setting displayed in thinkpad power control reports that the threhold for turning off the fan is a miserly 10c and basically the fan is almost always on level 2 rarely going to (sitting in a fridge might help) level one and never ever turning off. Lenovo appear to have been very very conservative with their settings! I guess i'll just wait for the update because no userspace program is very effective. thanks for your input... much appreciated. Thankyou

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