# CPU fans race when loading it87 module for lm-sensors.  Why?

## gcostanz

I'm trying to use lm-sensors.  I've compiled I2c modules and lm-sensors and all went well.  Sensors detect reports:

```

# I2C adapter drivers

modprobe i2c-i801

modprobe i2c-isa

# I2C chip drivers

modprobe it87

modprobe eeprom

#----cut here----

```

All modules load without errors.  I can use gkrellm to report data on fan speed and temperatures.  However, when I modprobe it87, the CPU fan revs to full speed.  I've read the FAQ at the lm-sensors site, but I don't see anything specific to this problem.  I'm guessing the module is probing some port, and that is causing problems.  I'm at a loss what to check next.

I'm using a shuttle with an 845GE intel chipset.

Anyone have any suggestions?

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## weltraumfahrer

Hi,

> I'm using a shuttle with an 845GE intel chipset.

me too, with the same problem:-(

This is a known problem of the module (found somewhere in the www).

For me, i've replaced the original fan with a papst fan, who runs always at full speed (1500 RPM).

Frank

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## gcostanz

Hey thanks.   This is a big help and time saver.  I don't thinkt that I'll spend any time on this right now.  I'll keep on the look-out for an updated module.

Cheers!

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## BlackB1rd

Just curious if there is already a solution for this one. I am experiencing the same increase of fan speed after modprobing this module (it87).

[edit] Took some time to search the lm_sensors site and found this bug report: http://www2.lm-sensors.nu/~lm78/readticket.cgi?ticket=1204

Editing it87.c might be a solution, though haven't tested it out yet

[/edit]

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## lazarusrat

BlackB1rd,

I did the edit suggested in the link you gave, and it did fix the problem for me (Shuttle SB51G).

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## rob.sharp

For the sake of anyone searching on this problem, the "patch" also fixed the problem on my Shuttle SN 41G2.

Bear in mind that doing this relies on the BIOS to control the temperature, so make sure you have the appropriate settings.

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## torklingberg

I had the same problem with an Asus K8V motherboard, with the CPU fan controlled by the board's Q-fan system. The fan went to full speed wheneither i loaded the w83627hf or w83781d modules. 

I solved it by adding the init=0 option when loading w83627hf, like

```
modprobe w83627hf init=0
```

Btw, for the forums searchers wanting to know how to enable the sensors, this is how I did:

1. Compile everyting under i2c as modules. 

2. emerge lm-sensors, and run sensors-detect. It will tell you what modules you want to load. 

3. Now you can remove the modules you dont need, and even unmerge lm-sensors (probably)

For me, the modules are:

i2c-viapro

i2c-isa

w83627hf

i2c_core and i2c_sensor is in lsmod too, but I cant remember loading them manually.

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## serendipity

I have not had this problem on my Shuttle SB75G2. I have, however, noticed that the fan control through pwm settings does not work as expected, so this type of problem is not surprising. I found that there is no correlation between fan rpm and pwm value over the full fan range : full pwm range.

On my FB75 mainboard. the fan is at 0 rpm at a pwm of 4, at one notch less than full at 30 (over the continuous range 4 - 30), and max rpm is set at a pwm value of 101. Odd, but I write a script to test it, and this behaviour is totally consistent.

I use a hacked version of fancontrol from the lm_sensors userspace tools, and I find that it does an excellent job of keeping the CPU and chipset at the right temperature while keeping my noise level as low as possible.

Oh, and it does a lot better job than the BIOS.

----------

