# Annoying ACPI problem - cpu fan stuck at 100%

## epsilon72

I've had an annoying, but non-critical problem with my gentoo desktop for a long time.  The CPU fan spins at a low speed when I first boot up, and when I do something to make the cpu temp rise, the fan spins up to 100%.

The problem is, the fan never reduces speed, even when the cpu has cooled off - so I'm stuck with a loud CPU fan until I reboot.

Windows is able to manage the fan just fine.

dmesg also prints this repeatedly:

```

ACPI: Transitioning device [FAN] to DO

ACPI: Unable to turn cooling device [ffff81007f828100] 'on'

ACPI: Transitioning device [FAN] to DO

```

...and so on.  Those three lines repeat over and over.

Fan, processor, and thermal are all compiled as modules for the kernel and are in my /etc/modules.autoload.d/kernel-2.6 file.

/proc/acpi/fan/FAN/state always lists the status as 'off'.

/proc/acpi/thermal_zone/THRM/cooling_mode says:

```

0 - Active; 1 - Passive

```

/proc/acpi/thermal_zone/THRM/polling_frequency says 'disabled', unless I change it to a number value, which doesn't affect anything.

/proc/acpi/thermal_zone/THRM/state says 'ok'.

/proc/acpi/thermal_zone/THRM/trip_points says

```

critical (S5):           70 C

active[0]:               47 C: devices= FAN 

```

This is all on an Abit KN8 socket 939 nforce4 motherboard with a 3800 x2.

Anyone have any ideas, or have a similar problem?

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## TheAl

Try to upgrade your motherboard firmware and your Linux Kernel.

Seems to be an ACPI bug.

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## epsilon72

 *TheAl wrote:*   

> Try to upgrade your motherboard firmware and your Linux Kernel.
> 
> Seems to be an ACPI bug.

 

My motherboard uses Phoenix bios...but I already have the most up-to-date bios listed on A-bit's product page.  Am I limited to just what is there?

Also, I am using 2.6.24-r8.  The problem has been around for a long time though.

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## pilla

Maybe this can help you:

http://gentoo-wiki.com/HOWTO_Fix_Common_ACPI_Problems

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## epsilon72

 *pilla wrote:*   

> Maybe this can help you:
> 
> http://gentoo-wiki.com/HOWTO_Fix_Common_ACPI_Problems

 

That may be the problem.  I found "MSFT" in an acpi line in dmesg.  I'll try fixing it when I get home from work.  Thanks.

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## epsilon72

 *epsilon72 wrote:*   

>  *pilla wrote:*   Maybe this can help you:
> 
> http://gentoo-wiki.com/HOWTO_Fix_Common_ACPI_Problems 
> 
> That may be the problem.  I found "MSFT" in an acpi line in dmesg.  I'll try fixing it when I get home from work.  Thanks.

 

That wasn't the problem.  I still get the exact same errors.

Maybe it's time to finally ditch this mediocre motherboard?

----------

