Date: Thu, 12 Jan 2006 14:29:09 +0100 From: Markus Brueffer <markus@brueffer.de> To: Tobias Roth <roth@iam.unibe.ch> Cc: jt@barfoos.de, mobile@freebsd.org Subject: Re: IBM Thinkpad Fan Control (acpi_ibm) Message-ID: <43C659A5.7080904@brueffer.de> In-Reply-To: <20060110175214.GA2519@droopy.unibe.ch> References: <20060110175214.GA2519@droopy.unibe.ch>
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Tobias Roth schrieb:
> With acpi_ibm.ko, I can monitor fan speed, thermal sensors and do
> many other nice things. However, my Thinkpad (a T43p) has an awfully
> noisy fan, that, once the notebook reaches its standard working
> temperature (around 45 deg C), turns on and never stops again.
>
> The generally accepted solution his to manually lower the fan speed
> and live with the higher temperatures, which will still be in an
> acceptable range even with slow running fans. The discussion and a
> utility for Windows can be found here [1], and a linux tool is
> described here [2].
>
> Now my question. Since acpi_ibm.ko can already read temperature
> sensors and fan speed, would it be feasable to teach it to control
> fan speed as well? Is anyone working on it already? Or can someone
> outline the steps that have to be taken so I can take a look and
> see if I can do it myself?
I didn't see any practical value in setting fancontrol and fanspeed last
year (that was the time when the T43 wasn't yet around), therefore I
didn't implement write support to prevent users from footshooting.
Now that there is a real practical use of it, I have implemented the
missing bits.
>From the new part of the manpage:
dev.acpi_ibm.0.fan
Indicates whether the fan is in automatic (1) or manual (0) mode.
dev.acpi_ibm.0.fan_level
Indicates at what speed the fan should run when being in manual
mode. Values are ranging from 0 (off) to 7 (max). The resulting
speed differs from model to model. On a T41p this is as follows:
0 off
1, 2 ~3000 RPM
3, 4, 5 ~3600 RPM
6, 7 ~4300 RPM
Please try the patch at
http://people.freebsd.org/~markus/ibm/acpi_ibm.c.diff
It should apply cleanly on -CURRENT and 6.0 and works nicely on my T41p.
DISCLAIMER: Use this at your own risk. Messing around with fan speeds
can seriously damage your notebook.
Best regards,
Markus
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