Re: Thinkpad T40 Fan

Do you, or anyone else for that matter, know of any third party utils
for linux that work with the thinkpad t40.  I ran across fantulence, but
lm_sensors was a dependency, and I couldn't install it because it was
incompatable, and damaging, to thinkpad hardware.

On Fri, 6 Feb 2004 11:16:09 +0800
"Ow Mun Heng" [off-list ref] wrote:

quoted

-----Original Message-----
From: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Hmm, how can Windows keep the fan off but Linux can't?

As there is no ACPI fan device, there must be a different method to
control the fan on this box.

1. It may be some i2c device that Windows knows about but Linux does
not?
   Maybe IBM ships some platform specific software with windows?
   Would be interesting to know if a from-scratch install of the
   generic non-IBM windows was still able to keep the fan off.

2. It may be some BIOS code using SMM that Linux somehow breaks?

3. It may be done entirely in hardware without the knowledge 
of the OS?

I'm hopeful that it is #3, and that Windows is simply doing better
passive cooling than Linux -- and perhaps we can perhaps improve our
passive cooling...

Can you run some experiments?  Maybe you can monitor the 
temperature in
windows to see if it really is cooler.  Perhaps you can 
experiment with
the power management policy settings such that it is in 
high-power mode
instead of maximum battery mode and observe the temperature rises,
and at what temperature the fan starts running?

Hi,

	Mine's a D600 which DSDT also does not have fan control.
	(currently 
using i8kfanutil to control it) Under windows it works fine. The fan 
can/will come on/off whenever it gets hot (I didn't do the experiments
casuse I use Linux 95% of the time) The fan _can_ be controlled using
a 3rd party util called FanGui if IIRC. (sort of like i8kfan) but it
works fine generally on it's own without it. 

I was under the impression that it was the BIOS that does this.

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