[ltp] t42 archlinux fan noise

[Arian Kuschki]

Hi all

I have been using Ubuntu for a couple of years on an x31 and a t42 
without any problems. But now I switched to Arch Linux and for some 
reason then fan on my t42 is always running around 3500 rpm even when the laptop is 
idle for hours (cpu load < 5%). Only very seldomly does it go down to 
3000rpm.

I know there are programs like fancontrol to control fan speed, but I 
was wondering how Ubuntu manages to regulate the fan speed natively. After 
all support for fan regulation on ThinkPads is built into the Kernel 
right? This would the preferred route for me because of efficiency and 
lower risk.

Does anybody know how Ubuntu handles the Thinkpad fan out of the box? If 
there is no other way but to run a script to control fan speed, which 
one do you recommend? Under Arch Linux I think fancontrol is the 
preferred option. And also, if I have to adjust fan speed manually, 
where can I find information about critical temperature thersholds for a 
t42.

Thanks in advance.
Arian
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