[ltp] Re: tpfand configuration for an X200s

[Christoph Bier]

Elias Oltmanns schrieb am 07.12.2008 12:51:

> Christoph Bier <christoph.bier@web.de> wrote:
>> Henrique de Moraes Holschuh schrieb am 05.12.2008 19:37:
> [...]
>>> If the drivers make Windows waste less power, they are not interfering with
>>> fan control but would STILL cause the fan to behave differently (because
>>> there is less waste heat).
>>
>> Yes. But under Linux the fan is running at temperatures at which
>> (right grammar?) the fan is not running under Vista. I would
>> understand if the fan was running more often and even faster under
>> Linux. But it's constantly running---at comparatively low temperatures.
> 
> Please keep in mind that there is not a trivial correlation between
> temperature readings and fan speed. In particular, hysteresis enters
> into it which can be easily observed on my X40. When I keep working for
> a long time with active wlan but otherwise restricting myself to
> lightweight tasks like reading emails, browsing the web, etc. and the
> fan starts spinning eventually (this only happens in a reasonably warm
> environment), then it won't stop for a very long time. On the other
> hand, when I compile the kernel which challenges the CPU as well as the
> HD, then temperature readings rise quickly and the fan gets into gear
> accordingly. Quite shortly after compilation has completed, the fan
> stops spinning at temperature readings that are well above the
> thresholds that would have caused the fan to stop in the first scenario.

Ok, I get your point. Right now I collect data to confirm my
observation. Thereby, I will run 'md5sum /dev/urandom' to challenge
the CPU. Later on I'll post the data.

>> What about my question on thinkpad_ec? Might it effect fan's
>> behaviour? It fails to load on my X200s. Yesterday I tried to
>> install a vanilla kernel (to be able to possibly file a bug in the
>> Kernel Bug Tracker) but compilation failed for reasons I do not
>> understand yet.
> 
> As Henrique said, thinkpad_ec is not directly related to fan control.
> But why would you want to file a bug against the vanilla kernel when
> thinkpad_ec wouldn't load? This module is not even part of mainline.

http://mailman.linux-thinkpad.org/pipermail/linux-thinkpad/2008-November/045358.html

Best
Christoph
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