Re: Kernel 2.4.23 passive cooling

[Karol Kozimor <sziwan-DETuoxkZsSqrDJvtcaxF/A@public.gmane.org>]

Thus wrote Nils Faerber:
> Hi!
> Passive cooling still seems a little strange, at least to me on my Asus
> L3800C notebook.
[...]
>  - passive cooling works until it reaches the first hot state. After
> that the fan(s) power up for a very short time and the CPU performance
> is set to maximum (!) again. The performance setting can afterwards not
> be reset to low performance anymore; it will be reset to high
> automatically!

Use the limit interface instead of directly manipulating the
CPU0/performance -- this *may* help.

> Is there any chance that this will be fixed?
> Or is this a BIOS bug?

I'm not sure, but I haven't really had enough time to trace the appropriate 
AML codepath -- I can obviously also experience the problem. Oddly enough,
the first time I booted ACPI 20031002 (just in order to see if improved
index field access will fix the passive cooling problem), the processor
went up to about 83 C without the fan kicking in (I can't remember if
throttling was on at that time, but I guess it should have been). I then
switched to active (the fans started spinning like mad), and back to
passive, which apparently didn't stop the fans.

What I suspect is that there are some semi-obscure things going on in the
AML and it would take me at least two or three cups of coffee to trace it.
I'll see what I can do.

Note: most of the thermal management is done by the AML and not by the OS,
as th OS doesn't know about most tresholds.

Best regards,

-- 
Karol 'sziwan' Kozimor
sziwan-DETuoxkZsSqrDJvtcaxF/A@public.gmane.org


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