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Re: kern/43508: fan are shut down in any case if running on battery

2010/6/25 Jukka Ruohonen <>:
> The following reply was made to PR kern/43508; it has been noted by GNATS.
> From: Jukka Ruohonen <>
> To:
> Cc:
> Subject: Re: kern/43508: fan are shut down in any case if running on battery
> Date: Fri, 25 Jun 2010 07:50:50 +0300
> ÂOn Thu, Jun 24, 2010 at 09:50:00PM +0000, 
> wrote:
> Â> When running on AC line, everything works perfectly if I excess a certain
> Â> temperature fans will raise up. But running on battery I noticed that the
> Â> fan is completely shut down!
> Â>
> Â> Then I excess 100CÂ and no fan turns! It's really dangerous because it
> Â> overheats really soon and after 5-10 minutes the laptop is shut down.
> ÂI need the acpidump(8) output to diagnose this further. You can extract the
> Âso-called DSDT table by issuing:
> Â# acpidump -o foo.dsdt > foo.asl
> ÂAs it is unlikely that an OEM would make such a fatal flaw, one hypothesis
> Âcould be that the system tries to use so-called "passive cooling policy"
> Â(see acpitz(4) for discussion) when operating on batteries. This means that
> Âinstead of using fans, it tries to lower the CPU frequencies to deal with
> Âthe heating.
> ÂACPI is under active development and the above scheme is unfortunately not
> Âyet supported on NetBSD.

Sorry for the painful attachment. Here you can see the ACPI table :

Demelier David

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