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

[Jukka Ruohonen <jruohonen%iki.fi@localhost>]

The following reply was made to PR kern/43508; it has been noted by GNATS.

From: Jukka Ruohonen <jruohonen%iki.fi@localhost>
To: gnats-bugs%NetBSD.org@localhost
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

 On Thu, Jun 24, 2010 at 09:50:00PM +0000, demelier.david%gmail.com@localhost 
wrote:
 > When running on AC line, everything works perfectly if I excess a certain
 > temperature fans will raise up. But running on battery I noticed that the
 > fan is completely shut down!
 > 
 > Then I excess 100C° and no fan turns! It's really dangerous because it
 > overheats really soon and after 5-10 minutes the laptop is shut down.
 
 I need the acpidump(8) output to diagnose this further. You can extract the
 so-called DSDT table by issuing:
 
 # acpidump -o foo.dsdt > foo.asl
 
 As it is unlikely that an OEM would make such a fatal flaw, one hypothesis
 could be that the system tries to use so-called "passive cooling policy"
 (see acpitz(4) for discussion) when operating on batteries. This means that
 instead of using fans, it tries to lower the CPU frequencies to deal with
 the heating.
 
 ACPI is under active development and the above scheme is unfortunately not
 yet supported on NetBSD.