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Date:      Wed, 25 Mar 2009 09:06:35 -0700
From:      Nate Lawson <nate@root.org>
To:        "Alexandre \"Sunny\" Kovalenko" <gaijin.k@gmail.com>
Cc:        freebsd-acpi@FreeBSD.org, Ian Smith <smithi@nimnet.asn.au>, Chris Whitehouse <cwhiteh@onetel.com>
Subject:   Re: acpi_tz0: _CRT value is absurd, ignored (256.0C) (was  pr  kern/105537)
Message-ID:  <49CA568B.6030305@root.org>
In-Reply-To: <1237992462.1297.22.camel@RabbitsDen>
References:  <49C80E65.9090500@onetel.com> <49C93309.6050708@iki.fi>	<20090325140718.J95588@sola.nimnet.asn.au>	<49C9EE50.6070507@onetel.com> <1237992462.1297.22.camel@RabbitsDen>

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Alexandre "Sunny" Kovalenko wrote:
> On Wed, 2009-03-25 at 08:41 +0000, Chris Whitehouse wrote:
>> [Please would you cc me in any reply as I'm not subscribed, thanks.]
>>
>> Ian Smith wrote:
>>> On Tue, 24 Mar 2009, Pasi Parviainen wrote:
>>>  > Chris Whitehouse wrote:
>>>  > > Hi, I sent this a while ago but don't think there was a reply. I'm about to
>>>  > > embark on a custom ASL to load in loader.conf as per
>>>  > > http://www.freebsd.org/doc/en/books/handbook/acpi-debug.html but just
>>>  > > wondering if their might be a 'proper' fix on the way. I do have the latest
>>>  > > bios installed.
>>>  > 
>>>  > Loading custom ASL with modified _CRT value for temperature zone in
>>>  > question will solve the problem, see below for more information.
>>>  > 
>>>  > > Would it help if I installed 8-CURRENT?
>>>  > 
>>>  > Probably not, see below.
>>>  > 
>>>  > > -------- Original Message --------
>>>  > > Subject: pr kern/105537
>>>  > > Date: Mon, 12 Jan 2009 15:00:49 +0000
>>>  > > From: Chris Whitehouse <cwhiteh@onetel.com>
>>>  > > To: freebsd-acpi@FreeBSD.org
>>>  > > 
>>>  > > hi,
>>>  > > 
>>>  > > Please would you cc me in any reply as I'm not subscribed, thanks.
>>>  > > 
>>>  > > I have the same problem noted in
>>>  > > 
>>>  > > http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/105537
>>>  > > 
>>>  > > of frequent messages saying
>>>  > > 
>>>  > > acpi_tz0: _CRT value is absurd, ignored (256.0C)
>>>  > > 
>>>  > > on my HP nc6320 laptop, model RH383ET.
>>>  > > 
>>>  > 
>>>  > I have HP 6510b and HP 2510p laptops and had same problem with those.
>>>  > Actual problem is that the ACPI thermal code in kernel does sanity-check
>>>  > for temperature values, and accepts only values between 0 - 200 Celsius.
>>>  > To solve the problem you either create custom DSDT which returns 200.0C
>>>  > value instead of 256.0C for thermal zone in question or increase the limit of
>>>  > the sanity-check code of ACPI thermal code (src/sys/dev/acpica/acpi_thermal.c
>>>  > function: acpi_tz_sanity).
>>>  > 
>>>  > Proper way to solve this in my opinion is to increase the range of
>>>  > sanity-check function from 0 - 200 Celsius to 0 - 256 Celsius, or at
>>>  > least provide sysctl variable to disable thermal sanity-checks.
>>>
>>> Even 200C is absurd, really.  That's above the melting point of many 
>>> types of solder (http://www.rfcafe.com/references/electrical/solder.htm) 
>>> while 256C exceeds the melting point of _most_ types of solder.  I seem 
>>> to recall that this limit used to be 150C, still hotter than anything 
>>> you actually want to have anywhere on a computer board.
>>>
>>> No sense checking sanity to then accept insane values; fix the broken 
>>> ASL.  256 sounds suspiciously like a byte-swapped value, perhaps?
>>>
>>> cheers, Ian
>>>
>> Getting the ASL in the actual BIOS firmware fixed would be great, but I 
>> tried once to get Asus to correct a byte swapped value without success. 
>> I don't suppose HP will be any more cooperative but I can try. I will 
>> have a look at an acpidump tonight. A custom ASL would at least prove 
>> what is wrong.
>>
>> Does anyone know what this value is supposed to be measuring?
> _CRT method in ASL is supposed to return temperature (in the tenth of
> Kelvin) at which you would like to have your computer shut down rather
> rapidly. On my ThinkPad X60 it is 97C. 
> 

> To be fair, if all you want is to override _CRT, you should be able to
> put something to the tune of
> 
> hw.acpi.thermal.user_override=1
> hw.acpi.thermal.tz0._CRT=90C
> 
> in your /etc/sysctl.conf and not deal with the ASL at all.

Yes, this is the best way instead of messing with ASL.

-- 
Nate



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