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Date:      Wed, 25 Mar 2009 08:41:52 +0000
From:      Chris Whitehouse <cwhiteh@onetel.com>
To:        Ian Smith <smithi@nimnet.asn.au>, freebsd-acpi@FreeBSD.org
Subject:   Re: acpi_tz0: _CRT value is absurd, ignored (256.0C) (was  pr kern/105537)
Message-ID:  <49C9EE50.6070507@onetel.com>
In-Reply-To: <20090325140718.J95588@sola.nimnet.asn.au>
References:  <49C80E65.9090500@onetel.com> <49C93309.6050708@iki.fi> <20090325140718.J95588@sola.nimnet.asn.au>

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[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?

Chris


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