acpi_tz0: _CRT value is absurd, ignored (256.0C) (was pr kern/105537)

[Pasi Parviainen]

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 at onetel.com>
> To: freebsd-acpi at 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.