FreeBSD 5.2-CURRENT on HP Omnibook 6000 - ACPI problem

Kevin Oberman oberman at
Thu Jan 8 09:12:18 PST 2004

> Date: Wed, 7 Jan 2004 22:12:54 -0500
> From: Alexandre "Sunny" Kovalenko <Alex.Kovalenko at>
> Sender: owner-freebsd-current at
> On Wed, 07 Jan 2004 06:58:08 +0000
> "Rob MacGregor" <rob_macgregor at> wrote:
> > I'll have a look at that - thanks.  Out of curiosity, what's the number 
> > reported there actually mean?  Yesterday my laptop was reporting numbers of 
> > around 3350 there, so I'm guessing it's not a literal value in any scale I'm 
> > familiar with.
> Temperature is reported in 0.1 degrees Kalvin with O C = 273 K, so
> 3350 is 62 C.
> As a side note -- I have seen shutdown on my laptop when temperature was raising 
> too fast and fans were not kicking in (I have fair share of mis-features in my 
> ACPI BIOS). I would tend to believe that when temperature raises too rapidly
> ACPI is allowed to shut hardware down without notifying OS to preserve circuitry
> from frying. But this is just AFAIK and I am way out of my depth here.

This is not even ACPI. Many motherboards for modern P4 and K7 chips do a
very low-level BIOS shutdown on over-temp. See ASUS, ABIT, or most any
other mobo for a fairly useless blurb on this.

>From ABIT:
"ABIT ThermalGuard Technology is a special designed for ABIT MB prevents
CPU burning down by hardware cooling malfunction. With unique ABIT
Hardware Monitoring chip and CPU thermal detector, ThermalGuard
Technology can protect the better safety of all CPUs and customers' ABIT
motherboards. When the temperature of CPU is over the default threshold
degree, system immediately shut down by ABIT ThermalGuard It's
great for preventing the lost of customers' investment. Unlike
other manufactories, which use BIOS or software to delivery same
feature. ABIT ThermalGuard Technology is much more reliable because it
is hardware-controlled and uninterruptible."

So, if the fan fails to turn on, it is perfectly possible that the
system will power off regardless of ACPI. While ABIT makes it sound
exclusive, it looks pretty much the same as ASUS "CPU Overtemp Protection
System (COPS)" and Gigabyte calls it "Anti-Burn"
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at			Phone: +1 510 486-8634

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