Prestigio Nobile 157 ACPI - overheating

[Kevin Oberman]

> From: Milan Bartos <merlyn500 at gmail.com>
> Date: Mon, 1 Oct 2007 19:03:15 +0200
> Sender: owner-freebsd-acpi at freebsd.org
> 
> Hi. I have laptop Prestigio Nobile 157 and i am running 6.2-STABLE. Kernel is 
> GENERIC. I have my proc dev.cpu.0.freq=1000 to have temperature about 54 
> Celsius. If a have dev.cpu.0.freq=1700, temperature is over 70 Celsius. Is 
> this bug, unsuported acpi device or attribute my laptop?
> My dmesg following:
> 
[-snip-]
> 
> Please, help me, all you will need (some sysctls or anything else) i
> will send you.

OK. People need to learn a bit about the normal temperatures of modern
CPUs (as well as how they are measured).

You have a 1.6GHz Pentium-M. The CPU temperature is measured on the
silicon by a single junction that is tied to two pins on the
package. The temperature you see is going to be higher than whet you saw
on many older systems with a temperature sensor mounted under the CPU in
the socket. These showed a lower temperature due to the combination of
convection and thermal conduction.

Your CPU is most likely a 735. If so, it is speced for operation to 100C
and thermal shutdown forced at 125C. 70C is not really all that hot. My
system tends to idle at about 55C and, during a big build
(e.g. buildworld or openoffice.org) will climb to about 85C. This is higher
than I used to see, but I suspect I need to remove the keyboard and
clean the heat sink. Dust accumulation can really impact thermal
transfer and the laptop is now 2.5 years old.

Really, what you are seeing is pretty normal. You can see what the
vendor thought was too hot by looking at 'sysctl hw.sysctl.thermal'.
Look at values for PSV and CRT. PSV is when the system should start
aggressive thermal control by forcing the performance down. CRT is when
the systems should alarm and, depending on configuration, start a
shutdown.

On my 2G Pentium-M I see:
hw.acpi.thermal.tz0._PSV: 94.5C
hw.acpi.thermal.tz0._CRT: 99.0C

So even 80C is not excessive. Just very uncomfortable if you really have
the laptop on your lap.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
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