ACPI temperature

[Ian Smith]

On Tue, 8 Dec 2009, Taku YAMAMOTO wrote:
 > On Fri, 4 Dec 2009 23:37:04 -0500
 > Steven Friedrich <freebsd at insightbb.com> wrote:
 > 
 > > I sent this to questions last Sunday, but only one person responded. He's 
 > > running FreeBSD 8 and I think his system is reporting bogus temps too.
 > > I think there might be a missing scaling factor. I'm a hardware guy, but I 
 > > don't currently have temperature measuring equipment and I would want to do it 
 > > on one of my towers (which are currently in storage), not my laptop anyway.
 > > 
 > > I booted my HP Pavilion zd8215us and I immediately invoked chkCPUTemperature.
 > > The first temp reported was 52C, which is 125.6F. This leads me to believe
 > > that acpi has an anomaly regarding temperature measurement. The ambient temp 
 > > was 71F (21.6C). The machine had been off for over eight hours.

Another data point .. my Thinkpad T23, on either 7.0-R or 8.0-R, comes 
up showing between 55-60C immediately after a long sleep, before powerd 
kicks in to drop it back to 44-49C (99% C2 state) - and that at today's 
ambient temp of 36C, ~97F (trying not to drip on the keyboard, phew! :)

 > I'd suggest to kldload coretemp.ko for another point of view; because 
 > it directly retrieves the core temperature from MSR - no ACPI involved.
 > 
 > We can read the core temperature via sysctl dev.cpu.0.temperature like this:
 > 
 >  % sysctl dev.cpu.0.temperature hw.acpi.thermal.tz0.temperature
 >  dev.cpu.0.temperature: 58.0C
 >  hw.acpi.thermal.tz0.temperature: 46.0C
 > 
 > This is obtained from my ThinkPad X60 running in 19C (66.2F) ambient for 15
 > minutes with the lid closed, powerd running, C2 state enabled.
 > 
 > As others stated already, I too think 52C is not so high to worry, though.

Indeed.  FWIW, I can confirm that kldload'ing coretemp on a PIII-M is of 
course useless - but does no apparent harm.

 > # I think it is very convenient to have a knob (or better, honors LANG) to
 > # let sysctl show "IK" oids in Fahrenheit.

No problem with a knob, but referring to LANG won't work for Australia 
at least (using C since the '60s), often installed assuming EN-US, and 
in the case of both a 5.5-S and 8.0-R machine here, both running KDE 3, 
LANG isn't set at all (tcsh):

% set | grep -i lang
% setenv | grep -i lang
%

cheers, Ian