Re: powerbook doubles as a frying pan

On Mon, Jan 29, 2001 at 12:01:26PM +0100, Benjamin Herrenschmidt wrote:

quoted

is everyone *totally* sure that activating the fan is entirely handled in
hardware? is there no
register for controlling the threshold?

I've seen nothing in Apple's own Darwin OS related to controlling the
powerbook fan neither. However, they do have code that use the CPU's
temperature sensors to control the ICTC (instruction cache throttling).

Troy have some code that allow to read the temp from /proc. However, it
looks like a lot of CPUs are so badly calibrated that the information
returned is almost useless... Maybe that's not the case in CPUs used in
portables, that's the case in some of the G4s used in dual G4s.

The IBM manufactured 750's are much better in calibration than the G4's.
Brad, recent 2.4 kernels should have my 'CONFIG_TAU' config option to turn on
the CPU temp monitoring. This code is interrupt driven, so someone could
easily ad code to tweak the ICTC when the temp exceeds certain thresholds.

--------------------------------------------------------------------------
Troy Benjegerdes                'da hozer'                hozer@drgw.net


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	And have you guys tried asking about this power management stuff on
the MacOSX-dev mailing lists at Omnigroup or on the Darwin mailing
lists at Apple?

http://omnigroup.com/community/developer/mailinglists/

http://www.opensource.apple.com//projects/mail.html

=====
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only in your mind." -- http://www.dreamtheater.net/songb4.htm#IV5


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