[ACPI-sppt] Temperature regulation for a Gateway Solo 1450

Hi,

I have some questions about ACPI-based temperature regulation.  I'm using
a stock 2.4.22 linux kernel on a Gateway Solo 1450 laptop.  It seems as
though the linux ACPI implementation is "happy" with the laptop:  I get a
nice /proc/acpi tree populated with all sorts of files containing useful
information about fans, the battery, lid position, etc..

Now, the cooling fan for the laptop is put in the on state at power-up and
remains there until power-down.  After some searching, the only
suggestions I've seen for silencing it amount to adding a cron job to poll
/proc/acpi/thermal_zone/THRM/temperature at some interval and then
start/stop the fan by writing "0"/"3" to /proc/acpi/fan/*/state
appropriately.

So here's where I'm coming from...  If the only way to turn the fan on and
off is manually in userspace, then acpid more than crond is the correct
way to do this --- turning the fan on and off is not something that needs
to be done periodically but rather something that needs to be done when
certain system status conditions are met.  I do not, however, see ACPI
events being generated as the temperature changes so it is not possible to
use acpid.

Now there is a trip_point file in the thermal_zone/THRM directory with
several temperatures in it.  It seems to me that something, ANYTHING,
should happen when the temperature crosses a "trip point" and yet I see no
change in the behaviour of my system when this happens (no ACPI event, no
fan turning on or off, etc.).  Maybe there's something wrong with my
setup...


In summary, my questions:

What is the meaning of the contents of the "trip_points" file in the
termal_zone/THRM directory?  And what is the relationship between
trip_points and the cooling_mode file in the same directory?

Should I be seeing an ACPI event reported when the temperature crosses any
of the thresholds set in trip_points?  Sould anything happen?

And, basically, is there a way to have the fan turned on and off
automatically without using crond?


Thanks!

							-Kipp



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