Re: Changing temperature trip points

Pavel Machek
2002-11-03T20:21:30Z

Hi!

> > > I did in fact try that, and while it lets me change the values, they
> > > don't actually seem to affect the kernel's idea of when the fan should
> > > come on, if at all. I set the active trip point to 45 C and the passive
> > > to 50 C, then ran a compile to see if the fan triggered. While the
> > > temperature got above 50 C, the fan never came on. In fact, I don't
> > > know if the fan would come on even if the originally-specified trip
> > > points were reached. Either way, this isn't exactly the most comforting
> > > situation to observe.
> >
> > That's because your fan is driven by hardware, not ACPI. I see it
> > here, too. Passive cooling should work, through.
>
> Actually, I think the problem is something else: The BIOS is supposed to
> generate ACPI events whenever these trip points are reached. So if you
> change these values (by patching the DSDT, by "hardwiring" it into the
> kernel) you need to use the polling method. Then ACPI will compare the
> current temperature to the specified temperatures with a specified
> frequency. Any chance you can try whether my assuption is correct?

YOU are right that I need to turn the polling on.

But I'm sure fan is done by bios on my machine.

Here is what my cool-it-down script looks like:

root@amd:~# cat watchtemp
#!/bin/bash
echo "83:83:60:70:0" > /proc/acpi/thermal_zone/THRM/trip_points
echo "5" > /proc/acpi/thermal_zone/THRM/polling_frequency
watch '( cat /proc/acpi/processor/CPU0/limit ; cat
/proc/acpi/thermal_zone/THRM/{temperature,state,trip_points} )'
root@amd:~#

Pavel

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