[lug] cpu temp/throttling

[Hugh Brown]

I started noticing these messages in my logs (on my terminals):

May  3 17:07:43 localhost kernel: CPU0: Temperature above threshold
May  3 17:07:43 localhost kernel: CPU0: Running in modulated clock mode

I'm interested to learn how the kernel has determined that info.
I had assumed that this was related to ACPI, but I can't find anything
useful.

/proc/acpi/thermal_zone/ is an empty directory

cat /proc/acpi/processor/CPU1/limit
active limit:            P0:T0
user limit:              P0:T0
thermal limit:           P0:T0


which I understand to mean that reaching a thermal limit won't actually
change the state of the processor.

So, where does the kernel get the info about the temp of the cpu?
Currently, I do not have lm_sensors installed, but there are some i2c
modules installed.

I'm running the stock debian/etch 2.6.18 kernel on a P4.

Everything I've found from STFW was "install lm_sensors (which is a bear,
but worth it)"

Hugh