cpufreq(4) panic on RELENG_7 (was: Re: Call for bfe(4) testers.)

Ulrich Spoerlein uspoerlein at gmail.com
Sat Aug 9 11:29:49 UTC 2008

Hi John,

I now figured out the "who", the "why" still eludes me.

So, after your MFC of ichss.c on June 27th the device now attaches at my
laptop. It didn't before, so it could cause no trouble.

With ichss loaded, the kernel will panic 1-3 minutes after powerd has
been started (if I kill powerd early enough, it seems pretty stable).

I'm now running a kernel from 2008-08-08 with

Applying your patch to kern_cpu.c does not help though. I'll be happy to
try further patches to make ichss behave well, although I'll never use
it for this laptop, as EST is the only technique useful on this old

> > Will also disable p4tcc. This was not attaching during the RELENG_6
> > times but leads to ridiculous rates of 75 MHz.
> If p4tcc attaching is new, that might point to the culprit.  A good quick test 
> would be to disable individual cpufreq drivers to find out which one causes 
> the panic.

p4tcc attaching was new relative to RELENG_6, not relative to my
working 7.x kernel of 2008-06-13.

Ulrich Spoerlein
It is better to remain silent and be thought a fool,
than to speak, and remove all doubt.

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