Re: accessing core temp sensors in the kernel

[Andrew Morton <akpm@linux-foundation.org>]

On Fri, 15 Feb 2008 16:12:40 -0500 "Dan Upton" <upton.dan.linux@gmail.com> wrote:

> I'm trying to do some work on thermally-aware scheduling, specifically
> using the coretemp module to access core temperature sensors on the
> Intel Core2 platform.  I know how to access them from user mode,
> reading files from sysfs, but clearly that's not the way to do it in
> the kernel.  Specifically, I'm not sure how, in the scheduler, to get
> copies of the appropriate device structures to call
> 
> static struct coretemp_data *coretemp_update_device(struct device *dev)
> 
> (in hwmon/coretemp.c).
> 
> Can anybody give me pointers where to get started?

You shouldn't make the core scheduler dependent upon some hwmon module. 
I'd sugggest adding some register_cpu_temperature_monitor() function in the
scheduler then permit suitable monitoring modules to register themselves in
their module_init() functions.  Use a notifier chain from notifier.h.  The
CPU scheduler will walk that chain calling into the registered drivers at a
suitable time.