Re: cpufreq: allow user to specify voltage

From: Pavel Machek (pavel@suse.cz)
Date: Tue Feb 25 2003 - 14:33:42 EST


Hi!

> > So I guess adding /sys/bus/system/devices/cpu0/voltage? Should code to
> > do that be in kernel/cpufreq.c or is it possible to do sysfs from
> > powernow-k7 [it does not seem easy]?
> Pavel
> I agree, there shoul dbe a way to add sysfs files from a cpufreq driver
> module. I told dave I was looking into overriding the powernow tables,
> but I can't seem to get enough time away from my day job right now.
>
> for the powernow driver, and the userspace governor, I'd like to export a
> file "current_setting" or something that contains:
>
> <frequency> <voltage> <fsb? maybe for other drivers>
>
> A write to this file of one, two, or three values would result in changing
> the frequency to the closest standard table match we have. Unless, the
> user specifies an "override" flag as a module parameter. If the override
> flag is set, then writing to that file will set the speed and voltage to
> exactly what you specify (within the min/max hardware limits), and
> basically ignore the standard BIOS table.

Actually I think sysfs is trying to get it into one-file-per-value...

...which is going to be problem for writing because it will not be
able to atomically update different values at once...

Oh and forget module parameter :-).
                                                                        Pavel

-- 
Horseback riding is like software...
...vgf orggre jura vgf serr.
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