Re: [linux-pm] OpPoint summary

From: Scott E. Preece
Date: Mon Sep 18 2006 - 09:36:45 EST



| From: Pavel Machek<pavel@xxxxxx>
|
| Hi!
|
| > >Care to resend your patches in the proper format, through email so that
| > >we can see them, and possibly get some testing in -mm if they look sane?
| >
| > Greg,
| > here's the patch that implements operating points for different
| > frequencies
| > for the speedstep-centrino line of processors. Operating points are created
| > in much the same manner that cpufreq tables are. This works for both
| > simple implementations like the centrino and more complex SoC systems
| > like the arm-pxa72x which has several clocks to control, and different clock
| > divisors and multipliers.
|
| > +static struct oppoint lowest = {
| > + .name = "lowest",
| > + .type = PM_FREQ_CHANGE,
| > + .frequency = 0,
| > + .voltage = 0,
| > + .latency = 15,
| > + .prepare_transition = cpufreq_prepare_transition,
| > + .transition = centrino_transition,
| > + .finish_transition = cpufreq_finish_transition,
| > +};
|
| We had nice, descriptive interface... with numbers. Now you want to
| introduce english state names... looks like a step back to me.
---

Well, a single number is fine if you're describing a scalar abstraction,
but an operating point is a vector. You can't assume that "399" is three
times "133" in performance or energy cost, so its "numberness" is simply
misleading.

scott

--
scott preece
motorola mobile devices, il67, 1800 s. oak st., champaign, il 61820
e-mail: preece@xxxxxxxxxxxx fax: +1-217-384-8550
phone: +1-217-384-8589 cell: +1-217-433-6114 pager: 2174336114@xxxxxxxxx


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