CPUFreq addon in HAL

[Artem Kachitchkine]

> So how are CPU frequency adjustments done on solaris if at all? Can you
> elaborate a little bit so that I can get a basic overview?

All adjustments are done in the kernel. The user can configure it differently 
though. But it shouldn't matter, since we not only want to cover existing OSes 
in HAL, but also the future OSes. Just keep it as generic as possible.

>> I would also like the interface to be more self-descriptive, sort of
>> like XML is. Instead of hard coding 1-100, have properties for min and
>> max values (and maybe default value, too).
> 
> Something similiar to a configuration file?

Not a configuration file. Just HAL properties that each implementation would 
export to tell the world about itself, e.g.

udi = '/org/freedesktop/Hal/devices/computer'
   power_management.cpufreq.min_value = 1
   power_management.cpufreq.max_value = 100
   power_management.cpufreq.available_policies = {'automatic', 'manual' } 
(string list)

 > I really think that 100
 > different steps should be sufficient for every purpose I can think of.

You never know. One can always map two intervals, but exposing the natural 
interval sometimes provides advantages.

> And that's bad for a OS-neutral app, of course.

HAL's mission is to be good to OS-neutral apps :)

-Artem.