Re: RFC: powerd Patch & proposed future changes

Hi,

Rene Schickbauer wrote:
> Yesterday i submitted a patch for powerd to set maximum allowed CPU speed
> for adaptive modes (to keep the system cool and using less power).

Thank you for your work.


> Would it also make sense to have powerd run an (optional) user configureable
> script on ac state change? I'm thinking about things like dimming TFT
> backlight, on EEE PC turning of the webcam and so on.

No.  As pointed out, devd(8) does this already.


> Another option that could make sense in powerd is checking the battery state
> and running a user configureable script when ac-state is set to battery and
> battery falls below a configured threshold. The script could do a number of
> things like warning the user, scheduling a shutdown and so on in order to
> give the user a fair chance to save his/her work and do a clean shutdown (or
> just plugin the ac adapter).

As for the notification script at low capacity, in theory devd(8) should 
be able to do this as well.  A notebook ought to generate a battery 
event when capacity hits its factory set "warning" and "low" marks.  Of 
course I say this without having tested it on mine. :)


> powerd currently only adjusts CPU speed, but having a *second* programm
> monitor the same kernel variables to work on another part of the same
> problem does not seem to make sense.
> 
> BTW, i'm also thinking of having the option to have powerd log the battery
> status (ac mode + load + charge level) every 5 Minutes or so to syslog. That
> way, a second script (log parser) may be able to determine information about
> the battery - like how long does it take to charge, rough capacity
> estimation and possible degradation of battery.

Seems unnecessary.  That information is already available with 
acpiconf(8) and via sysctl(8) (see hw.acpi.acline, hw.acpi.battery), so 
someone is able to write their own logger if they wish.

IMHO, I think powerd should be kept doing only work that's most useful. 
  As I've experienced with power saving, the moment you start doing more 
and more work to save power, you also end up consuming more power.  Keep 
it simple.


Regards,
Aragon