org.freedesktop.PowerManagement

[David Zeuthen]

On Thu, 2007-03-22 at 13:37 +0000, Richard Hughes wrote:
> > > boolean GetLowPowerMode (void)
> >
> > This method, is it the same as the one exported by HAL? I mean, the one
> > that comes from pm-utils?
> 
> No, it's a user preference version of it. Imagine this method
> returning false when we are on AC, or > 50% on battery, but returning
> true when <50% of battery. That point where the system is "low" is
> probably best defined in the session, so KDE can make it configurable,
> and gnome can hardcode something semi-sane. ;-)

It might be better to call it something else than GetLowPowerMode() as
what you really want to do is to give applications a hint whether they
should operate in a mode that makes the system as a whole consume less
power. Perhaps call it GetPreferPowerSavings() instead and do give
examples in the docs for where this is useful e.g. a) desktop search; b)
media playback; c) screensaver; d) sound server; and so on and so on.

FWIW, perhaps off-topic here, I think we _do_ want g-p-m to provide an
option here. Personally, I don't want g-p-m to try to be "smart" and
guess what _I_ as an user want. Btw, I know 2.16 had this

 http://people.freedesktop.org/~david/g-p-m-prefer-power-savings.png

but for some reason it's missing in 2.18 which is a regression but the
maintainer never responded to me

 http://bugzilla.gnome.org/show_bug.cgi?id=414436

Hint hint, nudge, nudge :-)

(Justification: suppose Totem/gstreamer used this, which I think we
want, and that it chose the video decoder accordingly; e.g. if
GetLowPowerMode()->TRUE the video quality is superb but makes my CPU run
at 1.8GHz. If ->FALSE then the video quality would be worse but in
return the CPU would run at 1.2GHz and I would get 30 minutes more
runtime; you know so I could actually finish watching the damn movie.
Morale: I, as an user, really don't want g-p-m to make this decision;
for me, and I guess, lots of other people it's a real user preference.
To me at least.)

    David