The future of Power Management - together with Activities

Dario Freddi drf54321 at
Sat Oct 1 22:19:36 BST 2011

On Saturday 01 October 2011 21:30:02 Lukas wrote:
> On 1 October 2011 21:36, <plasma-devel-request at> wrote:
> > > Something like having Power mode switch:
> > > 
> > > [Performance] [Normal] [Battery stretch]
> > > 
> > > where Normal is current static profile; Performance - temporary
> > > disables any limitations; Battery stretch - disables everything, that
> > > can be disabled [Wifi, audio, CPU turbo mode etc]
> > 
> > This is actually why we thought about pairing profiles and activities.
> > Although your concern is valid, you are likely to require this kind of
> > things
> > when doing a specific activity, hence you won't need the applet :) On the
> > other hand, inhibition might be useful everywhere.
> Not exactly. Those switches was intended to be only temporary changes.

So are activities.

> Lets say you are on the trip on the train using "Plasma development"
> activity. Usually, all your development activities are set to average power
> usage profile, but since the journey is long, and you are not listening to
> music, nor using wifi [Battery stretch] could give you e.g +25% of battery
> time.

That's a dream-world assumption (like the 25% which pardon me, but it's 
slightly random). First of all, you can turn off your wi-fi through an 
hardware switch, which is usually what people do (although, if in the future 
powerdevil will be able to do that, great). Second, then how you define a 
"battery stretch?" You would need a dozen of those states to cover all corner 

> Other situation, you are giving a presentation on how to make a best of QT,
> that requires compiling using the same using "Plasma development"
> activity. Performance mode could at the same time disable any screensaver,
> as well give green light to use all CPU power, ignoring the battery usage.

And that's why the applet is now able to inhibit. CPU is not affected by 

> Both are quite unusual but possible situations, but creating new activity
> and moving all files/settings does not pay off.

But in both cases, you don't need a separate profile/mode. We thought about 
much worse corner cases while discussing, and we still need to figure out one 
which explicitly needs a new profile.

> Also [Performance] and [Battery stretch] power modes could do more by e.g.
> preventing any daemons (nepomuk, akonadi, owncloud) from staring background
> works - a common complaint, that KDE semantic services starts at a very bad
> time and there is no way to prevent them.

That's indeed to be fixed inside those daemons - if we were to start thinking 
like this, KDE would be the land of workarounds.

> Cheers,
> Lukas


Dario Freddi
KDE Developer
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