The future of Power Management - together with Activities

Andras Mantia amantia at
Sun Oct 2 11:04:15 BST 2011

On Saturday, October 01, 2011 23:13:06 Dario Freddi wrote:
> > Is it? Certainly disabling desktop effects and 3D acceleration has
> > an
> > impact.
> Sorry to disappoint you, but this action will be removed in 4.8.
> Martin has explicitely stated that for how compositing in KDE works
> now turning off compositing is actually going to harm your battery
> instead of saving it - feel free to get in touch with him to expand
> on this topic, which is not exactly relevant to this discussion.

That was one example. Another example brought up is e.g switching of 
strigi or nepomuk indexing when switching to a power saving profile. 
These two are something that usually kick in when you are in idle mode, 
exactly when the battery power could be saved. Of course, with good 
default profiles this can be solved.

> > And there are other things like when to suspend automatically (if
> > do it at all), when to dim the display, etc.
> I agree, but are you sure you need to configure these things
> separately depending on where you are? If you are, say, working on a
> train, you're very likely to never be idle, and to suspend the PC on
> your own by closing the lid when not active to save the most power.
> How can a different profile help you here?

What I said that I might manually need to switch to a different profile 
independent of what the battery power *currently* is and without 
switching my workflow/applications. Because I know in advance (before the 
software can find this out from the battery level dropping down) how much 
time I need the computer running. 

> > So I think there are more settings then display brightness (that
> > you usually can control anyway with an Fn shortcut on laptops).
> Again, as I said before, I am pretty sure there are no settings except
> brightness which require you to change to a different profile - in
> fact, there is a reason why brightness handling works this way at the
> moment.

You keep saying this, but sorry, I can just as well keep saying the 
opposite. :) Do you have some research showing this is true? If this is 
true, why would we have power magement configurations at all? Just as 
with turning off wifi with a hardware button, brightness can be changed 
from the hardware (well, software,  but usually independent of the 
running OS).
Certainly CPU wakeups, disk, perfipherials, etc. have an impact on 
battery life. 

What should be configurable is another thing. In perfect life, indeed we 
should just have good defaults. 

> Provided some good reasons, I will. But I think atm you are wasting
> your time creating new profiles, while you could achieve the same by
> tweaking your brightness. This kind of placebo-effect of switching to
> a profile with a different name is something I was fearing from day
> 1.

Isn't good enough reason what was said in this thread? I'm not the only 
one feeling it weird that configuring power management is tied to 
activities. And even if we have good defaults (that we should) for 
peformance/agressive power saving, then it is still weird that you 
cannot change the active setting without switching to a new activity. 
That is what people try to explain here.
And it is just as weird, if you CAN tweak the power management settings, 
but you cannot do that without creating a new activity. It was already 
asked here: is there a technical reason why you couldn't do that? 


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