Re: Generic battery interface

Pavel Machek
2006-07-28T12:25:24Z

Hi!

> > >The applets that were doing it (yes, up to 100 times per second)
> > >corrected their ways pretty quickly, because some machines became
> > >unusable with the applet enabled.
> >
> > Exactly -- and they've been working merrily ever since.
> > And if you don't want to trust applet developers, cache the latest
> > reads and refresh them only if X jiffies have passed.
>
> The timer interrupt still has to happen every time their select() or
> sleep() expires, with the system having to wake up, even when nothing
> happened. Polling from userspace is bad.

I do not understand this. Any polling (in kernel or in userspace) will
wake the CPU, wasting power.

OTOH "high/low/very low" battery applet can reasonably query battery
every 5 minutes, while detailed, graphical thingie displaying the
current power consumption will probably poll every 10 seconds...
Pavel
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