[maemo-developers] Internet Tablet Power Management presentation from linux-pm summit 2007

From: Igor Stoppa igor.stoppa at nokia.com
Date: Wed Jul 11 15:39:43 EEST 2007
On Wed, 2007-07-11 at 13:28 +0100, ext Andrew Flegg wrote:
> On 7/11/07, Igor Stoppa <igor.stoppa at nokia.com> wrote:
> >
> [snip lots of interesting stuff]
> >
> > It's a similar case to sleep while idle vs user-controlled suspend: just
> > because old devices were doing suspend that doesn't make it desirable.
> This being reraised made me think about why, the other day, I *did*
> want user suspend. Sometimes I just want a quick way to:
>   * Shut off all network connections.
>   * Stop any noise (except configured alarms)
>   * Have the screen locked
>   * Not have to save my position
>   * Be able to resume quickly
> This isn't "suspend" in a power sense, but in a use-case sense the
> purpose is clear.

Why not just put it in offline mode and lock the screen and keys?

That's what i do and it simply works.

The only drawback is that with sane applications you would get "only" 12
days with a full battery.

I do admit that in some extreme case it might not be enough, but on
OMAP2 it doesn't justify the hassle.

I'd rather spend time and resources in fixing kernel and applications to
make sleep while idle as close as possible to suspend to ram.

Plain suspend to ram (or disk), imho, sucks, because it produces a
useless brick till it is forcibly resumed. I think it would be much
better to simply let wakeup events happen, but make sure that only the
_useful_ ones happen.

The user should be able to configure wakeup sources, certainly, even up
to the point of saying: wake up only for power button, but the system
should manage itself automatically.

Cheers, Igor

Igor Stoppa <igor.stoppa at nokia.com>
(Nokia Multimedia - CP - OSSO / Helsinki, Finland)

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