Re: [RFC] [PATCH 1/3] Allow to override the RTC alarm time

[David Brownell <david-b@pacbell.net>]

On Wednesday 09 April 2008, Zhao Yakui wrote:
> > > Hmm, what if the wakealarm is set by mistake?
> > > is there any chance that user can fix it?
> > 
> > Certainly; there are several ways to turn an alarm off.
> > With sysfs, just write a time in the past, as I recall...
> > 
> > If you're concerned about accidents, think of it this way:
> > the proposed patch would make it *REALLY EASY* to have
> > accidents with sysfs that bork the alarm state, which can
> > have been set by some task that's relying on it.
> 
> But how to solve the following case?
> 
> It is assumed that the RTC alarm is set by some task and not fired (It
> will be fired after 20 minutes). The system enters the sleeping state
> and is required to be resumed after some time(For example: ten minutes).
> 
> How to set the RTC alarm?

You mean, how to decide which alarm setting should "win"?
If sysfs accidents aren't going to trump everything else.

That's a fair question.  I don't think there's a good answer
to that with today's infrastructure.  Arguably, there should
be the notion of a number of clients, each of which get told
when the alarm they request fires.  But today, there's only
a single alarm, and a single client.

- Dave