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

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

On Wednesday 09 April 2008, Zhang, Rui wrote:
> > > In current kernel when RTC alarm time is set and not fired,
> > > it is impossible to set RTC alarm again. But it is more
> > > reasonable that the RTC alarm time can be overrided.
> > 
> > I'll disagree.  The problem is that if some task is waiting
> > for the alarm at the specified time, you've just trashed the
> > alarm it was relying on.
>  
> 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.

The current behavior doesn't prevent such borkage; it
can't, really, because of the alarm model.  What it does
instead is force whatever shell script is doing that to be
explicit about *intending* such borkage ... requiring it
to disable existing alarms, instead of allowing accidents.

- Dave
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