Re: new systemwatch_unix

On Tue, Jul 03, 2007 at 03:15:48PM +0200, emdej wrote:
> 
> > Now that I see the code, I noticed that someone wrote this patch
> > before. We didn't commit it at the time, because 'SIGUSR' doesn't
> > sound like 'The signal emitted on sleep on all Unices', but rather 'A
> > custom signal, which happens to be the one emitted on sleep on a few
> > platforms'. Is this the signal used on all unices to signal sleep? And
> > why is it called SIGUSR? Is there really no *real* signal?
> >
> SIGUSR1 and SIGUSR2 are signals that can be used by any application and 
> have application-defined-meaning. I've added them to make 
> disconnect-on-suspend available for users how can't use other signal for 
> any reason. This signal is never emitted by system! In fact linux don't 
> send any of the signals (AFAIK), they are used by unix or BSD, but can 
> be sent by userspace script called hibernate, which suspends the 
> machine. I've no idea if suspend2 developers would like to change the 
> factory version of hibernate script, I can't get answer from them. I've 
> simply heard from users that it's needed feature (I've the same 
> feeling), so it makes disconnect-on-hibernate possible for them.
> I'm not sure if this version is the one you should apply to official Psi 
> but I know some users would use this patch.
> 

This patch is a nice stopgap for now, but I'd rather not have custom
signals for this in psi in the long term. I hope for 0.12 there will be
enough DBus infrastructure in place in psi to implement it one way or
the other with DBus.

I'm not sure if there is already a standard for this using DBus, or
if there is only the defacto interfaces power manager uses, but in the
worst case we can add simple DBus commands for this to Psi.

 - Martin