signalling suspend/resume events (deviceKit-power)

Anders Lund anders at
Tue Dec 8 15:07:41 GMT 2009

Richard Hughes skrev:
> 2009/12/8 Dario Freddi <drf54321 at>:
> > But I think a better idea would be having the signal being streamed from
> > upower (since if the aim is providing an unique and future-proof system),
> > triggered from an hook in pm-utils. I think such a solution would be the
> > best of both worlds.
> You have to be careful with signals, as they are not blocking, I mean:
> user clicks suspend
> upower sends Suspending()
> _______________________
> pc is sleeping
> _______________________
> pc awakes
> upower sends Awakening()
> _______________________
> Applications get time to process the Suspending signal call.
> Applications get time to process the Awakening signal call.
> So you get a nice race.
> Richard.

When looking at pm-utils docs and some of the scripts, I thought that the 
easiest thing would be using a signal, because it would be available to 
anyone. But it seems that blocking call is nessecary for applications wanting 
to act prior to a suspend then.

Maybe a signal for resume events would be a good idea in any case, since it 
would cover most (desktop application) usecases (at least cases I see)?

Or would a method call to a desktop specific daemon (powerdevil or solid) 
allow calls in other apps to be executed?

Kind regards,

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