screensaver and power manager dbus interfaces

[Rodrigo Moya]

On Fri, 2006-06-02 at 14:09 +0200, Holger Macht wrote:
> > 
> > Richard
> > 
> > -------------- next part --------------
> > The GNOME Power Manager DBUS API
> > ------------------------------
> > 
> > This API is currently unstable and is likely to change in the future.
> > 
> > GNOME Power Manager exposes a DBUS API for programs to obtain
> > information about the DPMS state and to change it if required.
> > 
> > The following constants are used to uniquely refer to the
> > PowerManager object when making DBUS method calls:
> > 
> > DBUS Service:		"org.gnome.PowerManager"
> > DBUS Object Path:	"/org/gnome/PowerManager"
> > DBUS Interface:		"org.gnome.PowerManager"
> > 
> > Methods
> > =======
> > 
> > 	Name:		Suspend
> > 	Args:		(none)
> > 	Returns:	BOOLEAN
> > 	Description:	This call will attempt to suspend the system.
> > 
> > 	Name:		Hibernate
> > 	Args:		(none)
> > 	Returns:	BOOLEAN
> > 	Description:	This call will attempt to hibernate the system.
> > 
> > 	Name:		Shutdown
> > 	Args:		(none)
> > 	Returns:	BOOLEAN
> > 	Description:	This call will attempt to shutdown the system.
> 
> Why do we need this in a power managmenet context. I think all desktop
> will provide such a "Shutdown method" via dbus regardless of power
> management.
> 
I think it makes sense here, in power management interface, since
shutdown = power off. I would even add Reboot here, now that you mention
this.

> > 
> > 	Name:		CanSuspend
> > 	Args:		(none)
> > 	Returns:	BOOLEAN
> > 	Description:	This call Finds if the current user in the session
> > 			is able to suspend, and has permission to do so.
> > 
> > 	Name:		CanHibernate
> > 	Args:		(none)
> > 	Returns:	BOOLEAN
> > 	Description:	This call Finds if the current user in the session
> > 			is able to hibernate, and has permission to do so.
> 
> How is this ment to be? Does it just a mirror the corresponding HAL
> methods power_management.can_hibernate/suspend? If so, I think we don't
> need it. Desktops will have a close connection to Hal anyway to query Hal
> itself for this information IMHO.
> 
> If the Can{Suspend,Hibernate} methods are not meant to state this, what I
> think we need is something like...
> 
> 	AllowedSuspend and
> 	AllowedHibernate
> 
yeah, this sounds much better, and should return whether the user making
the call is allowed to suspend/hibernate. Maybe I would leave
CanSuspend/Hibernate, to return whether the current system can
suspend/hibernate.

> > 
> > 	Name:		setDpmsMode
> > 	Args:		STRING
> > 			value:	on		100%
> > 				standby		<80%
> > 				suspend		<30W
> > 				off		<8W
> > 	Returns:	(nothing)
> > 	Description:	DPMS is a standard from the VESA consortium for
> > 			managing the power supply of monitors.
> > 			This call requests a change in the state of DPMS for
> > 			the current screen.
> > 
> > 	Name:		getDpmsMode
> > 	Args:		(none)
> > 	Returns:	STRING
> > 	Descriptions:	Returns the DPMS mode state.
> > 			See setDpmsMode().
> 
> Do we really need them? We have the X extensions/functions for that.
> 
for the same reason I think we should add the Reboot and keep Shutdown
methods, I think it's better if apps use only a standard interface for
all power management-related tasks than having to use dbus for some
operations, X libs for another, etc. Of course, as you say, this is just
a convencience wrapper, but that would make it easier for the developer,
I think.
-- 
Rodrigo Moya <rodrigo at gnome-db.org>