Re: New modules in 2.14

[William Jon McCann <mccann jhu edu>]

Hello Ryan,

You have some interesting comments about power management.  I too have 
been thinking about this recently and I have a few questions and comments.

Ryan Lortie wrote:
[snip]
> Certainly, at the current time, it appears to be the best offering.
> However, after discussing this at length at Ubuntu Below Zero, I
> believe, that we'd be better served by a system with the two following
> key properties:
>
> 1. Based on system daemon.
>   This would make the system more secure as a normal user process
>   wouldn't be given the ability to 'suspend now' as g-p-m (and 
>   any system which makes policy decisions at user privilege) currently
>   requires we provide it with.  This (and other privileges that g-p-m
>   need to be provided with) have serious security implications.
>   Having a system daemon would also mean that the policy system runs
>   when the user is not logged in without resorting to hacks like gdm
>   invoking a private copy of g-p-m.

Can you provide some reasons why you think g-p-m has "serious security 
implications"?

How is a system daemon more secure than a user session daemon?

g-p-m doesn't require any additional privileges.  HAL is doing most of 
the work.

I think the whole on-console issue is a complicated one and one that 
certainly isn't limited to power management.  It seems to me that most 
of your arguments apply equally to gnome-volume-manager or any of the 
other session daemons.

> 2. More platform-neutral approach.
>   The technologies on which g-p-m is based have seen wide acceptance
>   from other desktops.  We should try and create a power management
>   system that has the same acceptance.  g-p-m is very Gnome-centric.
>   With a faceless system daemon doing all the real hard work we could
>   have multiple configuration front-ends (Gnome, Qt, etc).

Can you please provide some reasons why g-p-m is "very Gnome-centric"? 
It uses the system tray standard and provides a DBUS interface that any 
application can use.  This DBUS interface could be standardized with 
freedesktop.org once we figure out what works for us.  Yes, it has GNOME 
in its name and uses Gconf and GTK+.

> Of course, this wonderful system does not exist.  Again,
> gnome-power-manager is the best offering we have at this time.

Great.

> This does not mean, however, that we should put include it in Gnome
> proper.  Once things are in, they have a tendency to stay around
> forever.  Applications form hard dependencies on them.  If we are going
> to standardise on a solution it should be the best possible solution --
> not just the best thing that we have right now.  If we aren't sure that
> the thing we have now is the best possible solution then it's
> appropriate to wait.

Adding an application to the Desktop release doesn't make too many 
guarantees about its API availability.

> Another issue is that right now some distributions are using power
> management systems that are vastly different from how g-p-m works.  If
> we include g-p-m we are encouraging people to depend on it and making
> life difficult for those distributions that do not want to ship it.

I think it is the interface that counts.  As long as the DBUS interface 
is sane then you should be able to plug whatever you want in to provide 
that service.

> Essentially, I think that (a) we should not rush into this and (b) we
> should, at the current time, leave this up to distributions to decide.
> We do them no harm by not including it since they can include it anyway.

Historically, distributions have always been able to make their own 
choices regardless of what was in the Desktop and I think this can still 
be true.

The question comes down to: is there sufficient reason not to use the 
best solution we have in favor of one that hasn't been spec'd, reviewed, 
or developed in the community or at all?

Thanks,
Jon