On Thu, Apr 17, 2003 at 04:50:14PM -0700, David Brownell wrote: 
> How would you speculate that a hotplug event should be delivered
> to the "system message bus"?   I'm not quite sure how the kernel
> would be expected to authenticate itself, or whether it should.
> If there's going to be a daemon collecting kernel events, I tend
> to think it should be able to read them directly ...

Hmm, that long mail I just sent answered the question "what events go
over D-BUS" not "who sends the events to D-BUS" I guess. ;-) 

How the events get to D-BUS is something I'd defer to kernel hackers
on - I can't say I have an informed opinion.  Basically I gather
there's some minimal hook to get the event to a userspace process, and
that process connects to D-BUS and sends the event.

Easiest way to send an event is with Philip Blundell's dbus-send
command line tool from a shell script. Downside of that is that it
creates a new connection to the bus and redoes some
authentication/handshake work for each event.  If that turned out to
be a performance issue, you'd probably want some sort of daemon that
maintained a permanent connection.

I'll attach two patches Tim Waugh did for the CUPS print daemon and
the "eggcups" print queue monitor icon - these are in the rawhide
packages. They show what's involved.

Havoc