[avahi] Updating the state after coming out from suspend

[Simon Schampijer]

Hi,

at OLPC we have the following issue: when a machine comes out of suspend 
syncing up the collaboration states (until other nodes are visible) 
takes a long time. We use Avahi and Telepathy Salut [1] for that task.

 From a conversation on the olpc-devel mailing list [2] we came to the 
conclusion that notifying Avahi about coming from resume could be one 
part of the solution to the issue. For example the Upower "Resuming" 
signal could be used for that [3].

Avahi could then for example implement the wake-up behavior as specified 
in [4]. The spec does suggest in the section "5.5 Questions Requesting 
Unicast Responses" that one should use unicast responses instead of 
multicast responses in the resume case in order to handle the case 
efficiently.

Tomeu had a quick chat with Lennart already on IRC about it, let's see 
if we can 'resume' the issue solving in this thread.

Thanks in advance for sharing your thoughts,
    Simon

[1] http://telepathy.freedesktop.org/wiki/CategorySalut
[2] http://lists.laptop.org/pipermail/devel/2010-September/029955.html
[3] http://upower.freedesktop.org/docs/UPower.html#UPower::Resuming
[4] http://files.multicastdns.org/draft-cheshire-dnsext-multicastdns.txt