slightly OT: lightdm problem with ubuntu 15.10

[John G Heim]

I'm installing ubuntu 15.10 via FAI. Actually, all I did was take a 
working ubuntu 15.04 config and change the sources.list file so it 
installs ubuntu 15.10 on selected machines. The beauty of FAI is how 
easy it is to do something like that. The main problem I'm having is 
that there is no network or sound icon on the lightdm login screen. And 
the problem with that is that without sound, the accessible logins don't 
work. I'm blind myself butsince this is a university, we're legally 
required to have an accessible login anyway.

Anybody have a clue as to why sound wouldn't work in lightdm? I am sorry 
to ask a question that is a little bit OT but I am just really stumped.

My sighted colleague tells me that there is a menu bar at the top of the 
screen just like in a working ubuntu machine but the sound and the 
network icons are missing. Logins work though. You get sound after you 
log in and the screen reader works fine.  I examined the lightdm logs 
and see nothing meaningful.