[PATCH] info to atm layer about broken connection

[Stanislaw Gruszka]

Hi Duncan
> > Finish internet connection when modem is disconnect form usb port, 
> > additionally force root to disable connection before unloading 
> > subdriver module. Tested with pppoatm.
> 
> I've committed the vcc_release_async stuff (check it out from
> cvs.infradead.org).  My experiments so far show that it works
> as expected, i.e. if you have an open socket then when the
> device is disconnected, it is the same as the connection being
> closed, eg: if you were reading from the socket, then the read
> completes; any writes get EPIPE, etc.  So it should cause pppd
> to shut down.  My ISP doesn't support pppoa or pppoe, so I can
> only do artificial tests - I haven't done any yet, but I will.
> Can you please try it out?
As I wrote before vcc_release_async() don't work for ppp. 
I tried to investigate how does ppp driver work (I don't finished yet, and
i really don't know as much text below is true ).

Pppoatm plugin for pppd ceate pvc socket,
and only configure it (by setsockopt, ioclt, connect). 
It is not used for sending/receiving any data, 
syscall on socket are preformed only for proper
merge atm layer with ppp net driver. 
Vcc_release_async() only stop working pvc socket, 
but in ppp it's not used, so release_async() do nothing. 
To disable ppp connection low level kernel driver
need to call ppp_unregister_channel() as do push
function in pppoatm.ko when it receive NULL skb.

I will try to track problem down, it's quite difficult
cause it cross many kernel layers (net core, atm, ppp).

__
Regards
Staszek Gruszka