'port forced close' after failed ppp

[Aleksander Morgado]

On Wed, Mar 8, 2017 at 3:08 PM, Colin Helliwell
<colin.helliwell at ln-systems.com> wrote:
> But this brings me back (in a round-the-houses way!) to my original question: when the PPP fails, for example with the ports assigned the right way round, but on 'faulty' SIM1, why is the PPP port getting "forced closed" and then unable to be retried?
> My concern being if PPP fails for an external reason e.g. at the remote end, then it can't retry?

Forgive my bad memory here. I think the HUP that triggers the "forced
close" in the TTY shouldn't be received by ModemManager, it should be
processed by pppd, which is the one that handles that disconnection.
pppd resets all modem control lines on exit, IIRC. I recall a similar
problem when playing with the NetworkManager integration, which is the
one that would call pppd to establish the connection; I think I solved
it just by making sure pppd is completely closed before Disconnect()
is called for the modem in ModemManager (i.e. so that pppd could
recover the original state of the control lines before passing the
control of the TTY to MM through the Disconnect() call). Does that
make any sense at all?

-- 
Aleksander
https://aleksander.es