[review] New 'fibocom' plugin

[Aleksander Morgado]

> On Chrome OS, we simply use ID_MM_PORT_IGNORE to ignore all AT ports
> on the L850-GL module (e.g.
> https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/master/net-misc/modemmanager-next/files/77-mm-fibocom-port-types.rules).
>
> The modem is functional with just MBIM and supported via the generic
> plugin, which is the approach we took on Chrome OS. IMHO, there is
> little added benefit with a new modem plugin. More importantly, AT
> probing takes quite some time, and I observed it often took 7 seconds.
> We've been trying hard for some time to move everything to purely MBIM
> or QMI :)
>

I'm going to extend this plugin in the following weeks with more
features that will require the use of the AT port, e.g. GPS location
and such. I agree that probing is a bit slow right now, but that is
just because the DIAG port goes first through a series of AT probing
steps which are not needed. For devices with fixed layouts like this
one, adding udev tags to specify port types isn't bad IMO, and we
should probably do that for the DIAG port (i.e. flag it as "not AT"
for example).

-- 
Aleksander
https://aleksander.es