Re: [PATCH net-next v9 1/2] net: Add a WWAN subsystem

[Aleksander Morgado]

Hey,

>
> * Note: Userspace tools like ModemManager are able to link control
> ports and netdev by looking at the sysfs hierarchy, it's fine for
> simple connection management, but probably not enough for 'multi PDN'
> support for which devices may have multiple netdev and ports
> targetting different 'PDN contexts'...
>

ModemManager is happy with those devices exposing multiple netdevs
(even connecting different net ports to different contexts/bearers and
such), as long as we can bind all those ports together to the same
"modem device". The sysfs hierarchy has been enough for now for that
purpose; or better said, without the sysfs hierarchy it would not have
worked properly. E.g. there are some drivers out there allowing to
instantiate virtual net ports from a master net port; without proper
links in sysfs to link those virtual net ports to the master net port,
the setup would be extremely unstable.

-- 
Aleksander
https://aleksander.es