Use a specific device ?

[Bjørn Mork]

Dan Williams <dcbw at redhat.com> writes:
> On Thu, 2015-05-28 at 22:26 +0200, Jean-Christian de Rivaz wrote:
>> I you follow the previous paragraph, you will understand that it's 
>> clearly the job of ModemManager. This just plain logic as this is the 
>> only entity in the chain that receive the udev event about the modem.
>
> I don't necessarily think it is ModemManager's job.  Since what you want
> in the end is to tie a specific NM connection to a specific modem (based
> on type, slot #, whatever), it's the job of NetworkManager to figure
> that out for you.  ModemManager can certainly help if we can figure out
> a clean generic way to do that.

FWIW, I agree here.

Once you have more than one modem/SIM/operator/whatever, then you cannot
automatically do-the-right-thing-for-everyone.  You can select
reasonable defaults of course, but the final modem selection policy
should be user controlled.

There is no way MM or NM can know that one of my modems dont' have any
antennas connected, or that my operator only allows 3G so that LTE is
irrelevant, or that my internal modem tends to overheat, or ... I'm sure
you get the point.

Even simple things like internal vs external might be hidden from MM.
All modems are connected by USB to the same controllers.  We do have the
port/connect_type attribute nowadays, but that information comes from
the PC firmware (ACPI), and we can be pretty sure there is at least one
system getting it wrong.

Every system and user is different. Policies have to be user defined.
Which implies configuration. So NM is the lowest level where you can
make this decision.



Bjørn