Modem creation/startup order

Aleksander Morgado aleksander at
Tue Feb 14 11:33:38 UTC 2017

On Tue, Feb 14, 2017 at 11:39 AM, Colin Helliwell
<colin.helliwell at> wrote:
>> > Thanks. The question arises from needing to have monitoring & URCs etc on one port of my mux driver, and ppp on the other - I need to make sure that ppp doesn't get run on the 'monitoring' port i.e. the one that gets in first with having the URCs enabled.
>> > This all makes me think I need this 'primary'/'secondary' port stuff - after all that's more or less what the mux is doing too.
>> > Perhaps I can modify Cinterion's grab_port() to flag the ports as primary/secondary? (They're /dev/ttyMux0, /dev/ttyMux1). Does this sound feasible, or is there more to the dual-portness than that....?
>> Just setup new Cinterion-specific udev rules to flag ports as primary
>> or secondary, as done in other plugins; e.g.
>> ID_MM_SIMTECH_PORT_TYPE_MODEM (primary+ppp) or
> I've made that change in grab_port() and in the udev rules and it seems to be doing the flagging. But is the idea that the two [virtual] ports should show up as a single modem? (mmcli -L)
> If so, then I reckon I need something more somewhere - the debug is showing, for both ports, messages including:
> [src/mm-plugin-manager.c:979] device_context_continue(): [plugin manager] task 0: no more ports to probe
> [src/mm-device.c:525] mm_device_create_modem(): Creating modem with plugin 'Cinterion' and '1' ports
> [plugins/cinterion/mm-plugin-cinterion.c:175] grab_port(): (tty/ttyMux0)' Port flagged as primary  {or PPP on the other}
> [src/mm-base-modem.c:280] mm_base_modem_grab_port(): (ttyMux0) type 'at' claimed by /sys/devices/virtual/tty/ttyMux0
> [src/mm-base-modem.c:864] log_port(): (/sys/devices/virtual/tty/ttyMux0) tty/ttyMux0 at (primary)
> [src/mm-base-modem.c:864] log_port(): (/sys/devices/virtual/tty/ttyMux0) tty/ttyMux0 data (primary)

Yes, the idea is that both ports end up grabbed in the same modem. How
are these ports exposed by the kernel? Not via the usb subsystem it
seems? MM needs a way to find a common "physical device sysfs path"
for both ttys.


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