This is the port to git master of the following commit:
commit d1be19d231a395339b1f452d1a30b73ea77ad528
Author: Dan Williams <dcbw@redhat.com>
Date: Tue Aug 28 21:58:43 2012 -0500
sierra: fix CSQ handling on APP1 port
The APP1 port doesn't always prefix its replies with <CR><LF> which
runs afoul of the built-in echo removal. Since Sierra modems are on
the whole well-behaved WRT echo removal, just disable it on the
secondary ports. Only changes behavior for PPP-based devices since
they are the only ones that use the APP1 ports.
Different ports of the same modem may get handled by different drivers. We
therefore need to provide a list of drivers (new `Modem.Drivers' property with
signature 'as') instead of just one (removed `Modem.Driver' property with
signature 's').
$ sudo mmcli -m 0 | grep drivers
| drivers: 'qcserial, qmi_wwan'
Aleksander Morgado