Re: u-blox R410M modem (QMI) configuration with modern Network-manager

[Dan Williams <dcbw redhat com>]

On Fri, 2018-11-30 at 11:24 -0800, Tim Harvey wrote:
> On Fri, Nov 30, 2018 at 3:12 AM Aleksander Morgado
> <aleksander aleksander es> wrote:
> > Hey,
> >
> > > I'm trying to use a u-blox QMI R410M with network manager on
> > > Ubuntu
> > > bionic witht he following which works fine on Ubuntu xenial:
> > >
> > > # nmcli connection add type gsm ifname cdc-wdm0 con-name mymodem
> > > apn $APN
> > > # nmcli connection up id mymodem
> > >
> > > The modem's QMI interface is indeed /dev/cdc-wdm0, my APN is
> > > correct,
> > > and I can connect just fine using mmcli or qmicli directly.
> > >
> > > On Xenial with network-manager-1.2.6 this works fine but on
> > > Bionic
> > > with network-manager-1.10.6 this results in 'Error: Connection
> > > activation failed: No suitable device found for this
> > > connection.'.
> > >
> > > I'm thinking the connection configuration syntax has likely
> > > changed
> > > I'm I'm simply using the wrong syntax?
> > >
> > > Note that I'm using libqmi-1.20.2 and modemmanager-1.8.2 from
> > > Aleksander's Ubuntu PPA's in both cases.
> >
> > I'm not totally sure what might have changed in NM, but have you
> > tried
> > creating the connection *without ifname*?
> > You can have "gsm" connection settings not bound any interface, NM
> > will try to find a suitable device when connecting.
>
> hmm... I wonder if that's not available until a newer version of NM?
>
> root@bionic-newport:~# nmcli --version
> nmcli tool, version 1.10.6
> root@bionic-newport:~# nmcli connection add type gsm con-name mymodem
> apn $APN
> Error: 'ifname' argument is required.

Yeah, that's a bug in nmcli:

https://bugzilla.gnome.org/show_bug.cgi?id=780323

I think you can delete the ifname after you create the connection
though.

> I've always thought the 'gsm' and 'cdma' types are a bit outdated for
> modern LTE modems but it looks like that is what your supposed to
> continue using according to the NM docs.

These days "gsm" means any GSM, UMTS, and LTE provider, even if the LTE
provider still runs a CDMA network. The modem hides the details of CDMA
for you. We may be able to deprecate it in a few years when most of the
CDMA/EVDO networks are shut down.

The NM distinction for cdma & gsm existed before LTE was a thing, and
NM values backwards compatibility, so it's still there.

> I wonder if there is something wrong with NM here as it doesn't even
> seem to be even managing my wired connections:

IIRC on Ubuntu (and perhaps Debian?) if you have anything in
/etc/network/interfaces, then the distro configures NM to ignore those
interfaces.  I think if you remove anything related to eth0 from /e/n/i
then NM will be able to manage them.

Dan

> root@bionic-newport:~# ifconfig
> eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
>         inet 172.24.25.23  netmask 255.240.0.0  broadcast
> 172.24.255.255
>         inet6 fe80::2d0:12ff:fe0f:f583  prefixlen 64  scopeid
> 0x20<link>
>         ether 00:d0:12:0f:f5:83  txqueuelen 1000  (Ethernet)
>         RX packets 66096  bytes 18460509 (18.4 MB)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 3726  bytes 299073 (299.0 KB)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>
> lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
>         inet 127.0.0.1  netmask 255.0.0.0
>         inet6 ::1  prefixlen 128  scopeid 0x10<host>
>         loop  txqueuelen 1000  (Local Loopback)
>         RX packets 58  bytes 5562 (5.5 KB)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 58  bytes 5562 (5.5 KB)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>
> root@bionic-newport:~# cat /etc/network/interfaces
> # ifupdown has been replaced by netplan(5) on this system.  See
> # /etc/netplan for current configuration.
> # To re-enable ifupdown on this system, you can run:
> #    sudo apt install ifupdown
> allow-hotplug eth0
> auto eth0
> iface eth0 inet dhcp
>
> root@bionic-newport:~# nmcli device status
> DEVICE    TYPE      STATE      CONNECTION
> can0      can       unmanaged  --
> eth0      ethernet  unmanaged  --
> eth1      ethernet  unmanaged  --
> eth2      ethernet  unmanaged  --
> eth3      ethernet  unmanaged  --
> eth4      ethernet  unmanaged  --
> lo        loopback  unmanaged  --
> cdc-wdm0  modem     unmanaged  --
>
> Instead on xenial I get:
> root@xenial-newport:~# nmcli --version
> nmcli tool, version 1.2.6
> root@xenial-newport:~# nmcli device status
> DEVICE    TYPE      STATE         CONNECTION
> eth4      ethernet  connected     Wired connection 1
> cdc-wdm0  modem     disconnected  --
> eth1      ethernet  unavailable   --
> eth2      ethernet  unavailable   --
> eth3      ethernet  unavailable   --
> can0      can       unmanaged     --
> eth0      ethernet  unmanaged     --
> lo        loopback  unmanaged     --
>
> By the way, thank you again for your modemmanager PPA's, they are
> doing wonders for us ARM/ARM64 users!
>
> Regards,
>
> Tim
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