Re: Problems with modems/Example config for QMI-based modem,

[Jakob Hasse <jakob hasse smart-home-technology ch>]

Hi Dan,

Sorry this was quite my bad. The SIM card was not activated in the 
backend system.
After activation, NetworkManager established a connection but I could 
not ping other systems, neither via domain name nor via ip directly. 
Right now I'm working on some urgent tasks but I will come back to you 
as soon as possible if I looked into that problem more deeply and 
gathered log files.

Thanks so far and best regards,
Jakob

On 14.03.2018 17:23, Dan Williams wrote:
> On Tue, 2018-03-06 at 12:01 +0100, Jakob Hasse wrote:
> > Hello Dan, thanks for the answer.
> >
> > On 28.02.2018 22:38, Dan Williams wrote:
> > > On Wed, 2018-02-28 at 18:40 +0100, Jakob Hasse wrote:
> > > > Hello,
> > > >
> > > > We want to integrate different modems into our embedded system.
> > > > Recently, our Linux-distributor decided to introduce
> > > > NetworkManager.
> > > > When we switch to NetworkManager, network connectivity via 3G/2G
> > > > is
> > > > never reliable: the connection either succeeds only sporadically
> > > > or
> > > > not
> > > > at all. This happens on three types of modems from two different
> > > > vendors. When we set up the modems manually with pppd or with a
> > > > QMI
> > > > test
> > > > program, everything works fine an reliably, also automatically
> > > > after
> > > > boot.
> > > > Could you give me advice what steps to do to produce debug/log
> > > > output
> > > > to
> > > > then come back here and have someone look at it?
> > > You want to increase the NetworkManager and ModemManager logging
> > > level:
> > >
> > > nmcli g log level debug
> > > mmcli -G debug
> > >
> > > and then plug your modem in.  This will dump debug logging to
> > > whatever
> > > system log service your linux distro uses.  For systemd-based
> > > distros,
> > > you want:
> > >
> > > journalctl -b -u NetworkManager
> > > journalctl -b -u ModemManager
> > >
> > > other distros will use /var/log/messages, /var/log/daemon.log, or
> > > wherever else syslog 'daemon' facility output goes.
> > >
> > > > Furthermore, it would be really nice to have an example
> > > > configuration
> > > > file for /etc/NetworkManager/system-connections/ to configure a
> > > > modem
> > > > with QMI connection. All the examples I had so far (seem to) only
> > > > establish the connection with pppd.
> > > There should be no difference between a QMI or MBIM based modem and
> > > a
> > > PPP based one.  The only options you really need are the APN and
> > > possibly the username and password in the [gsm] section.
> > >
> > > Since your email address is ".ch" I'm going to assume you don't
> > > care
> > > about CDMA/EVDO and thus you only need to use [gsm].  The simplest
> > > connection would be something like:
> > >
> > > [connection]
> > > id=T-Mobile Internet
> > > uuid=0083942e-b260-4b73-a1fd-860f3e6ca2c2
> > > type=gsm
> > >
> > > [gsm]
> > > apn=epc.tmobile.com
> > > number=*99#
> > >
> > > Again, there should be no difference between QMI and PPP-based
> > > modems
> > > from a NetworkManager perspective.  ModemManager abstracts that
> > > away
> > > for us.
> > I attached the log of a successful run and an unsuccessful run.
> > NetworkManager was successful with a Telit UE-910-UED (3G) and
> > unsuccessful with a Quectel BG96 (LTE Cat M1/2G). In the latter
> > case,
> > the modem was registered in the network, according to he Manual and
> > the
> > LED feedback. ModemManager recognized the modem as it printed me
> > output
> The call for the Quectel is failing due to:
>
> eQMIWDSCallManagerCallEndReasons_InvalidSIMState
>
> which suggests something wrong with the SIM.  Does the same SIM work in
> another device?
>
> I do wonder about these errors:
>
> Mar  6 08:26:31 ccimx6uluvalue daemon.warn ModemManager[775]: <warn>  couldn't load SIM identifier: 'Couldn't 
> get UIM ICCID: QMI protocol error (94): 'NotSupported''
> Mar  6 08:26:31 ccimx6uluvalue daemon.warn ModemManager[775]: <warn>  couldn't load IMSI: 'Couldn't get UIM 
> IMSI: QMI protocol error (94): 'NotSupported''
>
> Maybe Aleksander knows more about this?
>
> Dan
>
> > with mmcli -m 0. But no Internet connection so far.
> > Normally, we also had problems with the Telit modem, I don't know why
> > it
> > worked yesterday... So far it was completely random for me, I could
> > see
> > no correlation of time or place or configuration with successful
> > connections.
> >
> > I tried the Quectel modem with this system-connections file:
> >
> > [connection]
> > id=cellular
> > type=gsm
> >
> > [gsm]
> > apn=shared.m2m.ch
> > number=*99#
> >
> > [ipv6]
> > method=ignore
> >
> > Later I added a uuid and tried again without success, even though
> > the
> > connection to the Telit module which was successful also didn't
> > contain
> > a uuid.
> > > > Another problem is that it often happens that we use
> > > > NetworkManager
> > > > on
> > > > devices which changes some settings and afterwards we can't even
> > > > use
> > > > the
> > > > old methods to establish a connection. This is really scary since
> > > > it
> > > > basically renders our devices unusable so far. Is it possible to
> > > > tell
> > > > NetworkManager to put the device in the original state again
> > > > after
> > > > using it?
> > > What kind of changes happen here?  Are they things that are done
> > > externally, or done by NetworkManager?
> > We suspect NetworkManager but don't have evidence, maybe it's
> > something
> > else but the main change we do is that NetworkManager is installed.
> > Besides not being able to connect anymore, I noticed that the
> > connection
> > search mode of our Quectel modem changed, meaning it would search
> > LTE
> > Cat M1 and NB and 2G, not just LTE without 2G.
> > > > I also have a question to ModemManager but don't know whether I'm
> > > > right
> > > > with it here:
> > > > We want to send AT commands to the modems while they serve an
> > > > internet
> > > > connection. Normally, this is possible since the Modems all have
> > > > multiple serial interfaces. But when using ModemManager, it locks
> > > > all
> > > > serial interfaces of the modems and we can't use them anymore. I
> > > > know
> > > > that ModemManager can send AT commands with "mmcli --command" but
> > > > only
> > > > in debug mode, so apparently not for production use. Is it
> > > > possible
> > > > to
> > > > send commands another way with ModemManager or prevent it from
> > > > locking
> > > > all AT interfaces?
> > > Yeah, this request comes up periodically, and MM should probably
> > > just
> > > not open ports it doesn't need.  With PPP-based modems MM needs at
> > > least two AT ports (one for the PPP connection and a second to use
> > > for
> > > status while connected).  I don't think MM will care about the AT
> > > ports
> > > when it's using QMI/MBIM, but if you can get debug logs from
> > > ModemManager we can verify that.
> > >
> > > Dan
> > All the Best,
> > Jakob

--
Jakob Hasse
Software Developement

E: jakob hasse smart-home-technology ch
T: +41 44 552 02 66

Smart Home Technology GmbH
www.smart-home-technology.ch