Re: AW: pppd gets no IP during dial-in with Sierra MC7710 qmi

[Dan Williams <dcbw redhat com>]

On Mon, 2013-03-11 at 08:50 +0100, Bjørn Mork wrote:
> Andreas Schigold <andreas schigold blankom de> writes:
>
> > > Marius Kotsbak <marius kotsbak com> writes:
> > > > Den 08. mars 2013 14:59, skrev Bjørn Mork:
> > > > > Marius Kotsbak <marius kotsbak com> writes:
> > > > > > Den 08. mars 2013 13:07, skrev Bjørn Mork:
> > > > > > > > Or does it working just with the QMI-WWAN driver via the 
> > > > > > > > /dev/cdc-wdm
> > > > > > > > > file? To make the libqmi useable makes a lot of work since I need 
> > > > > > > > > some other libs as prerequisite for this. At this moment they are 
> > > > > > > > > not included in the buildroot-project.
> > > > > > > The MC7710 is fully usable with PPP so you don't need QMI if you 
> > > > > > > can live with the speed penalty.
> > > > > >
> > > > > > My experience is that it does not work with just AT commands when it 
> > > > > > is in QMI mode, so I would instead look into libqmi.
> > > > >
> > > > > PPP works fine in QMI mode. AT!SCACT etc does not.
> > > >
> > > > I refer to usage of Network-/Modem manager. It might be that they use 
> > > > some features not available in QMI mode.
> > >
> > > Ah, right, I should check the context before replying :)
> > >
> > > Bjørn
> >
> > Now you lost me :(
> > Should pppd with AT-commands can connect with this modem and firmware or can't it?
>
> ppp can connect, but maybe not with ModemManager.  I'll have to trust
> Marius on that.  Haven't tried...

Currently with ModemManager, if we have a device that is driven by
sierra_net or qmi_wwan, then MM expects that the network port is usable,
and will not try PPP.  That's because sierra_net and qmi_wwan provide
the ethernet interfaces, and those should always be used in preference
to PPP as they are more reliable.  (note, secondary bearers, when we get
them, will use PPP in many cases)

So basically if you're using ModemManager, you either:

1) use QMI/sierra_net and figure out why the ethernet port isn't
working, because it should be working

or

2) remove the QMI and Sierra plugins and let the Generic plugin handle
the device, which will only use PPP

Dan

> > If it can't work:
> > Do I need definitively libqmi or must the gobi-lib work too?
> >
> > I know the network-manager from my Debian-desktop-PC. But at this
> > embedded system I have no X-server. Is it working too? Or do I have to
> > analyze the source to develop my own programm?
>
> NetworkManager and ModemManager are dbus-based daemons and should work
> fine on embedded systems.  See e.g Aleksanders work on OpenWRT:
> http://sigquit.wordpress.com/2013/02/14/modemmanager-and-latest-udev-in-openwrt/
>
> > Another question: Is it important for dialin-procedure if I have an
> > access-point with LTE or UMTS? Or does it no matter? - except speed of
> > course ;)
>
> Does not matter.  The firmware hides the configuration differences.
> You'll see them if you start messing with the radio network QoS
> settings, but most users won't care about those.
>
> > Speed is the second goal. The first goal is to get it working. At this
> > moment we use the AT91Sam9G20 which have just USB 1.1. The plan is to
> > upgrade later to the ~G25 with USB 2.0. Only then a faster solution is
> > needed, but then we have more time.
>
> In my very limited experimenting I could never get more than ~8Mbits/s
> uplink with PPP.  I get >30 Mbits/s up using the same MC7710 card with
> any of the supported network interface protocols (DirectIP, QMI, MBIM).
>
>
> Bjørn
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