Problems to get valid location data with Sierra Wireless MC7455

Aleksander Morgado aleksander at
Mon Sep 24 16:53:45 UTC 2018

> >> > [...] Do you have the GPS specific antenna connected to the module? Do
> >> > you have good satellite coverage?
> >>
> >> The GPS specific antenna is connected to the module and hopefully the
> >> satellite coverage is sufficient (my mobile phone tells me that it sees
> >> 10/27 satellites if it is held next to the GPS antenna). So I assume
> >> that perhaps there is some technical problem with respect to the antenna
> >> which should be excluded before further suspecting the software setup.
> >>
> >
> > Try to go outside with the hardware and get a clear sky view. If that
> > doesn't help either, there may really be a problem with the antenna
> > setup.
> as it did not help to have the antenna outside with a direct view to the
> sky I again thought about what could be wrong with my setup. Asking
> myself how to get the number of satellites the module sees I ended up
> at libqmi and hopefully tried to do the right thing here:
>     root at MP:~ qmicli --device=/dev/cdc-wdm0 --loc-get-gnss-sv-info
>     [01 Feb 2018, 02:24:11] -Warning ** [/dev/cdc-wdm0] requested auto mode but no MBIM QMUX support available
>     error: couldn't create client for the 'loc' service: CID allocation failed in the CTL client: Transaction timed out
> Could this be the root of my problems: not having configured libqmi with
> QMI over MBIM QMUX service? (Although I thought I did it correctly - but
> perhaps there is a quirk in my build system here that I would like to
> debug if you give me a positive answer).

No, that's not it, you probably don't require QMI over MBIM here if
your device is already using QMI.

Try to add a "-p" to that qmicli command you're using. Looks like you
may be trying to run QMI commands while other process (ModemManager?)
is also using the port. Using "-p" will direct your QMI messages
through the "qmi-proxy" that MM should have launched.


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