Problems to get valid location data with Sierra Wireless MC7455

Ulrich Ölmann u.oelmann at
Mon Sep 24 10:09:27 UTC 2018

Hi Aleksander,

Aleksander Morgado <aleksander at> writes:
>> > [...] 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).

Best regards
Pengutronix e.K.                           | Ulrich Ölmann               |
Industrial Linux Solutions                 |  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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