On 18/08/2020 6:27 pm, Aleksander Morgado wrote:
Hey,
I'm using a Quectel EC21 modem on a Debian Buster Linux system (using
modemmanager 1.10.0).
Please note, MM 1.10.0 is a very very old release, no longer
supported, and it's not even the last one inthe 1.10.x series...
Fair enough, but 1.10.0 is comes with Debian Buster, which is the latest
Stable release of Debian. However there is a backport of 1.14, from the
Unstable (next release) distro, for Buster.
1.10.0 was released in 2019-01-17, and after that there have been 4
new updates in the 1.10.x series (1.10.2 on 2019-06-10, 1.10.4 on
2019-07-04, 1.10.6 on 2019-09-12, 1.10.8 on 2019-10-30. Then we have
had the whole 1.12.x series up and running (7 releases); 1.12.0 was
released on 2019-11-06 and the last 1.12.12 was released on
2020-06-23. 1.14.0 was released on 2020-06-23. You should probably
poke Debian Buster packagers of ModemManager... they are 12 releases
late in their latest stable release ;)
I guess it's a policy thing with Debian, where they choose stability
over the latest and greatest, once a new distro is released. All new
development goes into the unstable distro, with backports from unstable
to stable when necessary.
Since they have a backport for mm 1.14 I can't be critical of Debian
being out of date (and I'm someone who tends to be lured by the latest
and greatest shiny things ;-) )
This may be a known issue with QMI modems where the internal network
registration attempt is done with "QMI NAS Register In Network"; this
command not only registers in network, it also makes the access tech
preference fallback to "any", and MM doesn't consider that in its API.
There is a recent patch to avoid this, by avoiding the use of "NAS
Register in Network" and use "NAS Set System Selection Preference"
instead:
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/commit/c70b3557184fdf1472ff0cb36e9fd937cc7f9024
That patch is not yet in any release, though, not even in 1.14.0. I'll
backport it to the 1.14.x branch so that it gets into 1.14.2.
You can confirm that this issue is happening to you by running this
command once the tech went back to the one you didn't want:
$ qmicli -d /dev/cdc-wdm0 -p --nas-get-system-selection-preference
Here is the output.
# qmicli -d /dev/cdc-wdm0 -p --nas-get-system-selection-preference
[/dev/cdc-wdm0] Successfully got system selection preference
Emergency mode: 'no'
Mode preference: 'umts, lte'
Band preference: 'wcdma-2100, wcdma-850-us'
LTE band preference: '1, 3, 5, 7, 28'
TD-SCDMA band preference: '(null)'
Roaming preference: 'any'
Network selection preference: 'automatic'
Service domain preference: 'cs-ps'
GSM/WCDMA acquisition order preference: 'wcdma'
Acquisition order preference: lte, umts, gsm, td-scdma,
cdma-1x, cdma-1xevdo
What are the key indicators that confirm the issue?
Network selection preference: 'automatic'???
Acquisition order preference: lte, umts, gsm, td-scdma,
cdma-1x, cdma-1xevdo???
Mode Preference (umts + lte) already tells you that the setting was
reseted (assuming you requested 3G-only).
The SSSP patch in network registration will very very likely solve
your problems.
ok. I will attempt one of the following.
- try to apply the patch to debian buster sources (1.10.0) and rebuild a
new package.
- try to apply the patch to debian buster backport sources (1.14.0) and
rebuild a new package.
- wait for a 1.14.2 release and poke the debian backport maintainer to
generate a new release.
Thanks, Brendan.
_______________________________________________
ModemManager-devel mailing list
ModemManager-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel
