Created attachment 136518 [details]
Modem and Network Manager Debug Logs
I am using NM and MM on my Raspberry Pi 3 (debian:stretch) with a "Industrial" Huawei M2M 3G Modem (MS2131I-8).
I have come across an issue where the modem does not connect at what appears to be the last stage i.e. establishing the ppp interface. However if I physically remove the modem and re-plug the modem (sometimes a few times) it eventually connects (and sometimes disconnects awhile later). Please could you advise what the issue could be?
I have attached both NM and MM debug logs. I started MM and then NM.
Upon closer log file inspection, it appears that the interface on ttyUSB2 enters a hung state after the first connection attempt:
(ttyUSB2): --> 'ATD*99***1#<CR>
(ttyUSB2): <-- '<CR><LF>CONNECT 21600000<CR><LF>'
after this it appears that all AT commands return with:
'Sending command failed: 'Resource temporarily unavailable''
When the modem was in the stuck state, I tried using the mmcli reset command which actually hung the entire computer.
Anyways, I'm now tending towards thinking this may be a Network Manager issue with establishing/creating the PPP interface?
(In reply to quickprototype from comment #1)
> Upon closer log file inspection, it appears that the interface on ttyUSB2
> enters a hung state after the first connection attempt:
> (ttyUSB2): --> 'ATD*99***1#<CR>
> (ttyUSB2): <-- '<CR><LF>CONNECT 21600000<CR><LF>'
> after this it appears that all AT commands return with:
> 'Sending command failed: 'Resource temporarily unavailable''
Well, the "hung state" could very well be that the modem is connected :) After that any other AT command sent to the port would timeout.
(In reply to quickprototype from comment #2)
> When the modem was in the stuck state, I tried using the mmcli reset command
> which actually hung the entire computer.
> Anyways, I'm now tending towards thinking this may be a Network Manager
> issue with establishing/creating the PPP interface?
Is this a self-compiled NM? Did you build with PPP support?
Interesting, I did not know the modem stops responding to AT commands in the connected state. I assume this is why multiple "ports" are sometimes available with modems to allow for simultaneous SMS, USSD etc.
NM and MM is not Self compiled, it is both the default standard versions that come with the Raspberry Pi sudo apt-get repos (1.6 line)
I have been trying to compile a later version but so fat I've failing miserably.
For interest sake my attempt at compiling from source is detailed here:
Please could you maybe advise which --enable flags are relevant for 3G connectivity? I only added --with-modem-manager-1
I've finally compiled Network Manager to the 1.8 line with MM still on 1.6.
The issue unfortunately still persists. In that connectivity is not maintained.
-- GitLab Migration Automatic Message --
This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.
You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/mobile-broadband/ModemManager/issues/34.