Clarification on ModemManager Reconnection Behavior

[Armand Daussà]

Hi,

We’ve encountered an issue with modem disconnections and have reviewed the
ModemManager logs to better understand the behavior. What we observed is
that after a disconnection, ModemManager attempts to reconnect but then
shuts down and does not attempt to reconnect again. It only resumes
connection attempts after the operating system is rebooted.

In situations where the modem experiences issues and cannot establish a
connection, ModemManager appears to stop trying entirely until the next
system reboot. Eventually, after a reboot, ModemManager is able to
successfully initialize the modem and re-establish a connection.

Could you please confirm if this is the expected behavior? If not, is there
a recommended way to ensure that ModemManager continues trying to reconnect
without requiring a system reboot?

Is it something fixed in more recent releases?

Key timestamps:
16:37:24 -> Modem sends* '<CR><LF>+SIMCARD: NOT AVAILABLE<CR><LF>'*
*Five OS Reboots are performed*
19:19:21 -> Modem manager starts following last reboot and a successful
initialization is completed

Logs are attached.

Thanks in advance!

*System info:*
*OS: *
Linux fonts1 6.1.21-v8+ #1642 SMP PREEMPT Mon Apr  3 17:24:16 BST 2023
aarch64

> PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"
>

*Hardware *

> manufacturer: QUALCOMM INCORPORATED
> model: 0 (doesn't show but its a SIMCOM S2-107EQ)
> firmware revision: LE11B12SIM7600M22
> carrier config: ROW_Gen_NonVoLTE
> carrier config revision: 05010813

h/w revision: 10000
> supported: gsm-umts, lte
> current: gsm-umts, lte


*ModemManager version*
1.14.12
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