I have this old phone, a Samsung E3210B pre-Android feature phone that I
wish to use as a fallback option when (more frequently than I would
like) my broadband internet service goes down. When using ModemManager
1.18.x, I could plug in this phone, and it would expose a single
/dev/ttyACM0 port for all interactions including AT commands and PPP.
Then ModemManager could connect to the internet using the port as
normal, using the "generic" plugin. Now, using ModemManager 1.20.6 under
Fedora 39, the same phone fails (with a timeout) to establish a
connection using ModemManager. However, it does setup a proper
connection using wvdial from the command line, even under Fedora 39.
After a while, I managed to perform a git bisect on the code, and
pinpointed the first commit that breaks my phone, to commit
213cd81b3ade35024e2d702e2726273f00344185 "iface-modem-simple: wait for
packet service 'attach' state in ConnectionStep". However, I am now at a
bit of a loss at understanding the supposed purpose of this commit. Full
details are at this bug report:
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/743
The patch no longer cleanly reverts under 1.20.x, so I cannot just rip
it off...
