Hey, > I'm troubleshooting a problem with the Fibocom L610 LTE Cat-1 modem and > ModemManager 1.18.6. The modem/SIM appears to connect PDP context 0 > automatically. The APN seems to be populated from the SIM. When trying > to connect, ModemManager searches for the best context. If context 0 > matches our desired configuration (which it did in my case), it will try > to reuse it. However, +CGACT will not report the status of context 0. > Neither will +GTRNDIS allow to establish an ECM connection on context 0. > This confuses ModemManager. Some SIMs seem to allow establishing an > additional (identical) PDP context (e.g. with context ID 1), some don't. > The log of the connection attempt follows down below. > > I'm wondering if mm_3gpp_profile_list_find_best should restrict the > returned context ID to be within min_profile_id and max_profile_id. The > modem reports a minimum of 1 so that would prevent ModemManager to use > context 0. >
If I'm not mistaken, in Intel chipset based modems, CID=0 is used to handle the initial default EPS bearer; i.e. the bearer that gets automatically setup when the modem gets registered in the network. If +GTRNDIS isn't able to handle attempting a connection over that bearer, we should definitely try to use CID>=1 instead. This is probably something to handle in the Fibocom plugin itself. -- Aleksander https://aleksander.es
