I am trying integrate a GPRS modem in Android 6.0.1 without success. Modem works well at hardware level and answer correctly AT commands. In Android UI I only see SIM card not present and nothing related to modem works.
In Android log I can see a lot of subId=-2, phoneId=-1, slotId=-1, I think my problem is because of this wrong numbers.
Someone with experience in Android RIL could help me to understand how this numbers are generate and where?
I think my reference-ril.c is OK, and I can't understand why this Id are not generate correctly.
In almost all the case PhoneId equals slotId, it means which SIM card slot the current subscription is on. SubId maintain a record for SIM cards that have been inserted. eg, You insert a card with Iccid 46332223***3232 and the telephony record it as a subId=1, for another card with Iccid 46332223***9900, telephony record it as SubId=2.....Next when you insert 46332223***3232 again, telephony will know it's an acquaintance card, and SubId will again set as subId=1. So it's for other cards.
If SIM card is not presented, pls first check the GET_SIM_STATUS in your log, if the state is absent, you should check the modem part.