gprs_llc_process_xid_ind() does not echo L3_PAR, breaks PDP activation for Motorola KRZR
(at the time of writing) http://cgit.osmocom.org/osmo-sgsn/tree/src/gprs/gprs_llc.c#n227
We check if (xid_field->type != GPRS_LLC_XID_T_L3_PAR)
before echoing the XID to the MS
The Motorola KRZR responds by sending the XID list again and repeats 4 times before giving up and sending PDP deactivate context, with a cause 25 "LLC or SNDCP Failure"
Removing the check for xid_field->type != GPRS_LLC_XID_T_L3_PAR and echoing the L3 parameter back results in PDP activation success and GPRS session works.
Why this check? Why do we not echo all the xid fields back? Did it break with some other phone?