Just for closure since this thread appears high up in google search for "sim5320 cmux problem"...
I got the cmux functionality of the SIM5320 module working reliably, outside ofonod, but the answer would apply there (and elsewhere). The key is to set the cmux line discipline mtu to 120 bytes (or possibly as high as 127 bytes). When the cmux is activated and pppd is spawned on one of the virtual serial ports, certain network packets want to send a big chunk of data into the TX pipleline, and the SIM5320 cmux support can't handle it. The sim5320 never sends more than 120 bytes at a time to the virtual serial ports, so that was a clue right there... mtu 120 works, up to 126 works. I didn't try 127, but mtu set to 128 and higher fails. -Dave On 3/8/16, David Ashley <[email protected]> wrote: > Well this project seems to be dead. Anyway for what it's worth, the > problem turned out to be some difference between the AT+CMUX behavior > betwene the sim900 and the sim5320 module. When I tore out all the MUX > related code the 3G / internet / ppp aspects all just start working. > > -Dave > > On 3/7/16, David Ashley <[email protected]> wrote: >> Hello, I'm at my wits' end trying to get ofono working with the >> sim5320 module. I'm using the plugins/sim900.c module as a starting >> point. I think the issue has something to do with the difference >> between the MUX functionality between the 900 and the 5320. > _______________________________________________ ofono mailing list [email protected] https://lists.ofono.org/mailman/listinfo/ofono
