> -----Original Message----- > From: Dan Williams [mailto:[email protected]] > Sent: Thursday, April 05, 2018 1:22 PM > To: Matthew Starr; [email protected] > Subject: Re: u-blox TOBY-R200 Intermittent Long Registration on Simple > Connect > > On Tue, 2018-04-03 at 21:19 +0000, Matthew Starr wrote: > > I have a u-blox TOBY-R200 running on an embedded Linux device with the > > ModemManager 1.8-rc2 build, plus the patch for "ublox: fix 'any' > > mode building". On this device there seems to be an issue between the > > automatic registration of the TOBY-R200 modem and ModemManager > > reaching the Simple Connect State (5/8) Register. > > > > Between reboots I can get ModemManager to have a quick registration > > and then have a slow (40 or more seconds) registration, where > > ModemManager seems to have caught the modem right before it finished > > auto registration or for some reason a denied state occurs and > > restarts the entire registration over. The issue seems to happen > > right before simple connect state (5/8) Register is run. > > > > Here is what is reported during a quick registration step: > > Simple connect state (5/8): Register > > Already registered in network 'XXXXXX', automatic registration not > > launched... > > > > Here is what is reported during a slow registration step: > > Simple connect state (5/8): Register > > Launching automatic network registration... > > > > See attached files for logs of the fast and slow registration from the > > start of a simple connect to step (6/8) Bearer > > In the quick case, the modem is already registered long before > SimpleConnect gets to it's registration check. > > In the slow case, the modem isn't yet registered. It first reports > GPRS=denied, UMTS=denied, LTE=idle. MM then starts automatic > registration on ACM0 and two seconds later gets GPRS=registered on ACM1. > But ACM0 is still blocked running the AT+COPS=0 registration command > which doesn't complete until 30 seconds later. Only then can MM continue > with the connection attempt, even though the modem was registered 28 > seconds before. > > So yeah, it's (1) a race with modem firmware between the two cases, and > (2) the modem not returning from the AT+COPS=0 automatic registration > request even when it has already registered. (though there is perhaps > another small race where if the modem has just registered the instant > before MM sends AT+COPS=0 and hasn't yet notified MM, it will then do a > full network scan and registration cycle when the +COPS=0 comes in) > > How long has the modem been +CFUN=1 before you send the > SimpleConnect() request? Can you test whether waiting a couple seconds > after the modem is fully enabled, before sending SimpleConnect(), makes a > difference? > We could also test-patch MM do that. This isn't a real fix though... > > Dan >
Dan, I am using SystemV init scripts for my init this device and I already tested putting in various sleeps right after starting ModemManager before I start NetworkManager which is setup to autoconnect to the cellular connection. I put in a sleep as long as 30 seconds before NetworkManager is started and the rest of the boot continues and it made no difference. I was still getting random results with sometimes MM seeing auto registration had already completed and other times it forcing a full registration. Matt > > Any idea on what the difference is between the fast and slow > > registration and what might be causing it? Any ideas how to fix it? > > > > Best regards, > > Matthew Starr > > > > > > _______________________________________________ > > ModemManager-devel mailing list > > [email protected] > > https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel _______________________________________________ ModemManager-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel
