U-Blox modem reconnect

[Alexander Smirnov <asmirnov@ilbers.de>]

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Dear all,

could you please help me with the following issue. I use U-Blox 
SARA-U270 modem. I'm able to online it and connect to GPRS using both: 
connman and ofono-tests. The problem occurs when modem loses GSM link.

What I did:

  - Boot board with ofono 1.18
  - activate-context & process-context-settings
  - ifconfig shows ppp0, everything works
  - Disconnect physical GSM antenna, network strength becomes 0 (in 
list-modems)
  - Connect antenna, network strength becomes 40

Problem:

  After these steps, modem doesn't reconnect to GPRS, while 
list-contexts shows correct settings:

[ /ublox_0 ]
     [ /ublox_0/context1 ]
         Username = t-mobile
         AuthenticationMethod = chap
         Protocol = ip
         Name = Internet
         Settings = { Interface=ppp0 Netmask=255.255.255.255 
Method=static DomainNameServers=10.74.210.210,10.74.210.211, 
Address=10.23.6.118 }
         IPv6.Settings = { }
         Active = 1
         AccessPointName = internet.t-mobile
         Password = tm
         Type = internet

But I don't see ppp0 interface.

An attempt to activate-context doesn't do anything, just empty output 
(with enabled debugging).

Attempt to deactivate-context failed with:

Error deactivating /ublox_0/context1: 
org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible 
causes include: the remote application did not send a reply, the message 
bus security policy blocked


The only hard modem reset helps.

Moreover, after antenna disconnect, there is no more cellular service in 
ConnMan. Only daemon restart helps.


How should I handle lose GSM network events to keep ppp0 up? Why ofonod 
hangs with the steps mentioned above?


-- 
With best regards,
Alexander Smirnov

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