+CEREG signals denied before being registered

Sven Schwermer sven at svenschwermer.de
Thu Oct 20 09:44:59 UTC 2022

On 10/20/22 11:16, Aleksander Morgado wrote:
>> There is probably no generic way to resolve this because the current
>> implementation seems correct. But do you have guidance how to fix this
>> with - perhaps with a non-upstreamed patch? Perhaps, we could start a
>> timer when getting the denied status update and wait some time for the
>> registered state update before returning with a failed state?
> Yes, that is an option. But how much would you say you want to wait?
> 5s, 10s, 15s?
> Maybe this logic could be upstreamed, but we would need to understand
> what happens in other cases, e.g. what do MBIM and QMI modems report
> under the same scenario?

I have done some extensive testing with the Fibocom MA510-GL triggering 
automatic registration using +COPS=0 in a loop over many hours and days. 
In most cases, we get the +CEREG: 3 -> +CEREG: 5,... transition within 
10 seconds.

I'll experiment a little with this and post back to this thread when I 
have come up with a satisfactory workaround. Then we can discuss the 
upstream-ability :)

Best regards,

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