NRF9160 Modem Frozen after put into Offline Mode

RE: NRF9160 Modem Frozen after put into Offline Mode

lobaro-theo — Tue, 21 Jan 2020 17:12:56 GMT

Hello Sigurd,

thank you for your reply.

We will further investigate on this. We close the UDP socket before CFUN4 but two AT Sockets are still open:

1) for interactive AT command usage

2) for out of band indications from AT commands

We will also try to close this two sockets and see if this helps.

Theo

RE: NRF9160 Modem Frozen after put into Offline Mode

Sigurd — Mon, 20 Jan 2020 15:45:09 GMT

We have not been able to reproduce this issue with NCS 1.1.0

[quote userid="79239" url="~/f/nordic-q-a/56167/nrf9160-modem-frozen-after-put-into-offline-mode/229187"]Any UDP sockets are NOT closed before using CFUN=4 will be reused after wakeup in our implementation[/quote]

Try closing all the UDP sockets before using CFUN=4

RE: NRF9160 Modem Frozen after put into Offline Mode

lobaro-theo — Wed, 15 Jan 2020 10:42:42 GMT

RE: NRF9160 Modem Frozen after put into Offline Mode

lobaro-theo — Wed, 15 Jan 2020 10:41:47 GMT

Hello,

we observed the same problem with modem FW1.1 and might supply some more information to find the issue:

In our test setups the issue occurs quite seldom: once every 5-10 days or so with daily NB.IoT UDP socket uploads + CFUN=4 after jobs are done.

Looking at the connection log of our provider (1NCE.com) we see that the connection will simply not closed by the not returning CFUN=4 command. So CFUN=4 does not return and not iniate any connection disconnect on provider side. After some time (2h in our example case) the connection gets closed by the provider but the nRF9160 AT socket waits forever. Any UDP sockets are NOT closed before using CFUN=4 will be reused after wakeup in our implementation - this works most of the time.

In our real implementation we use timeouts on waiting on the AT socket and so we know that the modem power domain flag is set to OFF (NRF_POWER->POWERSTATUS) after CFUN4 did timeout.

For us it looks like the modem fw seems to "forget" to work on CFUN=4 and does consequently not answer to the AT command - BUT the modem power domain gets turned off..

Hope this helps the modem devlopers to track down the issue.

Greetings
Theo

P.S.:
The problem was using BSD Lib 0.5.0 and our own NON ZEYPHER freeRTOS based interface. So the above mentioned pull request has no relevance to us.

RE: NRF9160 Modem Frozen after put into Offline Mode

Sigurd — Fri, 10 Jan 2020 13:08:11 GMT

[quote user="mlang3440"]Do you know what part of the NCS code base was the cause of this?[/quote]

The issue in the post you linked to, was fixed as part of this PR: https://github.com/NordicPlayground/fw-nrfconnect-nrf/pull/1242

[quote user=""]some situations where putting the modem into offline mode[/quote]

How often does this happens ?

Could you upload the log output from LTE-Link monitor when the issue happens?

RE: NRF9160 Modem Frozen after put into Offline Mode

mlang3440 — Wed, 08 Jan 2020 16:15:25 GMT

We are using NCS 1.1.0. Do you know what part of the NCS code base was the cause of this?

RE: NRF9160 Modem Frozen after put into Offline Mode

Sigurd — Mon, 06 Jan 2020 15:41:21 GMT

Hi,

As mentioned by Håkon here, this was an issue with the NCS codebase. Let me know if updating your codebase to NCS v1.1.0 does not fix the issue.