CoAP client sample - send command freezes after a few iterations

[Lukáš]

Hi,

as discussed in different issue on DevZone. We have discovered that send command freezes the program in the CoAP client sample. The Nordic employee Hakon has confirmed that it also happens on his board.

Could you please try to inspect the issue? Unfortunately, we are not able to collect the modem trace right now our DK broke up and we are not able to collect traces on our custom board.

The modified sample could be downloaded under this link: devzone.nordicsemi.com/.../coap_5F00_client.zip

[Hakon]

Hi there,

I will report this internally as a potential bug. Some delay in response time is to be expected as many staff members are still on vacation.

[Lukáš]

Hi Hakon, I know that many your collegues are still on vacation. But could you please try to push this issue? It is something that we reported already month ago and in our app, it is critical issue because it freezes the whole device. And it is not possible to recover. 

[Lukáš]

Heidi, I apologize for putting the pressure on you. However, is there anything we can do to speed up the process? For us, it is now a blocker issue because the whole app freezes and then the device couldn't be used.

[Heidi]

Hi, I understand. The person responsible for the CoAP client sample isn't back from vacation until Monday the 17th, but I will try to find someone else who can take a look at this.

I believe taking a modem trace would be the best course of action. What is the reason you aren't able to take one on your custom board? Perhaps we can work around it. 

[Lukáš]

Hi, I think that this has nothing to do with the CoAP client sample. It is more likely bsdlib issue (see the note about blocking and non-blocking options).

Heidi said:

What is the reason you aren't able to take one on your custom board? Perhaps we can work around it. 

We would be very happy if we could capture the modem trace. However, we have not found a solution on how to do this on our custom board. The trace from nRF9160 could be gathered only on UART. 

In our setup, we use nRF9160 and nRF52820 that are wired via one UART interface, so we don't know how to pass the trace through it without completely rewriting the application. If there would be an interface from Nordic on how to save the trace to the internal/external flash, so it could be sent via Bluetooth/LTE afterward, it would greatly help us.

[Lukáš]

Hi Heidi, could someone please finally inspect this issue? Its already 2 months ago since we reported it first here https://devzone.nordicsemi.com/support/251815#permalink=575323. It is something in BSDlib which we cannot fix on our own and the device is not usable without the fix. Thanks

[Heidi]

Hi

Yes, there is somebody assigned to inspect this issue from the bsdlib team.

We are really sorry for the wait, but this is to be expected during the summer holiday season in Norway. I will let you know as soon as I have any news.

Best regards,

Heidi

[Lukáš]

Could we at least know the cause or workaround? Our app on the device randomly freezes, which means it is unusable, and we have not been able to get any solution/fix for two months. To be honest, I am quite disappointed.

[Heidi]

Hi, I completely understand that this has taken a long time. Unfortunately, this is to be expected during summer. The developers have a lot of other cases, just like yours, to look into at the same time. 

They will run the sample and confirm that this is, in fact, a bug, and then try to provide you with a workaround.

Best regards,

heidi

[Lukáš]

So in the meantime, could you please at least provide us your input on collecting the modem trace on custom boards?

Lukáš said:

We would be very happy if we could capture the modem trace. However, we have not found a solution on how to do this on our custom board. The trace from nRF9160 could be gathered only on UART. 

In our setup, we use nRF9160 and nRF52820 that are wired via one UART interface, so we don't know how to pass the trace through it without completely rewriting the application. If there would be an interface from Nordic on how to save the trace to the internal/external flash, so it could be sent via Bluetooth/LTE afterward, it would greatly help us.

[Heidi]

Hi again, so they took a look at the case. 

The reason it's freezing is because the received data is never read. So the buffers that the modem uses to send information to the application code fills up and then the modem can't even send the acknowledge message back to the application core when the application core tries to send a CoAP message.

If you add a read in the for-loop after the CoAP package is sent, it should run fine. 

Best regards,

Heidi

[Lukáš]

Hi Heidi,

We still have not been able to troubleshoot it in our main application. Seems like the example issue is a different one then we are experiencing in the main firmware. I am closing this as it is example related and I will open a new private issue where we will provide modem trace for analysis from our main firmware.

Thanks for your help.