Zephyr controller unable to discover characteristics after a while

[bds]

I'm using a NRF52DK with Zephyr controller build attached to Bluez 5.45 to scan, connect and discover characteristics on up to 16 devices in parallel. While testing, everything seems to run fine for a few minutes, until characteristics discovery stops working. From the attached HCI snoop file, I'm quite sure that scanning and connection setup is still working fine, but ATT packets are not being received anymore. More specifically: at some point there is no response to the MTU request packet just after setting up the connection. I'm also sure the problem is not related to the peripherals (also NRF52 based), since the only thing that helps to resolve the problem is restarting (power cycling) the Zephyr board.

Any ideas or similar observations?

hci.snoop

.config

mynewt.snoop

[Carles]

Hi there,

I recall seeing something similar earlier this summer, but it was solved.

Can you specify which version of Zephyr you are running? Is it 1.8, 1.9 or master? Also this could be the Segger USB to UART bridge, make sure your MSD is disabled as per these instructions:

www.zephyrproject.org/.../nordic_segger.html

Thanks,

Carles

[bds]

I was using the master. I doubt it's the Segger USB to UART, as connection setup and advertisements still worked fine (also see HCI log). Using myNewt Nimble seems to work better at the moment...

[Carles]

Yep sorry, I did not realize. That said I would still recommend disabling the MSD. Can you let us know what firmware your peripherals are using in order to eliminate possibilities?

[bds]

Our peripherals are a design based on the nrf52, running a firmware based on your ble uart example. I'm pretty sure it's not the peripherals though. Because, without touching the peripherals, everything works again as soon as I reset the controller. Also, with Nimble, I don't have the same problem.

[Carles]

OK Thanks for the info. We will need to try and reproduce the issue to find out what is going on.