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

[vich]

Hi bds,

I see in the snoop log, for example, first "connection failed to establish" at packet number 776, the host is trying to send ATT MTU request on a disconnected connection. This should be ok for the controller, as it will drop the data packet and not track it for num of complete packets. You will not get MTU responses for these disconnected connections. 776 56.021303 c3:71:31:b3:e8:fe () f7:11:72:f7:69:b5 (TP) ATT 11 Sent Exchange MTU Request, Client Rx MTU: 256

Do you see these "failed to establish connections" with mynewt?