Pairing errors with pc-ble-driver-js in one of our production locations

[Roiger]

Hi,
We have a typescript-based code running pc-ble-driver-js on a linux machine, with peripherals that are nrf52840 or nrf52833, which is a setup we have used with minimal side effects so far.
In one of our production locations, there is a peak in driver errors caused by pairing:

• There is a high number of NRF_ERROR_NO_MEM - I think "too" many of the peripherals are trying to pair at the same time, but I am unsure how we did not have this occur on bigger in-office stores. 1575 occurrences of this in the past 4 days.
• ​There is also this error which is recurring, which I have not seen before: "Error occured when replying sec params. Errorcode: Unknown value (0x8001)". 549 occurrences of this in the past 4 days. I think https://devzone.nordicsemi.com/f/nordic-q-a/16531/error-when-trying-to-pair-bond-to-a-peripheral-in-nrf-connect-v1-0-on-linux is similar, but no response. 0x8001 maps to, as is written, "unknown error".
• There is another less popular recurring error which I likewise have never seen before: "BLE Failed to decode event, error code is 9/0x9." 348 occurrences, always coupled with NRF_NO_MEM, in the past 4 days. Error code 9 seems to map to invalid length of response https://devzone.nordicsemi.com/f/nordic-q-a/11653/sdk-10-0-scanner-beacon-sd_ble_enable-returns-error-9.
• There is also an unusually large number of disconnects due to BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED - 19.5 K in the past 4 days. We are used to this happenng sporadically at the driver level, but not in such large quantities.

What is the cause of these errors?
Thanks!

Roi

[Hung Bui]

Hi Roi, 

It's hard to debug with just the error code and without the context, which function throwing the error code. 

We would need to know which exact function sending such error code. 

If you can reproduce the issue please try to debug and find the function. 

NRF_ERROR_NO_MEM may simply comes from the buffer to send data is full. For example when you try to queue too many packets to send in a write command/notification. 

BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED  is a common disconnection reason. It happens when the central sends a connect request but for some reasons (interference for example) it doesn't receive any response from the peripheral. 

[Roiger]

Hello Hung!
Generally - we receive NRF_ERROR_NO_MEM on authentication via mitm (pin code response to authkey request)

[Hung Bui]

Thanks for the info. But we need to know which exact function is returning the error. 
And it happened on the peripheral's side or on the central's side  ? 

[Roiger]

Central, via pc-ble-driver-js - the called function in the bindings is replyAuthKey

[Hung Bui]

Hi again,

NRF_ERROR_NO_MEM is not in the list of the return code from sd_ble_gap_auth_key_reply() which is the function that replyAuthKey() calls under the hood . So it must comes from the ble driver instead of the softdevice. 

You may want to debug into driver_gap.cpp to see get more info on which function giving NRF_ERROR_NO_MEM .