Latest Intel driver connection issue

[piseek]

We're using nRF Connect with SDK v2.4.0 (Zephyr). 
Central and peripheral roles combined.

Custom hardware, with Fanstels module BT840

All was working well, but after extensive testing, we encountered a problem connecting our hardware to the certain integrated BLE Intel chipset on some of the Laptops.
The connection gets rejected, it looks like some security issue.
We tried different sets of drivers and it looks like only new drivers have this issue.

• We cannot connect if the Intel driver version is 22.250.0 or newer.
• We can connect with a laptop if the Intel driver version is 22.240.0 or less.

We tried to downgrade the driver on affected laptops and then we were able to establish a Bluetooth connection.

Intel driver list and corresponding release notes can be found here:
https://www.intel.com/content/www/us/en/download/18649/787935/intel-wireless-bluetooth-for-windows-10-and-windows-11.html

We are about to release the product, but first, we need to solve this issue, any advice will be much appreciated.

Best Regards
Andrej

[Vidar Berg]

Hi Andrej,

Thanks for providing the logs. It shows that the link is terminated due to timeout. Can you capture a sniffer trace of the failing connections with the nRF Sniffer for Bluetooth LE? I have not found any other reports of this problem, have you?

Also, advertising is restarted automatically upon disconnect, but it appears that you are also trying to start if from your application. 

Best regards,

Vidar

[piseek]

Hi Vidar,

Here is the output of Wireshark.

not working export wireshark.txt

We've tried your example "Zephyr Peripheral Sample Long Name" on nRF52840DK board and were also unable to establish the connection. 

With other BLE devices (loudspeakers, headsets,...), we had no trouble.

Regards,
Andrej

[Vidar Berg]

Hi Andrej,

Please upload the *.pcapng file for your capture. I'm unable to open the file you uploaded in WS. 

piseek said:

With other BLE devices (loudspeakers, headsets,...), we had no trouble.

 Are you sure these are BLE devices, not Bluetooth classic?

[piseek]

4578.capture.pcapng

Regards,
Andrej

[Vidar Berg]

Hi Andrej,

There were multiple connections in your trace that succeeded, and one that failed. Please try to not initiate the MTU request from your peripheral and see if you experience the same.

Vidar Berg said:

 Are you sure these are BLE devices, not Bluetooth classic?