HCI Error(0x2A) in hci_pwr_ctrl example on nRF52840DK

[Robin]

Hello Nordic Team,

HW: nRF52840DK

SDK: ncs v2.8.0

App: hci_pwr_ctrl

I am testing with hci_pwr_ctrl example to see how tx power can be set from application.

The example application works fine during advertising. However when I tried to connect it from nRF Connect app on Galaxy S20,  the example application gets disconnected with reason 0x2A right after it is connected. seeing the reason in string format, it appears as BT_HCI_ERR_DIFF_TRANS_COLLISION.

Q1) What does the error mean?

Q2) How can I avoid the error?

Thanks your support in advance,

Robin

[Hung Bui]

Hi Robin, 

Do you have the same problem when testing with other sample ? 

Are you using the Zephyr controller (CONFIG_BT_LL_SW_SPLIT=y)or our Softdevice Controller ? 

Error BT_HCI_ERR_DIFF_TRANS_COLLISION happen when one transaction (request + response) is on going but one of the device send another request when the previous request has not finished yet. 

A sniffer trace would be useful to see if it's actually the case. 

[Robin]

Hi Hung,

I didn't make any modification on the example. It is off-the-shelf example application. Seeing final .config file in hci_pwr_ctrl\build\hci_pwr_ctrl\zephyr\.config file, it apears like this: # CONFIG_BT_LL_SW_SPLIT is not set.

Can you please try it in your end and see if the problem is reproduced with off-the-shelf example?

Thanks,

Robin

[Hung Bui]

Hi Robin, 

I did try to test with the default sample and my galaxy S22 and got no problem.
The challenge is that we may need to have the same phone to be able to reproduce the issue. That's why a sniffer a trace is needed. I suspect that the issue was with the phone that it try to send multiple requests at the same time. 

[Robin]

Hi Hung,

Thanks for the update. Let me try it on Galaxy S22. I'll report again soon.

Thanks