arbitrary assert with extended advertising

[PatH]

Hello fellow bit jugglers!

We are developing an application for a nRF52805 on a nRF52-DK board, using NCS.

NCS version: 1.5.1

Zephyr version: 2.4.99

BLE controller: Zephyr

IDE: SEGGER studio

OS: Windows 8

Our application generally seems to work, but there are spurious asserts after some time (sometimes after 30 seconds, sometimes after 10 minutes).

I reduced our application to the bare minimum MWE, as attached:

4075.MWE.zip

In this state, it is basically just trying to advertise forever, using extended advertising.

After letting the app run for some time, we inevitably land in an assert at this place:

WEST_TOPDIR/zephyr/subsys/bluetooth/controller/ll_sw/nordic/lll/lll_adv_aux.c:367

A screenshot of the error message:

I tried debugging the reason for the assert, but I'm not familiar enough with the BLE stack. It seems to assert that the radio is not ready at this point, for reasons that I don't know.

Please let me now if you need any more information from my side.

Thank you very much
Patrick

[Einar Thorsrud]

Hi Patrick,

I am not able to explain this at the moment but I will try to get some input.

By the way, may I ask why you are using the Zephyr LL instead of the SoftDevice Controller?

Einar

[PatH]

Hi Einar

Thanks for the quick reply!

We mainly use the zephyr controller because we're low on RAM on the nRF52805.

With CONFIG_BT_LL_SW_SPLIT=y, our RAM usage is 85.61%, and with CONFIG_BT_LL_SW_SPLIT=n, it is 108.22%

(which of course won't build).

Maybe there are some CONFIG_s I'm missing, that could reduce the RAM usage of the softdevice controller?

Kind regards

Patrick

[Einar Thorsrud]

Hi Patrick,

I see. The assert is catching ISR latency. Can you create a Zephyr GitHub issue and provide the details there?

Extended advertising is currently under very active development tin the Zephyr LL, so you should use the latest Zephyr upstream main branch if you want use it now. Also, note that advertising extensions is not qualified for the Zephyr LL yet, so you cannot use it in and end product before that has been done.

Einar

[PatH]

Hi Einar

We updated our NCS to version 1.6.0, and thus now use 2.6.0-rc1.

It seems that this fixes our problem. We let our application run for some hours, and no assert is triggered.

I'm not sure what the error was, and if it is now solved or only hidden, but I'll mark this as closed for now, ok?

Kind regards

Patrick