Can't use bt_enable when I use sysbuild and enabled IPC_RADIO

[ashun]

Hi, Team.

We are currently using NCS v2.7.0 with the sysbuild approach on the nRF5340. We referred to the nrf/sample/matter/lock code and copied its sysbuild configuration (as we need Matter support in the future).

However, we encountered an issue:

• When enabling the network core IPC_RADIO, the bt_enable function in my code fails to execute properly. The underlying hci_core returns -11 (EAGAIN or resource unavailable).

• When I disable IPC_RADIO and instead only use SB_CONFIG_NETCORE_HCI_IPC=y, the Bluetooth functionality works correctly.

Question:
1 - Did I miss any configuration steps to enable IPC_RADIO and  use bt_enable() work properly?

2 - Both Bluetooth and IEEE 802.15.4 are supported, so why does the Matter sample code use IPC_RADIO for the network core instead of Multiprotocol_RPMsg?
     Is there any particular reason for this?

[Charlie]

Hi,

BLE and Thread both rely on the same IPC radio controlled by the netcore. Because of this shared resource, it is not feasible to run a BLE application alongside a Matter/Thread application simultaneously.

In the lock sample, BLE is only utilized for commissioning purposes before the Matter application actually starts running.

Best regards,

Charlie

[ashun]

Got it.

BLE and Thread should have a switching interface, is there any relevant documentation or sample code reference?

The Bluetooth of the network core IPC radio and the Bluetooth of the application core should also be different, right?