Enable multipe slaves in NCS nrf_desktop keyboard

Question

Hi guys,

I want to add the function of multiple slaves to the nrf_desktop routine to support two hosts to connect to the keyboard.This routine is in the ncs1.4.1\v1.4.1\nrf\applications\nrf_desktop directory. So I added a macro definition ( CONFIG_BT_MAX_CONN 2) in app_ZDebug.conf file.

But I encoutered the following compilation problem:

1.

BUILD_ASSERT(!IS_ENABLED(CONFIG_BT_PERIPHERAL) ||
		     (ARRAY_SIZE(active_conn) == 1));

in ble_state.c line 398.

After I blocked the code，my keyboard supports simultaneous connection of two devices.but I encoutered a new problem which occurred when the second device was bound. The error log is as follows:

2.

[01779879] <inf> ble_state: Connected to 48:01:c5:21:6c:9a (public)
[01779887] <inf> event_manager: e: ble_peer_event id=0x20002e38 CONNECTED 
[01779888] <wrn> bt_conn_ctx: Memory can not be allocated                        
[01779889] <wrn> bt_hids: There is no free memory to allocate the connection context  
[01779889] <err> hids: Failed to notify the HID Service about the connection           

ASSERTION FAIL [cur_conn == ((void *)0)] @ ../src/modules/hids.c:473

I try to modify the heap size (CONFIG_HEAP_MEM_POOL_SIZE) in app_ZDebug.conf file.but still can not solve the problem.

How to bind the keyboard to two host devices at the same time?

Carl Richard · Accepted Answer

Hi!

Could you try adding CONFIG_BT_HIDS_MAX_CLIENT_COUNT=2 to the app_ZDebug.conf file aswell? This enables the conn_ctx to account for one more connection.

I would also like to add that this functionality, as you may have understood, isn't really supported by nrf_desktop so you may face other issues later on.

Best regards,
Carl Richard

Carl Richard · Answer

My pleasure! Have a good day. Best regards, Carl Richard

Enable multipe slaves in NCS nrf_desktop keyboard

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