ncs 3.0.2: concurrent scan and advertizing does not work anymore

[Yaxit]

Hello, as from title, after updating from ncs 2.7.0 to 3.0.2 my application cannot advertise and scan concurrently anymore.

If I start advertising after starting a scan:

[00:00:18.599,731] <inf> ble: Scanning started
[00:00:18.600,494] <wrn> bt_hci_core: opcode 0x2005 status 0x0c 
[00:00:18.600,830] <wrn> bt_id: cmd disallowed
[00:00:18.606,109] <err> main: Failed to start advertising, err -13

If I start scanning after starting advertising

[00:00:04.347,869] <wrn> bt_hci_core: opcode 0x200c status 0x12 
[00:00:04.348,236] <err> main: Failed to start scanning for peer, err -22

Advertising is started like this

int ble_adv_start(void){
    // with BT_LE_ADV_OPT_CONNECTABLE the advertizing stops automatically
    // when CONFIG_BT_MAX_CONN connections are established
    struct bt_data ad[] = {
        BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
        BT_DATA_BYTES(BT_DATA_NAME_SHORTENED, CONFIG_BT_DEVICE_NAME),
    };
    return bt_le_adv_start(
        BT_LE_ADV_PARAM(BT_LE_ADV_OPT_CONNECTABLE,
            BT_GAP_ADV_FAST_INT_MAX_1,
            BT_GAP_ADV_FAST_INT_MAX_2,
            NULL),  // todo: directed adv over disconnect?
        ad, ARRAY_SIZE(ad), NULL, 0);
}

Scanning is started like this

int ble_scan_for_peer(void){
    if(connections[BLE_CONN_PEER]){
        return -EALREADY;
    }
	/* Use active scanning and disable duplicate filtering to handle any
	 * devices that might update their advertising data at runtime. */
	struct bt_le_scan_param scan_param = {
		.type       = BT_LE_SCAN_TYPE_PASSIVE,
		.options    = BT_LE_SCAN_OPT_NONE,  // todo add coded phy support?
		.interval   = BT_GAP_PER_ADV_FAST_INT_MAX_2,
		.window     = BT_GAP_PER_ADV_FAST_INT_MIN_1,
	};

	int err = bt_le_scan_start(&scan_param, device_found);
	if(err){
        return err;
	}

    LOG_INF("Scanning started");

    return 0;
}

I'm also getting this warning warning: 'BT_LE_ADV_OPT_CONNECTABLE' is deprecated in the advertising function, but I think this should still work fine by reading the documentation.

This was working perfectly fine in 2.7.0. Was this feature deprecated? 

[Susheel Nuguru]

This issue looks very much like the issue shown in this thread. Can you try enabling CONFIG_BT_SCAN_WITH_IDENTITY=y in your prj.conf, pristine build and flash to see if it fixes the issue?

[Yaxit]

Sorry for the late reply, this worked. Not sure I understand fully the implications of scanning with identity, nor why it was possible in the previous NCS version (maybe different default?)

[Susheel Nuguru]

Glad that it worked Andrea.

The actual conflict came from the scanner and advertiser using the same controller address.I am not 100% sure but it seems what changed was the behavior in how the scanner and advertiser share the controller address.

[Yaxit]

I will close this ticket, but the solution seems more of a workaround than a solution, I think it should be possible to do both actions in a privacy-preserving way :)