BT connection timeouts with PAWR enabled

[saty9pd]

sdk-nrf: v2.7.0

When PAWR is enabled I no longer get connection timeouts as a callback to bt_conn_cb.connected with the conn_err parameter set when attempting to open a connection as a central.

Instead I get an error log from inside bt_hci_core.

Code to start connection
```

struct bt_conn_le_create_param con_params = BT_CONN_LE_CREATE_PARAM_INIT(BT_CONN_LE_OPT_NONE, BT_GAP_SCAN_FAST_INTERVAL, BT_GAP_SCAN_FAST_INTERVAL);
con_params.timeout = 500;

err = bt_conn_le_create(&target_address, &con_params, BT_LE_CONN_PARAM_DEFAULT, &conn);
```

Logs I get

```

00> rtt:~$ [0:0:5.943,420] <dbg> EDGE_HEARTBEAT_PERIPHERAL: connect_to_peripheral: attempted connection start

00> rtt:~$ rtt:~$ [0:0:10.943,298] <err> bt_hci_core: Invalid connection complete event

```

I have validated this is from PAWR by disabling it and confirming I do get the expected callback.

Flags enabled when we use PAWR

select BT_OBSERVER

select BT_EXT_ADV
select BT_CTLR_ADV_EXT

select BT_PER_ADV_SYNC
select BT_PER_ADV_SYNC_RSP
select BT_PER_ADV_SYNC_TRANSFER_SENDER
select BT_PER_ADV_SYNC_TRANSFER_RECEIVER

select BT_CTLR_SYNC_PERIODIC
select BT_CTLR_SYNC_PERIODIC_RSP

[Hieu]

Hi saty9pd,

I forgot to ask, for this and https://devzone.nordicsemi.com/f/nordic-q-a/112920/pawr-prevents-cancelling-a-pending-connection, what PAwR role is this central device in?

Hieu

[saty9pd]

Sorry if I am using the wrong terminology.

The central device (the one running the code I posted) is the one subscribing to the PAWR advertiser and sending responses back to it

[Hieu]

Could you please try this workaround?

Adding this line in hci_core.c after LOG_ERR("Invalid connection complete event");

enh_conn_complete((struct bt_hci_evt_le_enh_conn_complete *)evt);

The function le_enh_conn_complete_v2 should then look like this:

static void le_enh_conn_complete_v2(struct net_buf *buf)
{
 struct bt_hci_evt_le_enh_conn_complete_v2 *evt =
  (struct bt_hci_evt_le_enh_conn_complete_v2 *)buf->data;

 if (evt->adv_handle == BT_HCI_ADV_HANDLE_INVALID &&
     evt->sync_handle == BT_HCI_SYNC_HANDLE_INVALID) {
  /* The connection was not created via PAwR, handle the event like v1 */
  enh_conn_complete((struct bt_hci_evt_le_enh_conn_complete *)evt);
 }
#if defined(CONFIG_BT_PER_ADV_RSP)
 else if (evt->adv_handle != BT_HCI_ADV_HANDLE_INVALID &&
   evt->sync_handle == BT_HCI_SYNC_HANDLE_INVALID) {
  /* The connection was created via PAwR advertiser, it can be handled like v1 */
  enh_conn_complete((struct bt_hci_evt_le_enh_conn_complete *)evt);
 }
#endif /* CONFIG_BT_PER_ADV_RSP */
#if defined(CONFIG_BT_PER_ADV_SYNC_RSP)
 else if (evt->adv_handle == BT_HCI_ADV_HANDLE_INVALID &&
   evt->sync_handle != BT_HCI_SYNC_HANDLE_INVALID) {
  /* Created via PAwR sync, no adv set terminated event, needs separate handling */
  struct bt_le_per_adv_sync *sync;

  sync = bt_hci_get_per_adv_sync(evt->sync_handle);
  if (!sync) {
   LOG_ERR("Unknown sync handle %d", evt->sync_handle);

   return;
  }

  bt_hci_le_enh_conn_complete_sync(evt, sync);
 }
#endif /* CONFIG_BT_PER_ADV_SYNC_RSP */
 else {
  LOG_ERR("Invalid connection complete event");
  enh_conn_complete((struct bt_hci_evt_le_enh_conn_complete *)evt);
 }
}

[saty9pd]

That seems to work i now get a callback to my connection handler on timeout. Once the device it was trying to connect to became available it succeeded the next time bt_conn_le_create was called