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,

Thank you for the information. I will relay this to our internal team. We will investigate this and get back to you.

Unfortunately, we are facing abnormally high loading, and it might take one or two weeks before we can follow up. Our apologies for the inconvenience.

Hieu

[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