Using the new Connection State module to decide role

[Chris]

I'm developing an application supporting concurrent central and peripheral connections and using the new Connection State module in SDK 10 to decide whether a BLE stack event should be handled by the central or peripheral event handler.

My ble_evt_dispatch() function is based closely on the Nordic ble_app_hrs_rscs_relay example, i.e.:

static void ble_evt_dispatch(ble_evt_t *p_ble_evt)
{
    uint16_t conn_handle;
    uint16_t role;

    ble_conn_state_on_ble_evt(p_ble_evt);   // Must be called before any event handler that uses conn state module

    // The connection handle should really be retrievable for any event type.
    conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
    role = ble_conn_state_role(conn_handle);

    if (role == BLE_GAP_ROLE_PERIPH)
    {   
        on_ble_peripheral_evt();
        ...
    }
    else if (role == BLE_GAP_ROLE_CENTRAL)
    {
        on_ble_central_evt();
        ...
    }
}

This worked fine until I had a scan timeout and discovered that the BLE_GAP_EVT_TIMEOUT handler in my on_ble_central_evt() was not getting called. On investigation I found that ble_conn_state_role() is returning BLE_GAP_ROLE_INVALID on a scan timeout because there is no connection so conn_handle is not set.

The ble_app_hrs_rscs_relay example has a BLE_GAP_EVT_TIMEOUT case in its on_ble_central_evt() function, but I wonder if this can ever get called. Shouldn't the ble_evt_dispatch() function include an explicit check for role == BLE_GAP_ROLE_INVALID in which it call functions to handle connectionless events such as BLE_GAP_EVT_TIMEOUT, or have I misunderstood how to use the ble_conn_state_role() function?

[Chris]

I'm not sure if this is the "best" answer but I've added the following to the end of my ble_evt_dispatch function:

...
else if (p_ble_evt->header.evt_id == BLE_GAP_EVT_TIMEOUT)
{  
    ble_advertising_on_ble_evt(p_ble_evt);
    on_ble_central_evt(p_ble_evt);
    on_ble_peripheral_evt(p_ble_evt);
}

The advertising, central and peripheral event handlers can then decide who should handle the timeout based on the value of p_gap_evt->params.timeout.src

[run_ar]

I think it's either this or add one more || to BLE_GAP_ROLE_CENTRAL like this:
else if ((role == BLE_GAP_ROLE_CENTRAL)
|| (p_ble_evt->header.evt_id == BLE_GAP_EVT_ADV_REPORT
|| (p_ble_evt->header.evt_id == BLE_GAP_EVT_TIMEOUT))