10 second delay after PB-GATT completed until first Mesh Proxy Service advertisement

[JonasJ]

Hi,

After provisioning a device using PB-GATT there is a 10 second delay after the PB-GATT connection is closed and the first Mesh Proxy Service advertisement is sent.

When the PB-GATT connection is closed the stack will end up in sd_state_evt_handler in mesh_provisionee.c after both the mesh stack and softdevice has been disabled.

The code will go on and call proxy_node_id_enable() -> adv_start() -> mesh_adv_start() -> sd_ble_gap_adv_start() and timeslot_restart().

I suspect that the issue is with timeslot_restart() as it's configured to request maximum 10 second timeslots by default (TIMESLOT_MAX_LENGTH_US). If this value is changed to 7 seconds I see a 7 second delay instead.

This issue can be seen by provisioning a device with light_switch_server_nrf52832_xxAA_s132_6.1.0_merged.hex from SDK for Mesh v3.1.0 using the nRF Mesh iOS app.

Attach is a pcap file that shows this behavior. Compare the time between packet 155 and 156, there is a delay of 10 seconds.

From the Mesh Profile v1.0.1, section 7.2.2.2.3 "Advertising with Node Identity"

"If PB-GATT is supported and Mesh Proxy Service is exposed, immediately after provisioning is completed
using PB-GATT (see Section 5.2.2), the Mesh Proxy Service shall start advertising with Node Identity
using the provisioned network."

provision_light_switch_server.pcapng

Thanks.

[Bjørn Kvaale]

It seems this workaround was slightly unstable, as figured out internally & thanks to JonasJ in this case! We have a new workaround. In the bearer_handler.c file found under mesh/bearer/src/bearer_handler.c, you can make these changes inside the bearer_handler_stop() function:

--- a/mesh/bearer/src/bearer_handler.c
+++ b/mesh/bearer/src/bearer_handler.c
@@ -319,10 +319,14 @@ uint32_t bearer_handler_stop(bearer_handler_stopped_cb_t cb)
         /* Will stop the timeslot when the current action ends. */
         m_stopped_callback = cb;
         m_stopped = true;
-        if (timeslot_session_is_active())
+        if (timeslot_is_in_ts())
         {
             timeslot_trigger();
         }
+        else if (timeslot_session_is_active())
+        {
+            timeslot_stop();
+        }
         else
         {
             notify_stop();

Update: As can be seen in this case, one should also replace action_switch() in bearer_handler_timer_irq_handler() with this code:

 if (m_stopped)
        {
            timeslot_stop();
        }
        else
        {
            action_switch();
        }

This ensures that the 10 second delay works in both PB-ADV & PB-GATT. Without this extra code, the 10 second delay is still present in PB-ADV.

[JonasJ]

Thanks, this worked as expected.