Failed to star advertising after dissconnect error -12

Question

Hi im having problems with restarting advertising after disconnect. I tried NUS example, simple peripheral example but none of them works.

I modified NUS example with some extra functions but i cannot get it to work.
Unreferencing current connection as advised on forum doesnt help either.

/*
 * Copyright (c) 2024 Croxel, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/kernel.h>
#include <zephyr/bluetooth/bluetooth.h>
#include <zephyr/bluetooth/services/nus.h>

#define DEVICE_NAME		"XX45"
#define DEVICE_NAME_LEN		(sizeof(DEVICE_NAME) - 1)

static struct bt_conn *current_conn;

static const struct bt_data ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
	BT_DATA(BT_DATA_NAME_COMPLETE, DEVICE_NAME, DEVICE_NAME_LEN),
};

static const struct bt_data sd[] = {
	BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_SRV_VAL),
};

static void notif_enabled(bool enabled, void *ctx)
{
	ARG_UNUSED(ctx);

	printk("%s() - %s\n", __func__, (enabled ? "Enabled" : "Disabled"));
}

static void received(struct bt_conn *conn, const void *data, uint16_t len, void *ctx)
{
	char message[CONFIG_BT_L2CAP_TX_MTU + 1] = "";

	ARG_UNUSED(conn);
	ARG_UNUSED(ctx);

	memcpy(message, data, MIN(sizeof(message) - 1, len));
	printk("%s() - Len: %d, Message: %s\n", __func__, len, message);
}

struct bt_nus_cb nus_listener = {
	.notif_enabled = notif_enabled,
	.received = received,
};

int advertising_start()
{
	int err;
		err = bt_le_adv_start(BT_LE_ADV_CONN_ONE_TIME, ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));

	if (err) {
		printk("Failed to start advertising: %d\n", err);
		return err;
	}
return 0;
}


static void connected(struct bt_conn *conn, uint8_t err)
{
	char addr[BT_ADDR_LE_STR_LEN];

	if (err) {
		printk("Connection failed, err 0x%02x", err);
		return;
	}

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
	printk("Connected %s", addr);

	current_conn = bt_conn_ref(conn);

	//dk_set_led_on(CON_STATUS_LED);
}

static void disconnected(struct bt_conn *conn, uint8_t reason)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	printk("Disconnected: %s, reason 0x%02x ", addr, reason );

	if (current_conn) {
		bt_conn_unref(current_conn);
		current_conn = NULL;
		//dk_set_led_off(CON_STATUS_LED);
		printk("Dereferenced current_conn\n");
		advertising_start();
	}
}

BT_CONN_CB_DEFINE(conn_callbacks) = {
	.connected    = connected,
	.disconnected = disconnected,
};

int main(void)
{
	int err;

	printk("Sample - Bluetooth Peripheral NUS\n");

	err = bt_nus_cb_register(&nus_listener, NULL);
	if (err) {
		printk("Failed to register NUS callback: %d\n", err);
		return err;
	}

	err = bt_enable(NULL);
	if (err) {
		printk("Failed to enable bluetooth: %d\n", err);
		return err;
	}

	advertising_start();

	printk("Initialization complete\n");

	while (true) {
		const char *hello_world = "Hello World!\n";

		k_sleep(K_SECONDS(3));

		err = bt_nus_send(NULL, hello_world, strlen(hello_world));
		printk("Data send - Result: %d\n", err);

		if (err < 0 && (err != -EAGAIN) && (err != -ENOTCONN)) {
			return err;
		}
	}

	return 0;
}

Data send - Result: -128
Connected 5B:4F:15:AE:C7:0B (random)Data send - Result: -128
notif_enabled() - Enabled
notif_enabled() - Disabled
Data send - Result: -128
Disconnected: 5B:4F:15:AE:C7:0B (random), reason 0x13 Dereferenced current_conn
Failed to start advertising: -12

mojangeex · Accepted Answer

this example is working as expected. I build it on my machine and device starts advertising after disconnect normally. 
 Other example zephyr\samples\bluetooth\peripheral_nus that I used before seems to have some issues. 
 Thanks for the help.

Failed to star advertising after dissconnect error -12

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