[TW#25603] Bluetooth visibility in dual mode

[crespum]

Environment

• IDF version: I've tried both 53509c7 (v3.1-rc) and latest v3.0.3
• Development Env: Make
• Operating System: Fedora
• Power Supply: USB

Problem Description

My application uses Bluetooth dual mode, to be precise it uses A2DP and a BLE beacon, but I'm experiencing some issues with the visibility of the different modes:

I want the beacon to be always visible but not the A2DP profile. The latter should only be visible for an small amount of time. The A2DP profile should remain connectable for the devices which have already been bond.

To achieve this I've tried the function esp_bt_gap_set_scan_mode, which according to the docs should "set discoverability and connectability mode for legacy bluetooth". However, after calling esp_bt_gap_set_scan_mode(ESP_BT_SCAN_MODE_CONNECTABLE), the BLE advertisement completely disappears.

Why does esp_bt_gap_set_scan_mode affect the BLE stack?

Code to reproduce this issue

To test the issue you can apply the following patch to a2dp_gatts_coex example. The advertisement should be visible the first 30 seconds and disappear right after the logs print Beacon disappears now.

102c102
<     .own_addr_type      = BLE_ADDR_TYPE_PUBLIC,
---
>     .own_addr_type      = BLE_ADDR_TYPE_RANDOM,
258a259
>         esp_ble_gap_config_local_privacy(true);
380,381c381,382
<         // esp_ble_conn_update_params_t conn_params = {0};
<         // memcpy(conn_params.bda, param->connect.remote_bda, sizeof(esp_bd_addr_t));
---
>         esp_ble_conn_update_params_t conn_params = {0};
>         memcpy(conn_params.bda, param->connect.remote_bda, sizeof(esp_bd_addr_t));
623c624
<         esp_bt_gap_set_scan_mode(ESP_BT_SCAN_MODE_NONE);
---
>         esp_bt_gap_set_scan_mode(ESP_BT_SCAN_MODE_CONNECTABLE_DISCOVERABLE);
705,708d705
< 
<     vTaskDelay(30000 / portTICK_PERIOD_MS);
<     ESP_LOGI(BT_BLE_COEX_TAG, "Beacon disappears now");
<     esp_bt_gap_set_scan_mode(ESP_BT_SCAN_MODE_CONNECTABLE_DISCOVERABLE);

[TianHao-Yoursmake]

@crespum, thank you. It's real a problem. It's due to that when call esp_bt_gap_set_scan_mode(ESP_BT_SCAN_MODE_CONNECTABLE_DISCOVERABLE), it will also set hci cmd to disable advertising.

We will fix it soon.

[Alvin1Zhang]

@crespum Have you verified the fix patch? Does the patch resolve your issue? Thanks.

[crespum]

No, I'm still experiencing the issue on v3.1.

[crespum]

This issue has been fixed in v3.1.1. Thanks @igrr!