HFP AG example: outgoing callback not triggered (IDFGH-2931)

[pavestru]

Environment

• Development Kit: ESP32-Wrover-Kit
• Kit version v4
• Module or chip used: ESP32-WROVER-B
• IDF version: v4.2-dev-781-g47253a827
• Build System: make
• Compiler version: xtensa-esp32-elf-gcc (crosstool-NG esp-2019r2) 8.2.0
• Operating System: macOS
• Using an IDE?: No
• Power Supply: USB

Problem Description

ESP32 connects to a BT headset, receives audio from BT headset (CVSD codec), however, it is not sending audio to the same BT headset. Callback bt_app_hf_outgoing_cb (see here) almost never gets called. If it ever does, it is followed by a crash exactly like described in #4794 .

Expected Behavior

Callback bt_app_hf_outgoing_cb is expected to get called to play the sine wave in the headphones.

Actual Behavior

Callback bt_app_hf_outgoing_cb is not run at all except very rarely and randomly, followed by crashes exactly like described in #4794 .

Steps to reproduce

1. Open [HFP AG](https://github.com/espressif/esp-idf/tree/master/examples/bluetooth/bluedroid/classic_bt/hfp_ag example)
2. put a ESP_LOGI("..."); statement to both bt_app_hf_outgoing_cb and bt_app_hf_incoming_cb
3. Follow README in hfp_ag example
4. Uncomment this line and put mac address of your BT headset there
5. Set HCI data path in menuconfig
6. leave Bluedroid Options --> Wide Band Speech off
7. set BR/EDR Sync(SCO/eSCO) Max Connections to 1 or more (default is 0)
8. make flash monitor (runs HFP AG example)
9. hf con; (if not connected yet)
10. hf cona;

Code to reproduce this issue

Example code for callbacks in bt_app_hf.c:

static uint32_t bt_app_hf_outgoing_cb(uint8_t *p_buf, uint32_t sz)
{
    ESP_LOGE(BT_HF_TAG, "bt_app_hf_outgoing_cb");
    
    int sine_phase = esp_random();

    for (int i = 0; i < TABLE_SIZE_CVSD; i++) {
        p_buf[i * 2]     = sine_int16[sine_phase];
        p_buf[i * 2 + 1] = sine_int16[sine_phase];
        ++sine_phase;
        if (sine_phase >= TABLE_SIZE_CVSD) {
            sine_phase -= TABLE_SIZE_CVSD;
        }
    }
    return sz;
}
 
static void bt_app_hf_incoming_cb(const uint8_t *buf, uint32_t sz)
{
    ESP_LOGE(BT_HF_TAG, "bt_app_hf_incoming_cb, buf size: %d", sz);
    // direct to i2s
    esp_hf_outgoing_data_ready();
}

Note

I am using Sony SBH20 and Sony WH-1000XM3 headsets, both have the same behaviour.

Thank you.

[Alvin1Zhang]

@pavestru Thanks for reporting, we will look into.

[KollarRichard]

Hi, is there any news on this issue?

[ypiotrp]

Hi. I got the same issue on the newest master. What is the status here? Is it a work in progress?

[howroyd]

Same issue here. The outgoing callback hasn't been called once, but the incoming is firing as expected.

[howroyd]

Just tested on latest pull from release v4.2 and still got the issue.

My log is just being flooded with the following. Incoming audio (from HFP client) seems ok, but a little glitchy. Certainly nowhere near as stable as A2DP.

W (22802) BT_APPL: bta_ag_sco_read_cback: status(2)

From what I can see this is a warning that there is no data in the SCO layer? Not surprising since the callback isn't being called to retrieve the data.

[glennhuber]

Just tested on 4.3 and still not working. Is this issue being looked into at Espressif?

[ypiotrp]

Hi @Alvin1Zhang! Have made any progress on this issue?

[Alvin1Zhang]

Thanks for the updates, and sorry for slow turnaround, we are still debugging this issue, will share updates once available. Thanks.

[boblane1]

Hi, @pavestru and other users!
I offer a patch to fix this problem, you can have a try. Please let me know if it still has problems. By the way, it is not recommended to print too much information in the callback function.

0001-fix-ag-example-outgoing-callback-not-triggered.zip

[ypiotrp]

Hi @boblane1!
I applied the patch you shared to release v4.1 ESP-IDF and this is the result that I got - https://www.youtube.com/watch?v=peONupbGCGs. I don't know if this is what should be expected but it is definitely a step up.

Thank you very much!

For everyone else. To reproduce this effect checkout the ESP-IDF at v4.1, apply the patch from the @boblane1's post, change the SCO path to HCI, disable the Wide Band Speech and change the BR/EDR Sync(SCO/eSCO) Max Connections to 1. Compile, flash, voila!