Set TX Power Reporting Enable has no discernible effect

[bluetoothmdw]

I'm sending HCI command LE Set Transmit Power Reporting Enable with both local and remote reporting requested.

The Bluetooth Core Specification says "If the Remote_Enable parameter is set to 0x01 and no prior LE Power Control Request procedure has been initiated on the ACL connection, then the Controller shall initiate a new LE Power Control Request procedure (LL5.1.17) on that ACL".

The Power Control Request procedure says "The Link Layer initiates this procedure by sending an LL_POWER_CONTROL_REQ PDU".

But I see no power control PDUs exchanged.

Here's my code, which I call once after establishing the connection:

void set_tx_power_reporting_enable() {
	struct net_buf *rsp;
	struct net_buf *command;
	int err;

    uint8_t local_enable = 1;
    uint8_t remote_enable = 1;
	uint16_t conn_handle = 0;
    command = bt_hci_cmd_alloc(K_SECONDS(5));
	if (!command) {
		printk("set_tx_power_reporting_enable: No HCI command buffer!\n");
		return;
	}

	net_buf_add_le16(command, conn_handle);
	net_buf_add_u8(command, local_enable);
	net_buf_add_u8(command, remote_enable);

    err = bt_hci_cmd_send_sync(BT_HCI_OP_LE_SET_TX_POWER_REPORT_ENABLE, command, &rsp);
	if (err) {
		printk("set_tx_power_reporting_enable: HCI command failed (err %d)\n", err);
	} else {
		printk("set_tx_power_reporting_enable: HCI command OK\n");
	}
    net_buf_unref(rsp);
}

The command is working because I see this in the console:

set_tx_power_reporting_enable: HCI command OK

I see various control PDUs exchanged including feature request/response pairs and the features reported as being supported include Power Control Request and Path Loss Monitoring.

But no LL_POWER_CONTROL_REQ or LL_POWER_CONTROL_RSP.

I'm testing on a pair of nRD54L15-DK boards. AFAIK power control is supported.... at least the controller is reporting this to be the case.

Hope someone can share some wisdom on this.

Thank you in anticipation.

[Hung Bui]

Hi Martin, 

Could you try to call the host API  for the same function: https://docs.zephyrproject.org/latest/doxygen/html/group__bt__conn.html#gaa1f38911acee0534a8a6e414018c6fb6

One of our developers tried that and it worked for him: 

If it doesn't work please send us the full trace. If it does and you still prefer to call the HCI command directly we will need to check what caused that. 

Which SDK version you are using ? 

Btw, I learned a lot about PAwR from your SIG video, thanks for that, great one ;) 

[bluetoothmdw]

I didn't find that API! Ooops. That's why I was using HCI instead. I'll try it and report back.

My secret identity here is not so secret :-)  Glad you liked the video, it's great to hear that it helped.

I'm working with SDK v3.1.1 btw.

[bluetoothmdw]

Hey, it worked! Thank you so much :-)