Bluetooth: Set LE Suggested Default Data Length to maximum

When LE Data Packet Length Extension is supported, then actually
increase the suggested default data length to the maximum to enable
higher througput.

< HCI Command: LE Read Maximum Data Length (0x08|0x002f) plen 0
> HCI Event: Command Complete (0x0e) plen 12
      LE Read Maximum Data Length (0x08|0x002f) ncmd 1
        Status: Success (0x00)
        Max TX octets: 251
        Max TX time: 2120
        Max RX octets: 251
        Max RX time: 2120

< HCI Command: LE Read Suggested Default Data Length (0x08|0x0023) plen 0
> HCI Event: Command Complete (0x0e) plen 8
      LE Read Suggested Default Data Length (0x08|0x0023) ncmd 1
        Status: Success (0x00)
        TX octets: 27
        TX time: 328

< HCI Command: LE Write Suggested Default Data Length (0x08|0x0024) plen 4
        TX octets: 251
        TX time: 2120
> HCI Event: Command Complete (0x0e) plen 4
      LE Write Suggested Default Data Length (0x08|0x0024) ncmd 1
        Status: Success (0x00)
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

net/bluetooth/hci_core.c

@@ -771,6 +771,15 @@ static int hci_init4_req(struct hci_request *req, unsigned long opt)
 			    sizeof(support), &support);
 	}
 
+	/* Set Suggested Default Data Length to maximum if supported */
+	if (hdev->le_features[0] & HCI_LE_DATA_LEN_EXT) {
+		struct hci_cp_le_write_def_data_len cp;
+
+		cp.tx_len = hdev->le_max_tx_len;
+		cp.tx_time = hdev->le_max_tx_time;
+		hci_req_add(req, HCI_OP_LE_WRITE_DEF_DATA_LEN, sizeof(cp), &cp);
+	}
+
 	return 0;
 }