problems with usb virtual com port stm32f769 discovery

Question

I am trying to initialise VCP through usb on n stm32f769 diso.

The following function seems happy enough. But nothing happens. ioreg -p IOUSB doesn't detect anything

Where do I look next?

I am using vscode, platformio, stm hal, all on a mac m2 pro

uint8_t MX_USB_DEVICE_Init(void)
{

   /\* USER CODE BEGIN USB_DEVICE_Init_PreTreatment */
   /* USER CODE END USB_DEVICE_Init_PreTreatment */
   /* Init Device Library, add supported class and start the library. */
    if (USBD_Init(&USBD_Device, &VCP_Desc, 0) != USBD_OK)
    {
        return 0;
    }
    if (USBD_RegisterClass(&USBD_Device, USBD_CDC_CLASS) != USBD_OK)
    {
        return 0;
    }
    if (USBD_CDC_RegisterInterface(&USBD_Device, &USBD_CDC_fops) != USBD_OK)
    {
        return 0;
    }
    if (USBD_Start(&USBD_Device) != USBD_OK)
    {
        return 0;
    }
    /* USER CODE BEGIN USB_DEVICE_Init_PostTreatment */
    return 1;
    /* USER CODE END USB_DEVICE_Init_PostTreatment \*/
}

I was expecting ioreg -p IOUSB to display the usb cdc device. It only shows the st-link peripheral