USBX 10 second delay at initialisation.

[JimJW]

I am trying to use ThreadX/FileX/USBX to read/write files on a USB memory stick.
It appears to work but there is a 10 second delay between initialisation and File access.
I have tracked this down to:

Thread #1 [main] 1 [core: 1] (Suspended : Step)	
	_ux_host_class_storage_transport_bo() at ux_host_class_storage_transport_bo.c:282 0x8011378	
	_ux_host_class_storage_transport() at ux_host_class_storage_transport.c:98 0x8011262	
	_ux_host_class_storage_media_characteristics_get() at ux_host_class_storage_media_characteristics_get.c:126 0x8010d9c	
	_ux_host_class_storage_device_initialize() at ux_host_class_storage_device_initialize.c:134 0x8010964	
	_ux_host_class_storage_activate() at ux_host_class_storage_activate.c:191 0x80107b6	
	_ux_host_stack_configuration_interface_scan() at ux_host_stack_configuration_interface_scan.c:179 0x8012000	
	_ux_host_stack_class_interface_scan() at ux_host_stack_class_interface_scan.c:106 0x8011d70	
	_ux_host_stack_new_device_create() at ux_host_stack_new_device_create.c:282 0x80128a6	
	_ux_host_stack_rh_device_insertion() at ux_host_stack_rh_device_insertion.c:183 0x8012b80	
	_ux_host_stack_rh_change_process() at ux_host_stack_rh_change_process.c:156 0x8012aba	
	_ux_host_stack_enum_thread_entry() at ux_host_stack_enum_thread_entry.c:116 0x8012496	
	_tx_thread_shell_entry() at tx_thread_shell_entry.c:114 0x800ee1c	
	<signal handler called>() at 0xffffffff	

 This function calls
    _ux_host_stack_transfer_request(transfer_request);
then waits for semaphore ux_transfer_request_semaphore with a 10 second timeout.
The wait does timeout so we climb out of the stack of calls, and get on with reading and writing files which seem to be OK.

The problem calls seems to stem from a call a few steps down the stack in _ux_host_class_storage_device_initialize(), which has:

        /* Get the media type supported by this storage device.  */
        status =  _ux_host_class_storage_media_characteristics_get(storage);
        if (status == UX_HOST_CLASS_MEDIA_NOT_SUPPORTED)
        {
            ...
        }
        if (status != UX_SUCCESS)
            return(status);

It looks as if the semaphore should be signalled in:
void HAL_HCD_HC_NotifyURBChange_Callback(HCD_HandleTypeDef *hhcd, uint8_t chnum, HCD_URBStateTypeDef urb_state)
which is called from the ISR. This works for all the other calls, but in this case, urb_state is always URB_NOTREADY so we never reach:

    /* Wake up the transfer request thread.  */
    _ux_host_semaphore_put(&transfer_request -> ux_transfer_request_semaphore);

I could just reduce the timeout but that doesn't really seem like the right solution!

Any thoughts would be appreciated.

CubeMX Version 6.17.0
STM32H573