USB_DT_MS_ENDPOINT_SIZE
ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
USB_DT_MS_ENDPOINT_SIZE(midi2->num_midi1_out);
USB_DT_MS_ENDPOINT_SIZE(midi2->num_midi1_in);