Man page 9 : usb_string_id

usb_string_id - allocate an unused string ID

int usb_string_id(struct usb_composite_dev *  cdev );

cdev
    the device whose string descriptor IDs are being allocated

single threaded during gadget setup

usb_string_id() is called from bind callbacks to allocate string IDs. Drivers for functions, configurations, or gadgets will then store that ID in the appropriate descriptors and string table.

All string identifier should be allocated using this, usb_string_ids_tab() or usb_string_ids_n() routine, to ensure that for example different functions donAqt wrongly assign different meanings to the same identifier.

David Brownell <>
    Author.