Man page 9 : usb_string

usb_string - returns UTF-8 version of a string descriptor

int usb_string(struct usb_device *  dev , int  index , char *  buf , size_t  size );

dev
    the device whose string descriptor is being retrieved

index
    the number of the descriptor

buf
    where to put the string

size
    how big is « buf »?

!in_interrupt ()

This converts the UTF-16LE encoded strings returned by devices, from usb_get_string_descriptor, to null-terminated UTF-8 encoded ones that are more usable in most kernel contexts. Note that this function chooses strings in the first language supported by the device.

This call is synchronous, and may not be used in an interrupt context.

Returns length of the string (>= 0) or usb_control_msg status (< 0).