Provided by: linux-doc-2.6.15_2.6.15-23.39_all bug


       usb_get_descriptor - issues a generic GET_DESCRIPTOR request


       int usb_get_descriptor  (struct usb_device * dev, unsigned char type,
                                 unsigned char index, void * buf, int size);


       dev    the device whose descriptor is being retrieved

       type   the descriptor type (USB_DT_*)

       index  the number of the descriptor

       buf    where to put the descriptor

       size   how big is ‘‘buf’’?


       !in_interrupt ()


       Gets a USB descriptor. Convenience functions exist to simplify  getting
       some  types  of  descriptors.  Use  usb_get_string  or  usb_string  for
       USB_DT_STRING. Device  (USB_DT_DEVICE)  and  configuration  descriptors
       (USB_DT_CONFIG)  are  part  of  the  device structure. In addition to a
       number   of   USB-standard   descriptors,   some   devices   also   use
       class-specific or vendor-specific descriptors.

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

       Returns the number of bytes received on success,  or  else  the  status
       code returned by the underlying usb_control_msg call.