USB_GET_DEVICE_DESCRIPTOR

Section: (9)
Updated: 17 July 2003
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NAME

usb_get_device_descriptor - (re)reads the device descriptor  

SYNOPSIS

int usb_get_device_descriptor (struct usb_device * dev);  

ARGUMENTS

dev
the device whose device descriptor is being updated
 

CONTEXT

!in_interrupt ()  

DESCRIPTION

Updates the copy of the device descriptor stored in the device structure, which dedicates space for this purpose. Note that several fields are converted to the host CPU's byte order: the USB version (bcdUSB), and vendors product and version fields (idVendor, idProduct, and bcdDevice). That lets device drivers compare against non-byteswapped constants.

There's normally no need to use this call, although some devices will change their descriptors after events like updating firmware.

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.  

ABOUT THIS DOCUMENT

This documentation is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

For more details see the file COPYING in the source distribution of Linux.

If you have comments on the formatting of this manpage, then please contact Michael Still (mikal@stillhq.com).

This documentation was generated with kernel version 2.5.71.


 

Index

NAME
SYNOPSIS
ARGUMENTS
CONTEXT
DESCRIPTION
ABOUT THIS DOCUMENT

This document was created by man2html, using the manual pages.
Time: 02:18:38 GMT, July 17, 2003