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Commit c01b244a authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: add usbfs ioctl to retrieve the connection speed 



The usbfs interface does not provide any way for the user to learn the
speed at which a device is connected.  The current API includes a
USBDEVFS_CONNECTINFO ioctl, but all it provides is the device's
address and a one-bit value indicating whether the connection is low
speed.  That may have sufficed in the era of USB-1.1, but it isn't
good enough today.

This patch introduces a new ioctl, USBDEVFS_GET_SPEED, which returns a
numeric value indicating the speed of the connection: unknown, low,
full, high, wireless, super, or super-plus.

Similar information (not exactly the same) is available through sysfs,
but it seems reasonable to provide the actual value in usbfs.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Reported-by: default avatarReinhard Huck <reinhard.huck@thesycon.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 81606aea

drivers/usb/core/devio.c

+3 −0
Original line number Diff line number Diff line
@@ -2537,6 +2537,9 @@ static long usbdev_do_ioctl(struct file *file, unsigned int cmd, 
	case USBDEVFS_DROP_PRIVILEGES:

		ret = proc_drop_privileges(ps, p);

		break;

	case USBDEVFS_GET_SPEED:

		ret = ps->dev->speed;

		break;

	}



 done:

include/uapi/linux/usbdevice_fs.h

+6 −0
Original line number Diff line number Diff line
@@ -156,6 +156,11 @@ struct usbdevfs_streams { 
	unsigned char eps[0];

};



/*

 * USB_SPEED_* values returned by USBDEVFS_GET_SPEED are defined in

 * linux/usb/ch9.h

 */



#define USBDEVFS_CONTROL           _IOWR('U', 0, struct usbdevfs_ctrltransfer)

#define USBDEVFS_CONTROL32           _IOWR('U', 0, struct usbdevfs_ctrltransfer32)

#define USBDEVFS_BULK              _IOWR('U', 2, struct usbdevfs_bulktransfer)
@@ -190,5 +195,6 @@ struct usbdevfs_streams { 
#define USBDEVFS_ALLOC_STREAMS     _IOR('U', 28, struct usbdevfs_streams)

#define USBDEVFS_FREE_STREAMS      _IOR('U', 29, struct usbdevfs_streams)

#define USBDEVFS_DROP_PRIVILEGES   _IOW('U', 30, __u32)

#define USBDEVFS_GET_SPEED         _IO('U', 31)



#endif /* _UAPI_LINUX_USBDEVICE_FS_H */