USB: add usbfs ioctl to retrieve the connection speed (c01b244a) · Commits · 戴 / test

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:

Alan Stern <stern@rowland.harvard.edu> Reported-by:

Reinhard Huck <reinhard.huck@thesycon.de> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 */

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