diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2017-06-05 10:28:01 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-13 10:48:24 +0200 |
| commit | c01b244ad848ac7f0faa141182db80650a8a761a (patch) | |
| tree | 5e6fbad5316fc3915609e013fc1875ff36af0d64 /drivers/usb/core/devio.c | |
| parent | 81606aea2303aa11867e97030299b1057091c2fd (diff) | |
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: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Reinhard Huck <reinhard.huck@thesycon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core/devio.c')
| -rw-r--r-- | drivers/usb/core/devio.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 8e6ef671be9b..0e7d0e81a7cb 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -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: |