USB: unconfigure devices which have config 0

Some USB devices do have a configuration 0, in contravention of the
USB spec.  Normally 0 is supposed to indicate that a device is
unconfigured.

While we can't change what the device is doing, we can change usbcore.
This patch (as852) allows usb_set_configuration() to accept a config
value of -1 as indicating that the device should be unconfigured.  The
request actually sent to the device will still contain 0 as the value.
But even if the device does have a configuration 0, dev->actconfig
will be set to NULL and dev->state will be set to USB_STATE_ADDRESS.

Without some sort of special-case handling like this, there is no way
to unconfigure these non-compliant devices.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 2087766f9e88..274f14f1633e 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -857,11 +857,11 @@ static int proc_setintf(struct dev_state *ps, void __user *arg)
 
 static int proc_setconfig(struct dev_state *ps, void __user *arg)
 {
-        unsigned int u;
+        int u;
         int status = 0;
         struct usb_host_config *actconfig;
 
-        if (get_user(u, (unsigned int __user *)arg))
+        if (get_user(u, (int __user *)arg))
                 return -EFAULT;
 
         actconfig = ps->dev->actconfig;