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Commit 3f141e2a authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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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: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent d1bbb600

drivers/usb/core/devio.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

drivers/usb/core/generic.c

+1 −1
Original line number Diff line number Diff line
@@ -184,7 +184,7 @@ static void generic_disconnect(struct usb_device *udev) 
	/* if this is only an unbind, not a physical disconnect, then

	 * unconfigure the device */

	if (udev->actconfig)

		usb_set_configuration(udev, 0);

		usb_set_configuration(udev, -1);



	usb_remove_sysfs_dev_files(udev);

}

drivers/usb/core/message.c

+18 −4
Original line number Diff line number Diff line
@@ -1316,6 +1316,14 @@ static void release_interface(struct device *dev) 
 * use this kind of configurability; many devices only have one

 * configuration.

 *

 * @configuration is the value of the configuration to be installed.

 * According to the USB spec (e.g. section 9.1.1.5), configuration values

 * must be non-zero; a value of zero indicates that the device in

 * unconfigured.  However some devices erroneously use 0 as one of their

 * configuration values.  To help manage such devices, this routine will

 * accept @configuration = -1 as indicating the device should be put in

 * an unconfigured state.

 *

 * USB device configurations may affect Linux interoperability,

 * power consumption and the functionality available.  For example,

 * the default configuration is limited to using 100mA of bus power,
@@ -1347,18 +1355,24 @@ int usb_set_configuration(struct usb_device *dev, int configuration) 
	struct usb_interface **new_interfaces = NULL;

	int n, nintf;



	if (configuration == -1)

		configuration = 0;

	else {

		for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {

		if (dev->config[i].desc.bConfigurationValue == configuration) {

			if (dev->config[i].desc.bConfigurationValue ==

					configuration) {

				cp = &dev->config[i];

				break;

			}

		}

	}

	if ((!cp && configuration != 0))

		return -EINVAL;



	/* The USB spec says configuration 0 means unconfigured.

	 * But if a device includes a configuration numbered 0,

	 * we will accept it as a correctly configured state.

	 * Use -1 if you really want to unconfigure the device.

	 */

	if (cp && configuration == 0)

		dev_warn(&dev->dev, "config 0 descriptor??\n");

drivers/usb/core/sysfs.c

+1 −1
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ set_bConfigurationValue(struct device *dev, struct device_attribute *attr, 
	struct usb_device	*udev = to_usb_device(dev);

	int			config, value;



	if (sscanf(buf, "%u", &config) != 1 || config > 255)

	if (sscanf(buf, "%d", &config) != 1 || config < -1 || config > 255)

		return -EINVAL;

	usb_lock_device(udev);

	value = usb_set_configuration(udev, config);