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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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern 2007-02-08 16:40:43 -05:00 committed by Greg Kroah-Hartman
parent d1bbb60007
commit 3f141e2aed
4 changed files with 22 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/usb/core/devio.c
View File

@ -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;

2
drivers/usb/core/generic.c
View File

@ -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);
}

22
drivers/usb/core/message.c
View File

@ -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,
@ -1347,10 +1355,15 @@ int usb_set_configuration(struct usb_device *dev, int configuration)
struct usb_interface **new_interfaces = NULL;
int n, nintf;
for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
if (dev->config[i].desc.bConfigurationValue == configuration) {
cp = &dev->config[i];
break;
if (configuration == -1)
configuration = 0;
else {
for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
if (dev->config[i].desc.bConfigurationValue ==
configuration) {
cp = &dev->config[i];
break;
}
}
}
if ((!cp && configuration != 0))
@ -1359,6 +1372,7 @@ int usb_set_configuration(struct usb_device *dev, int configuration)
/* 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");

2
drivers/usb/core/sysfs.c
View File

@ -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);