From 3f141e2aed586c41c2666d49c70c1c1bbb6d6abd Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Thu, 8 Feb 2007 16:40:43 -0500 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/devio.c | 4 ++-- drivers/usb/core/generic.c | 2 +- drivers/usb/core/message.c | 22 ++++++++++++++++++---- drivers/usb/core/sysfs.c | 2 +- 4 files changed, 22 insertions(+), 8 deletions(-) diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 2087766f9e..274f14f163 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; diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c index b531a4fd30..9bbcb20e2d 100644 --- a/drivers/usb/core/generic.c +++ b/drivers/usb/core/generic.c @@ -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); } diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 8aca3574c2..74edaea566 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -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"); diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c index 4eaa0ee8e7..0edfbafd70 100644 --- a/drivers/usb/core/sysfs.c +++ b/drivers/usb/core/sysfs.c @@ -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); -- 2.39.5