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authorHindin Joseph <hindin@gmail.com>2012-11-05 00:50:08 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-11-16 04:56:22 +0400
commitc13b86a336d089f248293776a853252fbca15c26 (patch)
tree6eb97e2f67f4a08c68ea5dbe01bfe99bdfb16c66 /drivers/usb/core
parent9d94e16be70d34d139ec3c7882ed0283b5ac074d (diff)
downloadlinux-c13b86a336d089f248293776a853252fbca15c26.tar.xz
USB: fix authorization and claimed port logic
It looks like I've run into some inconsistency in the USB stack behavior. The USB stack maintains, among others, two states for the attach USB device: authorized and owned. Authorization state is accessible to the user space code through correspondent sysfs files, the ownership can be set by claiming the hub's port with ioctl call. Both state may be set before the device is attached, by access the hub settings. When the new device is attached, both authorization and ownership prevent the kernel USB stack from setting the newly attached device configuration, but when the device is authorized, the ownership state is ignored. It looks like ignoring the ownership state on authorization make the stack behavior inconsistent; it also prevents the user space code from completely overriding configuration selection, important for implementing workarounds for bugs in the device configuration selection. The following patch makes the stack behavior more consistent, by moving ownership test into usb_choose_configuration - the later function is used both by generic_probe and usb_authorize_device Signed-off-by: Joseph Hindin <hindin@gmail.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core')
-rw-r--r--drivers/usb/core/generic.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c
index 69ecd3c92311..eff2010eb63f 100644
--- a/drivers/usb/core/generic.c
+++ b/drivers/usb/core/generic.c
@@ -47,6 +47,9 @@ int usb_choose_configuration(struct usb_device *udev)
int insufficient_power = 0;
struct usb_host_config *c, *best;
+ if (usb_device_is_owned(udev))
+ return 0;
+
best = NULL;
c = udev->config;
num_configs = udev->descriptor.bNumConfigurations;
@@ -160,9 +163,7 @@ static int generic_probe(struct usb_device *udev)
/* Choose and set the configuration. This registers the interfaces
* with the driver core and lets interface drivers bind to them.
*/
- if (usb_device_is_owned(udev))
- ; /* Don't configure if the device is owned */
- else if (udev->authorized == 0)
+ if (udev->authorized == 0)
dev_err(&udev->dev, "Device is not authorized for usage\n");
else {
c = usb_choose_configuration(udev);