On Sun, 4 Nov 2012, Hindin Joseph wrote: > 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 <[email protected]>
Good work finding this problem. Acked-by: Alan Stern <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
