2010/5/14 Greg KH <greg@xxxxxxxxx>: > On Fri, May 14, 2010 at 09:44:52PM +0800, tom.leiming@xxxxxxxxx wrote: >> From: Ming Lei <tom.leiming@xxxxxxxxx> >> >> For root-hub devices, we don't support the 'remove' action, >> but deconfiguration may cause root-hub to stop work even >> usb_remove_device returns failure. >> >> Considered it is very similar to remove a usb device by >> usb_remove_device only, compared with physical disconnection processing. >> >> There are no races conditions found if only usb_remove_device is >> called to do 'remove' action without deconfiguration, so remove >> the deconfiguration to fix it. >> >> Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx> > > Have you had problems with the root hub being disabled? Why would this Once you call 'echo 1 > /sys/bus/usb/devices/usbN/remove', the root-hub (usbN) will not detect any devices connected into the hub any longer but failure is returned for the 'echo 1 > remove' command. > cause them to stop working? What tool is trying to remove a root hub? The reason is that usb_set_configuration(udev, -1) is called before usb_remove_device even though usb_remove_device doesn't support remove of root-hub. > Why not just fix that tool? As far as kernel is concerned, we should provide a safe interface to user, and must prevent a disaster from happening even a mistaken command is sent to kernel, shouldn't we? thanks, -- Lei Ming -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
