From https://bugs.launchpad.net/ubuntu/+source/kvm/+bug/156085/comments/6, we can see, it's truned to use /dev/bus/usb, why not turn to use this one as a fix?
From https:/ /bugs.launchpad .net/ubuntu/ +source/ kvm/+bug/ 156085/ comments/ 6, we can see, it's truned to use /dev/bus/usb, why not turn to use this one as a fix?