Hi, Gerd
I'm still trying to realize local live-migration with usb passthrough devices
for purpose of upgrading qemu.
I've make sure source and target vms will not access host usb devices at the
same time.
But when I test USB flash disk copying files during live-migration stage, I
encounter a
probabilistic<http://www.baidu.com/link?url=g4qrOrKnI-sBjfjxYNxmXKZxrV7jJuwP19NuGzgK_v_28EpnAtaqUaZQEiv32l9VWE9lynyG8amn0_IPEI7xcnGdT-YF8zuUIy82P1euVr_>
problem: copying task may stuck for a while.
This problem happened just after source vm stoping and target vm starting to
run, which caused by the long time pending transfer.
In other words, target vm submit the first bulk transfer may not trigger
callback function. I cannot figure out whether it is a usb driver's bug.
Could give me some advice or whether you have met the same problem before?
