[libvirt-users] Constantly changing USB product ID

Jaap Winius
Tue, 27 Mar 2012 22:09:25 -0000

Hi folks,

Recently I learned how to configure libvirt with USB pass-though
functionality. In my case I configured my guest domain with this block
of code:

     <hostdev mode='subsystem' type='usb'
managed='yes'>

         <vendor id='0x0c93'/>
         <product id='0x1772'/>


     </hostdev>

At first this worked fine, but then later the guest domain refused to
start because the USB device was absent. When I checked, I found that
its product ID had mysteriously changed to 1771. Later it was back at
1772. Now it appears that the USB device I am dealing with has a
product ID that changes back and forth between 1771 and 1772 at random.

Apparently, the Windows program running on the guest domain is
designed to deal with this nonsense, but the question is, Can the
guest domain be configured to deal with it? Something like <product
id='0x177?'/> would be useful, but that doesn't work, nor does
omitting the product tag.

Any ideas would be much appreciated.

Thanks,

Jaap