On 03/28/2012 02:41 PM, Avi Kivity wrote:

On 03/27/2012 05:48 PM, Jaap Winius wrote:

...

Hi folks,

Recently I learned how to configure KVM 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'> <source> <vendor id='0x0c93'/> <product id='0x1772'/> <address bus='1' device='4'/> </source> </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 KVM be configured to deal with it? Something like <product id='0x177*'/> would be useful, but that doesn't work.

Any ideas would be much appreciated.

This is really strange. What kind of device is this?

I've filed an RFE [1] for virt-manager for assigning USB host devices opportunistically, that is if they're plugged they're assigned, and if not the guest starts without them. If it were implemented, you could assign both 0x1771 and 0x1772 and whichever ID the device is today would get assigned.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=804432

btw, the correct place for this discussion is likely the libvirt mailing list, or maybe the virt-manager list if it exists. -- error compiling committee.c: too many arguments to function