Since there hasn't been any response to the question in comment #1, and version 0.13 is very outdated nowadays, I'm closing this ticket now. If you've still got USB problems with the very latest version of QEMU, please feel free to re-open this ticket again, or open a new ticket instead.
** Changed in: qemu Status: New => Won't Fix -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/645524 Title: No picture from USB webcam (kvm 0.13-rc1) Status in QEMU: Won't Fix Bug description: I export my Linux webcam to KVM using the switches "-usb -usbdevice host:046d:0929". The XP guest sees the webcam and the drivers install, but the camera only shows a black image. When I open the camera in Windows Explorer, it says "0 images" and a black image, while on a real XP, it says "1 image" and shows the video from the camera. Same problem with different webcams. Same cameras work fine on a native XP install. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/645524/+subscriptions