Cannot add a USB 2.0 device under QEMU when running eudev

[Francesco Turco]

Hello.

I have a USB webcam I'm using under QEMU (version 1.6.1). The guest is Windows 7 (32-bit) while the host is Gentoo Linux (64-bit). I have been using it for several weeks without any problem, but now it doesn't work any more. I have been able to pinpoint the cause: it is because I switched from udev-208 to eudev-1.3 (which is based on udev-207).

These are the command line options for QEMU:

qemu-system-i386 -cpu host -m 1G -k it -drive file=Windows_7.qcow2,media=disk,index=0 -vga std -net nic -net user -enable-kvm -display sdl -soundhw ac97 -device usb-ehci,id=ehci -usb -rtc base=localtime -usbdevice tablet

The relevant options are -device usb-ehci,id=ehci -usb. That is, I'm enabling both USB 2.0 (EHCI) and USB 1.1 (UHCI). I manually add the webcam using: device_add usb-host,hostbus=x,hostaddr=y,id=webcam but if I do so when running eudev it gets added as a slow USB 1.1 1.5 Mb/s device:

(qemu) info usb
  [...]
  Device 1.0, Port 1, Speed 1.5 Mb/s, Product USB Host Device

I also noticed that the "info usbhost" command works differently now, in that it doesn't display any more a description, such as the brand name (Creative):

(qemu) info usbhost
  [...]
  Bus 1, Addr 3, Port 3, Speed 480 Mb/s
  Class ef: USB device 041e:4088

From the host system:

$ lsusb | grep Creative
Bus 001 Device 003: ID 041e:4088 Creative Technology, Ltd Live! Cam Chat HD [VF0700]

If I turn back to udev I get the following results instead:

(qemu) info usb
  [...]
  Device 1.1, Port 1, Speed 480 Mb/s, Product VF0700 Live! Cam Chat HD

(qemu) info usbhost
  [...]
  Bus 1, Addr 2, Port 4, Speed 480 Mb/s
  Class ef: USB device 041e:4088, VF0700 Live! Cam Chat HD

I don't know if this is a problem with QEMU or with eudev, so I'm also going to report this bug on the Gentoo Bugzilla (eudev is a Gentoo project).

[Francesco Turco (fturco)]

Please also see https://bugs.gentoo.org/show_bug.cgi?id=494946

[Francesco Turco (fturco)]

I just tried with eudev-1.4, but I get the same problem as with version 1.3.

[Francesco Turco (fturco)]

The bug has been fixed. It had nothing to do with QEMU. The problem was that eudev didn't ship a file with rules for USB devices. See https://bugs.gentoo.org/show_bug.cgi?id=499236 for detais. Sorry for the noise.