USB 2.0 Quick Start
===================

The QEMU EHCI Adapter does *not* support companion controllers.  That
implies there are two completely separate USB busses: One USB 1.1 bus
driven by the UHCI controller and one USB 2.0 bus driven by the EHCI
controller.  Devices must be attached to the correct controller
manually.

The '-usb' switch will make qemu create the UHCI controller as part of
the PIIX3 chipset.  The USB 1.1 bus will carry the name "usb.0".

You can use the standard -device switch to add a EHCI controller to
your virtual machine.  It is strongly recommended to specify an ID for
the controller so the USB 2.0 bus gets a individual name, for example
'-device usb-ehci,id=ehci".  This will give you a USB 2.0 bus named
"ehci.0".

I strongly recomment to also use -device to attach usb devices because
you can specify the bus they should be attached to this way.  Here is
a complete example:

    qemu -M pc ${otheroptions}                           \
        -drive if=none,id=usbstick,file=/path/to/image   \
        -usb                                             \
        -device usb-ehci,id=ehci                         \
        -device usb-tablet,bus=usb.0                     \
        -device usb-storage,bus=ehci.0,drive=usbstick

This attaches a usb tablet to the UHCI adapter and a usb mass storage
device to the EHCI adapter.

enjoy,
  Gerd

--
Gerd Hoffmann <kraxel@redhat.com>