[Qemu-discuss] ehci: ASYNC list address register set while async schedule is enabled and HC is enabled

[Jean-Marc Saffroy]

Hi,

I'm trying to use a USB2 scanner inside a WinXP guest under qemu/kvm on a 
Linux host. I use the following command:

$ qemu-system-x86_64 -enable-kvm -m 1024 -smp 2 -net nic -net user -vga 
std -readconfig /home/saffroy/tmp/qemu-1.4.0/docs/ich9-ehci-uhci.cfg 
-device usb-host,vendorid=0x04b8,productid=0x012a,bus=ehci.0 -hda 
winxp-qcow2.img -snapshot

The Windows guest detects the scanner, but the scanner software fails to 
actually use it (it reports obscure errors suggesting low level problems), 
and qemu prints this message many times:

ehci: ASYNC list address register set while async schedule
      is enabled and HC is enabled

This is qemu 1.4.0, hand built on Debian squeeze (+ some backports + 
vanilla kernel 3.7.3).

The scanner works from the Linux host (with limited features, hence the 
need to use Windows), and the same scanner software used to work from a 
non-virtualized Windows host, so it really looks like a problem caused by 
my use of qemu.

Any ideas?


Cheers,
Jean-Marc

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