Re: [Qemu-devel] Mixed USB 1.1 and USB 2.0 on the same port

[Hans de Goede]

On 01/04/2012 05:52 PM, Erik Rull wrote:
> address@hidden wrote:
> > > On 12/31/11 13:11, Erik Rull wrote:
> > > > Hi all,
> > > >
> > > > how can I use a USB 1.1 device on the USB 2.0 bus? Currently the EHCI
> > > > implementation complains that the device is mismatches the USB version.
> > >
> > > -readconfig docs/ich9-ehci-uhci.cfg
> > >
> > > cheers,
> > > Gerd
> >
> > Thanks for the hint.
> >
> > It looks better now. But some things are still a bit strange.Hi,
> >
> > Sequence:
> > device_add usb-host,bus=ehci.0,hostbus=2,hostport=1.4
> > Plug in a USB 2.0 printer
> > (gets detected by the guest, printing is possible, no bluescreen, it just
> > works)
> > Remove the USB 2.0 printer
> > Plug in a USB 1.1 dongle
> > Gets detected, etc., fine
> > Remove the USB 1.1 dongle
> > Plug in the USB 2.0 printer again
> > Guest complains now, that a USB 2.0 device was plugged into a USB 1.1 port
> > => printer is now 1.1 and does not work as if EHCI is missing now
> > => reboot guest, everything is fine again??
> >
> > Any idea what could have happened here?
> > Same behavior when using a 2.0 USB key and the USB 1.1 dongle - also on
> > other ports - the transfer rate is horrible after having removed the USB
> > 1.1 device and reconnected the 2.0 device.
> > Exchanging the two USB 2.0 devices on the same port without having the 1.1
> > device plugged in is fine!
> >
> > Any hint what is wrong here would be great.
> >
> > Best regards,
> >
> > Erik
>
> Additional Information:
> This behavior is present on a Linux guest as well! After having removed the 1.1 
> Dongle and plugged in the printer, the Linux guest detects the hardware via the 
> UHCI kernel drivers and tells me to use a faster hub for max. performance.
> It looks as if the speed downgrade by the 1.1 device cannot be reversed at 
> runtime.

I've managed to reproduce this and written a fix for it. I've just send
a patch for this to the list. I've also attached this patch here for
your convenience.

Regards,

Hans

0001-usb-ehci-Clear-the-portstatus-powner-bit-on-device-d.patch
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