[Spice-devel] Limitation on the number of USB devices supported at the same time

[Hans de Goede]

Hi,

On 10/12/2012 04:03 PM, 李彪 wrote:
> hi,
>
> we are using spicy to share the USB devices between thin client and VM in Server.
> however, it shows that
>
> -  the menu of spicy can show more than 5 detected USB devices
> -  if enable more than 5 USB devices, spicy will prompt the error of out of number of supported USB devices.
>
> I am not sure is there implement limitation in spicy source code ? or this issue can be avoided by changing build configuration ?

The limitation comes from the number of usb-channels / usb-redir devices configured on the
qemu cmdline / inside libvirt

The ehci controller has 6 ports, so if you remove any virtual usb-devices such as a usb-tablet,
you can configure one more channel. For more channels you need to add a second ehci controller
+ companions. Alternatively you could configure the ehci controller to have more ports,
but I think that requires qemu source-code changes atm.

Regards,

Hans