[libvirt] [PATCH 04/17] Add a test for long USB port paths

[Ján Tomko]

On Mon, Jun 20, 2016 at 08:50:31AM +0200, Gerd Hoffmann wrote:
>On Fr, 2016-06-17 at 20:07 +0200, Ján Tomko wrote:
>> For some reason, we support up to four levels of nested USB devices
>> in the guest.
>
>FYI: The reason is simply that usb is specified that way.  You can't
>chain usb hubs endlessly.
>

I was under the impression that 7 is the maximum depth.

I see that QEMU errors out at 6 levels for a USB hub:
qemu-git: -device usb-hub,port=1.1.1.1.1.1: usb hub chain too deep

So perhaps up to 6 levels could be allowed for regular devices?

Jan