Passing through more than 8/12 USB devices

[Makki]

Hi there,

while testing I found that no more than 8 - with XHCI, 12 with EHCI - USB-devices (concurrently) could be passed through to a VM.
The error-message thrown by vbox when connecting #9 is:

Failed to create a proxy-device for the USB device. (VERR_PDM_NO_USB_PORTS)

Now, so far so bad, this seems to be a limitation ?
Question is: How "hard" is this limitation and is it possible to raise this to 32 (even by changing source and recompile) ?

P.S.: The application here is mass-updating devices over USB, up to 32 devices..

thanks, Makki

[Perryg]

Which chipset are you using for the guest, piix3 or ich9?

[Makki]

Uh, default PIIX3

[Perryg]

What happens if you switch?

[Makki]

Sorry, I couldn't test right now in train, but will ASAP;
But this sounds like its no generic limitation (?)

[Makki]

@Perryg Thank you so much for the hint!!
I'd never would have thought about the chipset..

Switching PIIX3->ICH9: successfully with 17 devices / EHCI(USB2.0)
(XHCI still max. 7 but I dont care in this case, as there is no need for XHCI.. btw.: OHCI/USB1.1 is also still max. 12)

-> I'll do further tests on Monday and report.. I'm out of USB2-Hubs at home

Makki