Re: [usb] usb 3.0 bandwidth insufficient

[Toerless Eckert]

I tried to get the NVidia 3D glasses IR emitter to work for windows 10
in KVM (before NVidia F***ed with 3D fans and removed all support for
it from their drivers). No performance, but low-latency USB signalling
problem, delay through qemu was just miserable.

I ended up buying a mini-PCIe USB3 card so that i had a separate 
PCI USB controller rom the one on the motherboard and then passed
that PCI controller through to the VM. Works fine.
(mini-PCIe was the only free slot on my mini-ITX MoBo).

Would expect there is also no performance degradation when using
passthrough.

Cheers
    Toerless

On Thu, Feb 27, 2020 at 12:39:04PM -0500, Peter Geis wrote:
> Good Afternoon,
> 
> I have been trying to pass through a usb capture card over usb 3.0 to
> a windows vm.
> The device requires 90% of actual usb 3.0 bandwidth, as it captures
> native 1080p 60fps video.
> Unfortunately it seems the qemu usb controller cannot provide this, as
> the device fails to provide video at 1080p.
> 
> I'm trying to find a way to debug this and have not had much success,
> can anyone point me in a direction to check?