I upgraded xen-hvm-stubdom-linux on a vanilla install of Qubes 4.1, rebooted, and now USB passthrough does not work at all. lsusb of dom0 shows no devices, and in sys-usb it only shows the hubs.
Sorry. I’m new to bug reporting, and don’t know what exactly you need.
What information/logs do you need from my machine?
That’s a great question. I feel like a guide on what looks are important for which components could be a good thing! I sometimes also struggle with that.
Which version of xen-hvm-stubdom-linux package specifically? Can you give full output of rpm -q xen-hvm-stubdom-linux?
Consider it done, my good sir 
xen-hvm-stubdom-linux-1.2.3-1.52.fc32.x86_64
What else do you need?
Ok, it seems you installed it from qubes-dom0-unstable repository. I strongly recommend disabling it. As the name suggests, it contains packages that may not work (this is one of them). It may be useful only for getting specific packages when explicitly requested (and then - enabled only temporarily, with --enablerepo option).
For the fix, downgrade to a stable version: qubes-dom0-update --action=downgrade xen-hvm-stubdom-linux, you should get version either 1.2.3-1 or 1.2.2-1.
Not a problem. I was testing it for you guys. That’s why I was using the unstable repo. I’ll downgrade.
Hopefully this helps the devs in some way.
Thanks @marmarek !
PS: Would any logs help at all? I’m asking because I’ve got machines that 1.2.3-1.52 works perfectly on, and some that it doesn’t…
That package has broken MSI-X support, so only devices that use MSI-X are affected.
Not a problem. All good.