USB-C controller passthrough working but webcam stops working after a time (Intel i9-9900k)


Nov 10, 2020
Hello everyone, I have a puzzling and annoying USB controller passthrough issue, specifically with my webcam. I’m not sure where to start to fix this issue so I’d like to see if the forum can guide me to try and resolve it as it’s literally the only issue I have with an otherwise smooth system.

In short, my USB-C webcam (Logitech StreamCam) works fine on both MacOS and Windows after a fresh restart of the Proxmox server. I could stay on a video call for as long as I want and it’s fine. However, if I tried to use the camera later in the day, it simply either isn’t recognised or is jerky and flickers (Examples linked).

As far as I am aware, the USB controller on my Intel i9 9900k is on a dedicated IOMMU group and has been correctly passed through and the BIOS on my Gigabyte Designare is correctly set up but I would like to validate this with your assistance.

This is my motherboard if it helps diagnose the issue.

My BIOS version is a few versions out of date (Link to BIOS versions here, I will validate which one I am ASAP but it's no earlier than F6) but I would like to double-check everything before upgrading the BIOS as I’m nervous I’ll be able to get it back how it was as I had help setting this server up. Of course, if that is the guidance then I'll do so.

Any guidance will be welcomed. Also, if we deem my setup is fine, I am happy to buy a USB-C PCIe card to test and suggestions on a card would be great.

Videos showing issues in 2 different software.

Logitech StreamCam settings with issues
Google Meet screen with issues

Some setup information:

Proxmox version 6.2-12
MacOS version 11.6 (But also see this issue on 10.14) - Via Opencore, also have used Clover and seen the issue
Windows 10 - Rarely used but validated the issue exists

Not sure you'll need all this but here is the output from pveversion -v

proxmox-ve: 6.2-2 (running kernel: 5.4.65-1-pve)
pve-manager: 6.2-12 (running version: 6.2-12/b287dd27)
pve-kernel-5.4: 6.2-7
pve-kernel-helper: 6.2-7
pve-kernel-5.4.65-1-pve: 5.4.65-1
pve-kernel-5.4.34-1-pve: 5.4.34-2
ceph-fuse: 12.2.11+dfsg1-2.1+b1
corosync: 3.0.4-pve1
criu: 3.11-3
glusterfs-client: 5.5-3
ifupdown: 0.8.35+pve1
ksm-control-daemon: 1.3-1
libjs-extjs: 6.0.1-10
libknet1: 1.16-pve1
libproxmox-acme-perl: 1.0.5
libpve-access-control: 6.1-3
libpve-apiclient-perl: 3.0-3
libpve-common-perl: 6.2-2
libpve-guest-common-perl: 3.1-3
libpve-http-server-perl: 3.0-6
libpve-storage-perl: 6.2-8
libqb0: 1.0.5-1
libspice-server1: 0.14.2-4~pve6+1
lvm2: 2.03.02-pve4
lxc-pve: 4.0.3-1
lxcfs: 4.0.3-pve3
novnc-pve: 1.1.0-1
proxmox-backup-client: 0.9.0-2
proxmox-mini-journalreader: 1.1-1
proxmox-widget-toolkit: 2.3-1
pve-cluster: 6.2-1
pve-container: 3.2-2
pve-docs: 6.2-6
pve-edk2-firmware: 2.202002-1
pve-firewall: 4.1-3
pve-firmware: 3.1-3
pve-ha-manager: 3.1-1
pve-i18n: 2.2-1
pve-qemu-kvm: 5.1.0-3
pve-xtermjs: 4.7.0-2
qemu-server: 6.2-15
smartmontools: 7.1-pve2
spiceterm: 3.1-1
vncterm: 1.6-2
zfsutils-linux: 0.8.4-pve2

This is the result of the qm config for my MacOS VM (With some minor details removed)

args: -device -smbios type=2 -device usb-kbd,bus=ehci.0,port=2 -smp 12,sockets=3,cores=2,threads=2 -cpu host,kvm=on,vendor=GenuineIntel,+kvm_pv_unhalt,+kvm_pv_eoi,+hypervisor,+invtsc
balloon: 0
bios: ovmf
boot: cdn
bootdisk: virtio0
cores: 12
cpu: Penryn
efidisk0: local-zfs:vm-103-disk-0,size=1M
hostpci0: 3b:00.0,pcie=1
hostpci1: 01:00,pcie=1,x-vga=1
machine: q35
memory: 30720
name: MacOs-BigSur-Template
numa: 0
onboot: 1
ostype: other
scsihw: virtio-scsi-pci
sockets: 1
usb0: host=removed
usb1: host=removed
usb2: host=removed
usb4: host=removed
vga: none

Many thanks,
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