GPU Passthrough and VR headsets

DvdLSK

New Member
Dec 4, 2025
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Hi, hoping to see that someone could shed some light on this.

I’ve got a VM setup successfully with GPU passthrough running on ProxMox 8.4.0. My next goal was to see if I could get a VR headset working (a HTC Vive Pro 2 in this case).
To make this possible with all the extra USB controllers that a VR headset makes I’ve added a USB PCI card and passed that through to the VM. This also worked a treat.
Now comes the annoying part, I can’t get the headset working. The error that I get from Steam VR is: Your GPU can’t successfully connect to your HMD display. But it does recognise everything else. This is also the case for other VR headsets I’ve tried..

I’ve scoured the forums for all the tips & tricks for GPU passthrough and implemented a whole bunch of them without any change in error messages.
Changes I’ve done:
/etc/default/grub
Code:
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on iommu=pt pcie_acs_override=downstream,multifunction nofb nomodeset video=vesafb:off,video=efifb:off"

/etc/modprobe.d/vfio.conf
Code:
options vfio-pci ids=10de:2702,10de:22bb disable_vga=1

/etc/modprobe.d/blacklist.conf
Code:
blacklist nouveau
blacklist nvidia
blacklist nvidiafb
blacklist i915

/etc/modprode.d/kvm.conf
Code:
options kvm ignore_msrs=1

/etc/modprobe.d/iommu_unsafe_interrupts.conf
Code:
options vfio_iommu_type1 allow_unsafe_interrupts=1

Both the GPU and PCI USB card have been fully assigned to the VM with everything enabled.

Would love to hear if someone has dabbled with VR and ProxMox in combination.