Hardware #

NVIDIA WIRED VR ISSUES: Nvidia proprietary drivers currently have a critical issue with DRM lease causing substantial presentation latency for wired VR headsets, resulting in a delayed viewport effect that makes VR uncomfortable. This affects all known supported driver versions. Wireless VR through WiVRn is entirely unaffected only direct display type wired headsets. Users with Nvidia GPUs should consider the Nvidia Wired VR Workaround footnotes of the GPU table below or switch to AMD for the best experience. For details and to report your experience, see this forum thread.

GPU support matrix #

Notes:

• VR Support: Indicates how well supported the necessary Vulkan API components are.
• Reprojection Support: Describes the support and quality of reprojection features for VR. Poor support indicates that the driver is not able to properly handle Vulkan realtime shaders and it will present as visual stutter. Non-robust solutions will suffer stutter under very high GPU load.
• PRIME/ Hybrid GPU Support: Compatibility with systems using multiple GPUs for render offload. Monado and all clients must be run on a single select GPU due to memory tiling requirements.
• For Nvidia proprietary drivers older than 565, (please try to update!), the vulkan-layers must be installed in order to not crash: AUR・Fedora
• Nvidia Wired VR Workaround: Wired users should certainly set XRT_COMPOSITOR_USE_PRESENT_WAIT to 1 which changes the swapchain to explicit sync behavior and U_PACING_COMP_TIME_FRACTION_PERCENT to 90, representing 90% of the time it takes to render a frame can significantly reduce the latency effect with Nvidia GPUs. There are notable frametime issues in the driver still which may result in stutter but this should vastly improve the experience.
• Nvidia GPUs work well for wireless VR through WiVRn.
• AMD GPUs lower than RDNA generation have functional but less robust reprojection capabilities, expected to be similar to Intel.
• Audio over displayport is known to temporarily cut out when new audio sources spring up on pipewire without a fix to add alsa headroom
• X11 configurations are discouraged but workable, please upgrade your system to Wayland if at all possible.

XR Devices #

A non-comprehensive table of various VR/XR devices and the drivers that support them. Note that wired headset experiences with Nvidia GPUs will be affected by the DRM lease presentation latency issue.

Hardware note #

• Nvidia GPU users: Due to the DRM lease presentation latency issue, wired VR headsets will experience a delayed viewport effect on Nvidia GPUs. This affects all driver versions since 550. Consider these workarounds:
  • Use WiVRn or ALVR with standalone headsets for wireless VR (recommended)
  • Try setting U_PACING_COMP_MIN_TIME_MS=10 as an environment variable to slightly reduce the effect
  • Consider switching to AMD GPUs for the best wired VR experience
  • Monitor the bug report thread for updates
• AMD GPU users: If using WiVRn, make sure you are using the RADV Vulkan driver. A green and broken video stream in WiVRn is a telltale sign that you’re using the incompatible AMDVLK driver. Remove AMDVLK and install RADV as AMDVLK is known to be difficult to opt out of as a driver when installed on system.
• WiVRn PC XR to WiVRn PC client streaming remains mainly for debug use.
• Vive Pro microphones should be set to use 44.1khz sample rates as feeding in 48khz raises the pitch of the audio.
• Vive Pro creates HDMI Output Source after startup of SteamVR/Monado/etc. Use it instead of Vive Pro USB Audio Source, since the audio might appear distorted.
• Valve Index audio output should be set to 48khz or no audio will output.
• Valve Index may bug out once per boot, resulting in VR refusing to start, or your DE seeing it as a normal monitor. Just unplug and replug the barrel connector that provides power to the HMD.
• Valve Index may also exhibit unexpected activity with its microphone. If the microphone doesn’t transmit at all during regular VR use, consider changing the DisplayPort slot the headset is currently plugged into. Also, as a reminder, the Index mic only works if the headset is actively being used to display something.
• Vive Pro Eye HMD functional, eye tracking functionality with ReVision
• Pimax initialization code WIP. Distortion matrix dump work in progress.
• Eyetrack VR and Project Babble will both be implemented through oscavmgr to emit proper unified flexes over OSC.
• Tracking technologies can be mixed Monado/WiVRn by using motoc.
• Having Ultraleap packages installed causes Monado to not compile.

Applying a kernel patch (for Vive Pro 2, Bigscreen Beyond, Pimax) #

Arch #

1. download the patch(es), then follow the steps on https://wiki.archlinux.org/title/Kernel/Arch_build_system, which should be roughly: mkdir ~/build/ -> cd ~/build/ -> pkgctl repo clone --protocol=https linux -> cd linux
2. (section 2 of link) open PKGBUILD in that directory and modify the pkgbase line (at the top) to read e.g. “pkgbase=linux-customvr”. then add a line containing “<patchfilename>.patch” to the source array:

source=(
  https://cdn.kernel.org/pub/linux/kernel/v${pkgver%%.*}.x/${_srcname}.tar.{xz,sign}
  <patchfilename>.patch
  $url/releases/download/$_srctag/linux-$_srctag.patch.zst{,.sig}
  config  # the main kernel config file
)

4. close PKGBUILD. (may not be necessary but i ran updpkgsums) -> makepkg -s --skippgpcheck (i didn’t feel like fixing a pgp error)
5. then section 4 of https://wiki.archlinux.org/title/Kernel/Arch_build_system#Installing and restart

Fedora #

1. Prepare the kernel

git clone https://src.fedoraproject.org/rpms/kernel.git
cd kernel

# replace 41 with your fedora version
git switch f41

# install the build dependencies for the kernel, if you haven't already
sudo dnf builddep kernel.spec

# name this the 'bsb' build
sed -i 's/# define buildid .*/%define buildid .bsb/g' kernel.spec

2. Replace linux-kernel-test.patch with the actual patch file downloaded from the table above

3. Build RPMs:

fedpkg local

4. Install kernel:

sudo dnf install --nogpgcheck ./x86_64/kernel-*.rpm

5. Reboot and check that using uname -a that the bsb kernel is running.

Official guide: Building a Kernel from the Fedora dist-git

NixOS #

1. download the patch(es)
2. add this to your configuration.nix or other nix file you use:

  boot.kernelPatches = [
    {
      name = "type what the patch is for here";
      patch = /path/to/patch/file.patch;
    }
  ];

reference commit on my nix files: https://github.com/TayouVR/nixfiles/commit/d6ef568a2642c5a26eb92611be7335afdb6047de