[BUG] Delayed Headset Tracking compared to Windows

[issacdowling]

Describe the bug Sorry for the not super descriptive title, but I just can't quite place what's happening. It happens on both an original HTC Vive with stock SteamVR, and a Vive Pro 2 with the community-made Linux drivers (which I could understand not wanting to support, but it is exactly the same on the original Vive too). My controllers appear to track perfectly with no noticeable jitter or latency, but the headset movement feels a little bit behind - however, using a slow motion camera, I confirmed that the video feed is not actually delayed, as it presents the desktop view earlier than my HFR monitor - and it's a little bit too shaky. On Windows, these issues don't occur with either headset.

To Reproduce Use a HTC Vive or Vive Pro 2 (this headset uses community-made drivers on Linux, the Vive doesn't though) on Linux, move your head side-to-side to see the delay, or stand still and notice the higher jitter.

Expected behavior I expect tracking to feel the same as Windows.

System Information (please complete the following information):

• Distribution: Happens on Arch and Fedora 38/39
• SteamVR version: Happens on 2.1.10, 2.1.9, 1.27.5
• Steam client version: 1701289036
• Opted into Steam client beta?: No
• Graphics driver version: Mesa 23.2.1-arch1.2
• Gist for SteamVR System Information: https://gist.github.com/issacdowling/21d99f3e29dcd71430d4ec3a475c6d9b

Additional context I have tried different Linux distros, different USB ports (including switching between USB 2 and 3), different SteamVR versions, lowering the render resolution to make it as easy as possible to render, I attempted to use amdvlk since normally I use radv, I tried the regular Linux kernel, linux-zen on Arch, and Linux-lqx on Fedora, and nothing helped with either headset. Tracking is 100% fine on Windows though.

The issue, though noticeable when looking side-to-side or just barely when standing still, has been most obvious when playing Beat Saber, as it seems like the tracking of my head shaking is either more extreme or delayed. I can't perfectly diagnose what is making it feel so bad, but that's my best hypothesis.

Note: Commenters who are also experiencing this issue are encouraged to include the "System Information" section in their replies.

[JohnTator]

Same issue with the same headsets and drivers. Using Linux Mint 21.2 Kernel version 6.5.0 graphics driver: nvidia-driver-535

happens on any version of Steam VR. Issue doesn't happen when using an inside-out tracked headset via ALVR.

Headsets have no issues on Windows

I'd describe it as if the lighthouse tracking were running at 1/10th the accuracy. Constantly snapping to positions haphazardly rather than the smooth experience on windows.

[issacdowling]

I have to wonder if it's an IMU thing rather than the lighthouses, since the controllers appear fine to my eye (though I haven't looked that closely).

Either way, it's nice to hear that someone else is having this issue, since maybe Valve will be more interested in fixing it. To be clear, when you say the same headsets, you mean you've tried both a Vive and Vive Pro 2?

[JohnTator]

Either way, it's nice to hear that someone else is having this issue, since maybe Valve will be more interested in fixing it. To be clear, when you say the same headsets, you mean you've tried both a Vive and Vive Pro 2?

Yes, OG Vive and Vive Pro 2 with the mentioned unofficial Linux driver for VP2. And yeah I forgot to mention it but my controllers seem to track fine for me too (Index Controllers), just a headset issue.

[dusanpol]

I have the same issue, headset tracking/render delay is inconsistent, it's either perfect, slowly increasing delay or snaps back to perfect, just as @JohnTator describes. Controller tracking looks fine.

• Linux Mint 21.2 (Ubuntu 22.04 based)
• Kernel 6.6.11-1-liquorix-amd64
• mesa 23.3.3~steamvr1
• SteamVR version: 2.2.3
• Steam client version: 1702079146
• betas: none
• AMD 5800X3D, AMD 7900 XTX

System report gist: https://gist.github.com/dusanpol/f6404c415c92f211255c6806f562dbbf

[issacdowling]

EDIT: Was just messing with vsync_to_photons_increment in the debug menu. I think this is a latency issue and my previous assumptions were wrong just due to seeing the slight movements of my head out of sync, making it feel like random shakiness. As described by @dusanpol, latency does seem to change, as I can use the debug menu to set a value that feels perfect, and then have it feel wrong at other times. Could be related to these Reddit discussions where I found the (nearly, but not properly working (solution)? https://www.reddit.com/r/SteamVR/comments/118vlrl/fix_for_rtx_4090_and_vr_tracking_input_latency_lag/

OLD TEXT: Maybe we're describing different issues. You say it snaps to being perfect? @JohnTator described it well when they said it seems as if tracking is less accurate (though I guess here, precision would be the issue, explaining the snapping to positions), and for me that's constant, and I imagine it's the same for them if we're dealing with the same root cause. I experience snapping, but positionally, not snapping to a lower latency.

@JohnTator Is it also the case for you, like me, that it never fixes itself or snaps to being better, it just stays bad?

Despite that, it's at least good to see someone with a different headset mentioning something seemingly similar (the gist says an Index), as it further rules out anything headset/vendor specific

[issacdowling]

Will change the title of the issue according to my new findings mentioned in the above edit. I don't think this is a duplicate of #21 though, as they mention controller issues too, which I don't perceive

[dusanpol]

I have new observations and a possible workaround.

• the delay gets fixed on a performance drop / framedrop. For example: loading next level in Walkabout Mini Golf / The Light Brigade, turning on SteamVR dashboard or just existing in modded Beat Saber 1.29
• delay gets smaller and less frequent with every kernel update. Currently on 6.7.1 and delay is present only 20% of the time
• setting high priority process for game helps

The possible workaround: Set highest priority and affinity only for physical cores (in my case: core 1-8 for 5800X3D) for vrserver, vrcompositor and the game process. I did it through System Monitor, but it can be automated by launch parameter for game and editing some scripts in SteamVR directory. This removed delay for 99% of time in my case.

EDIT: I did not find a way to edit scripts in SteamVR, so I just wrote a small script I run after I start SteamVR:

#!/bin/bash

# run as sudo
[ "$UID" -eq 0 ] || exec sudo "$0" "$@"

VRS_ID=`pidof vrserver`
VRC_ID=`pidof vrcompositor`
renice -n -20 -p $VRS_ID
renice -n -20 -p $VRC_ID
taskset -cp 0,1,2,3,4,5,6,7 $VRS_ID
taskset -cp 0,1,2,3,4,5,6,7 $VRC_ID

[Skyliner-369]

this issue exists on the Valve Index, though, is getting better with kernel updates here too.

system: Distro: Arch CPU: threadripper 1920x GPU: 7900xtx Sysmem: 64GiB Steamvr version: open beta of 4/14/24 more sysinfo available upon request

[terpyderp]

I have this issue too! :(

I've tried setting the process priority and affinity of the vrserver and vrcompositor like dusanpol mentioned, but I could only find vrcompositor, not vrserver, and it didn't seem to help anyway.

Distro: Kubuntu 24.04 Kernal Version: 6.8.0-31-generic (64-bit) Graphics Platform: X11

Processors: 12 × AMD Ryzen 5 5600X 6-Core Processor Memory: 15.5 GiB of RAM Graphics Processor: NVIDIA GeForce RTX 3060/PCIe/SSE2

VR Headset: Valve Index