[PERF] Jittering on Arch

[rs189]

Describe the bug When running SteamVR even in the base empty environment (Not SteamVR Home), I experience jittering when moving the head, especially so if moving fast.

To Reproduce Steps to reproduce the behavior:

1. Open SteamVR
2. (Optional) Open VRChat

Expected behavior Smooth VR experience as is on Windows.

System Information (please complete the following information):

• Distribution: Arch (EndeavourOS)
• SteamVR version: 2.7.4
• Steam client version: 1726604483
• Opted into Steam client beta?: No
• Graphics driver version: 560.35.03
• Gist for SteamVR System Information: https://gist.github.com/rs189/62a461fecc5e3eb4d93ce116533f1bb5

Performance Data (optional, but very helpful):

• CPU: i7-10700K
• GPU: NVIDIA RTX 2070
• Gist for perf top: [See instructions]
• Link to gpuvis trace: [See instructions]

Screenshots

Additional context I am NOT looking to use Monado personally even though it doesn't jitter.

I am using Gnome 47 with Wayland as it just added DRM support (Prior versions of Gnome did not support DRM on Wayland) I experience the same problem under X11 too.

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

[Taiko2k]

For me 2.7.4 is complete chaos, just look at this wall of pink I got:

For 2.8.4-beta for me its random depending on what mood SteamVR is in when you start it, all I did between these two screenshots is restart SteamVR:

Of course the photon latency is still all over the place, so SteamVR is still unusable for me even when it decides to give green.

[digivation]

I am on Arch (6.9.7), and have Nvidia driver 555.58. I am using Plasma on Wayland. I'm running on an Asus G14 (2023 - GA402) with RTX 4060 Laptop GPU. I have SteamVR beta 2.8.4. I am using a Valve Index.

For me, adding nvidia NVreg_EnableGpuFirmware=0 to modprobe.d/nvidia.conf did the most to resolve this issue, and the wall of pink is now gone, with only occasional spikes (still hunting those down), but much more usable.

My /etc/modprobe.d/nvidia.conf file contains the following (note: NVreg_PreserveVideoMemoryAllocations is for an unrelated issue and you may not need it):

options nvidia_drm modeset=1
options nvidia_drm fbdev=1
options nvidia NVreg_PreserveVideoMemoryAllocations=1
options nvidia NVreg_EnableGpuFirmware=0

After updating, run sudo mkinitcpio -P to regenerate initrd with updated parameters.

Additionally, I have the following kernel parameters set (unsure if these are needed in addition to the above):

nvidia-drm.modeset=1 nvidia-drm.fbdev=1

These are probably duplicates of the modprobe.d but I haven't removed them yet.

I also have the following SteamVR launch options set, unsure if this made a difference (haven't experimented with this yet): __GL_MaxFramesAllowed=0 %command%

[SpookySkeletons]

@digivation We had our LVRA members test these tweaks, its not a silver bullet for stutter. Monado is still the only way to get a stutter free experience.

It does improve somewhat for nvidia users and modesetting + wayland should be used anyway on nvidia.