BUG] Steam Link VR: persistent right-eye ghosting during head movement on Quest 3S

[poggieboii78-arch]

vrserver.txt
vrcompositor.txt

Describe the bug

When using Steam Link VR (driver_vrlink) with a Meta Quest 3S on Linux, the right eye shows persistent double imaging / ghosting whenever I rotate or move my head. The effect continues for the duration of head movement and stops immediately when my head becomes still. The left eye remains clear.

This is reproducible across SteamVR games and is not present in the Quest's native applications.

I am currently seeing this on SteamVR Beta 2.17.8; it was also present on 2.17.7 stable.

Steps to reproduce

1. Run SteamVR on a Linux PC with the Quest 3S connected through Steam Link VR (driver_vrlink).
2. Use a wired Ethernet connection from the PC to the LAN/router.
3. Connect the Quest 3S using Steam Link.
4. Launch any SteamVR game.
5. Move/rotate your head at a normal speed.
6. Observe the right eye: objects produce a persistent double/ghosted image while the head is moving.
7. Stop moving your head; the ghosting disappears immediately.

Expected behavior

Both eyes should display a single, stable image during head movement, with correct stereo timing/alignment.

Troubleshooting / observations

I have tried to isolate this from several other possible causes:

• Headset/lenses/IPD: The issue does not occur in Quest Home or other native Quest applications. It only occurs through SteamVR/Steam Link.
• Refresh rate / rendering load: Changing the Quest refresh rate between 72, 80, 90, and 120 Hz did not resolve it. Lowering render resolution/supersampling also had no effect.
• Async reprojection: vrcompositor.txt reports Async support disabled by user setting or a direct mode driver, so async reprojection is not active in this configuration.
• Motion Smoothing: SteamVR reports Motion Smoothing as Not Supported for driver_vrlink.
• Network instability: I previously found a separate problem caused by a stale tailscale0 interface. It produced repeated SVLDataLinkUber: Received event indicating network change events and forced stream resets (HandleUnrecoverableError). Removing the stale interface eliminated those resets, but the right-eye ghosting remained unchanged, so the two issues appear independent.
• vrcompositor crashes: During testing I also observed two rare vrcompositor segfaults in dmesg. They occurred only twice during roughly 15 minutes of testing and do not match the continuous, head-motion-dependent ghosting. These may be related to the 2.17.8 fix for invalid textures, but the ghosting persists independently.
• SteamVR settings: Resetting steamvr.vrsettings to defaults did not change the behavior.
• Allow Reprojection: Disabling the Performance setting did not change the behavior.

Suspected cause

I do not know the exact cause, but the combination of:

• only one eye being affected,
• the artifact appearing specifically during head motion,
• the artifact disappearing immediately when motion stops, and
• the artifact persisting despite changing refresh rate, resolution, and network conditions

makes me suspect a stereo frame timing / pose sampling / reprojection or presentation synchronization problem somewhere in the Steam Link VR path.

I am deliberately not assuming that this is specifically async reprojection, since async is disabled in my configuration. It could instead be related to how the two eye images are selected, timestamped, warped, or presented by the compositor/vrlink path.

There is some precedent for motion-dependent double vision in the Linux SteamVR tracker. Issue #344 reports double vision while rotating the head, and issue #917 describes head-motion-related double images and stereo/frame timing problems in a different headset/reprojection configuration. These reports are not identical to this bug, but may be useful for comparison.

System Information

• Distro: CachyOS x86_64
• Kernel: 7.2.0-1-cachyos
• Desktop: KDE Plasma / KWin on Wayland
• CPU: AMD Ryzen 7 5800XT (8-core)
• GPU: AMD Radeon RX 7600 (Navi 33), RADV
• Headset: Meta Quest 3S
• Connection: Steam Link VR / driver_vrlink, PC connected over wired Ethernet
• SteamVR: 2.17.8 (Release Candidate beta); also reproduced on 2.17.7 stable
• Steam Link client: qvlclient;panther;2.0.22.2145
• LAN: 192.168.1.x

Additional information

I can provide fresh vrserver.txt / vrcompositor.txt logs, SteamVR system information, or reproduce the issue with specific debugging/settings changes if needed.

A useful diagnostic would be determining whether the right-eye artifact is already present in the compositor's eye textures/frame timing, or whether it is introduced later in the vrlink/streaming/presentation path.

[Packetdancer]

If you can reproduce this easily, can you actually change SteamVR's launch parameters to:

VRLINK_DUMP_BITSTREAM=1 %command%

...and then connect again, and cause the ghosting? Then disconnect (and unset that variable so you aren't dumping to disk on future runs).

You'll find a /tmp/vrlink_bitstream_<timestamp>.h265 file which contains the raw encoded video that was sent to the headset. If you can then give that file to us via dropbox or Google Drive or whatever else, that'll help see whether the ghosting is something on the encoding side (e.g. on the host), or a problem on the Quest side.

[poggieboii78-arch]

If you can reproduce this easily, can you actually change SteamVR's launch parameters to:

VRLINK_DUMP_BITSTREAM=1 %command%

...and then connect again, and cause the ghosting? Then disconnect (and unset that variable so you aren't dumping to disk on future runs).

You'll find a /tmp/vrlink_bitstream_<timestamp>.h265 file which contains the raw encoded video that was sent to the headset. If you can then give that file to us via dropbox or Google Drive or whatever else, that'll help see whether the ghosting is something on the encoding side (e.g. on the host), or a problem on the Quest side.

https://drive.google.com/file/d/1OwxL_XL85FXPyqyMSNZvOPGPSfpmZmlx/view?usp=sharing