Expected behavior

No static/corruption blocks in the compositor output, matching the artifact-free behavior on Windows with the same hardware and HMD.

Description

Intermittent rectangular blocks of static/visual corruption appear in the compositor output on the Bigscreen Beyond 2e. The artifacts appear as solid blocks of noise/static, not flickering or tearing. They vary in size and appear most frequently near the bottom-center of the field of view.

The same hardware (identical PC, same HMD, same USB/DP cables and ports) produces zero artifacts when booted into Windows with SteamVR. The issue is Linux-only.

Reproduction

• Artifacts appear during normal head movement in any SteamVR application (tested in VRChat and SteamVR environment).
• They are triggered by specific visual elements entering the field of view — not purely random.
• Frequency: multiple times per minute during active use. Too frequent to ignore.
• Location: predominantly bottom-center of vision, but can appear on either or both eyes.
• Size: varies from small patches to large rectangular blocks.

Suspected cause

The distortion correction shader in the SteamVR Linux Vulkan compositor. Evidence:

1. Artifacts are triggered by specific visual content entering the distortion-corrected region, especially near the edges/bottom of the lens.
2. The BSB 2e uses DISTORT_POLY3 lens distortion with coefficients [0.2302, 0.0977, 0.0830] and grow_for_undistort: 0.6 — a relatively aggressive undistort factor.
3. The same compositor already has known stereo rendering bugs on Linux (issues #732, #633) that required workarounds via enableLinuxVulkanAsync.
4. Windows SteamVR compositor (D3D-based) with identical HMD firmware and display parameters has no artifacts.

Relevant steamvr.vrsettings

"steamvr" : {
   "enableHomeApp" : false,
   "enableLinuxVulkanAsync" : true,
   "preferredRefreshRate" : 90,
   "showAdvancedSettings" : true,
   "supersampleManualOverride" : true,
   "supersampleScale" : 1.3244
}

HMD display parameters (from firmware)

• Eye resolution: 1920x1920 per eye (DSC target at 90 Hz)
• Native panel: 2560x2560 per eye (used at 75 Hz without DSC)
• DSC: version 17, 4 slices, 8 bpp
• Layout: side-by-side (3840x1920 combined)
• Lens type: DISTORT_POLY3
• Grow for undistort: 0.6