Compatibility Report

• Name of the game with compatibility issues: ARC Raiders
• Steam AppID of the game: 1808500

System Information

• GPU: AMD Radeon RX Vega 56 (Vega 10, 1002:687f, 8 GB HBM2)
• Video driver version: Mesa 26.2.5 (RADV), Vulkan 1.4.354
• Kernel version: 7.2.11-zen1-1-zen
• Link to full system information report as Gist: https://gist.github.com/archaic-cv-01/36a6f2c6486c023793bc7ccc1a687493
• Proton version: Proton Experimental (bleeding-edge),
  experimental-bleeding-edge-11.0-456668-20261025-p5b1cb2-w7b3cea-dcbd220-vef9a02-x86_64
• Other: Arch Linux, XFCE (Xfwm4), X11; Ryzen 7 5700X (PBO: +200 MHz boost
  override, Curve Optimizer -30), 32 GB RAM

I confirm:

• [ ] that I haven't found an existing compatibility report for this game.
  (Not ticked: this is a follow-up to the existing report in this thread.)
• [x] that I have checked whether there are updates for my system available.

Symptoms

With default launch options (only PROTON_LOG=1 %command%) the game freezes
during its in-game shader compilation: the progress stops at 95-99%. The window
stays up and the game's audio keeps playing, but nothing moves and CPU usage
drops. The game does not crash. The freeze lasts at least a minute (the log
shows several 60 s loader_section timeouts); I close the game manually.

In the attached log, right before the freeze:
err:vkd3d-proton:d3d12_device_validate_shader_meta: Required WaveSize range [32, 32], but supported range is [64, 64].
Afterwards 8 other threads time out on ntdll's loader_section, all "blocked
by 05b4" - the same thread that logged the WaveSize error. An earlier capture
(Mesa 26.2.4, kernel 7.2.9, with a GPU undervolt I have since removed) shows the
same pattern: the thread that logs the error (0570) blocks 5 others.
Vega 10 only supports wave64, so I suspect the rejected shader leaves a
pipeline that is never created, but that is my interpretation, not confirmed.

Other notes:

• No amdgpu GPU reset, ring timeout or page fault in the kernel log (checked on
  the earlier capture).
• The same machine runs the game in DX12 without problems on Windows (AMD
  Adrenalin 26.5.2).
• %command% -dx12 gives the same result as the default launch.
  %command% -dx11 works without problems.
• Switching between Proton versions did not help (I did not keep the exact
  versions). Disabling the Steam shader cache and the compositor did not help
  either.

Workaround:

• VKD3D_SHADER_MODEL=6_5 %command% -NOTEXTURESTREAMING -useallavailablecores
  starts the game with no hang and no shader compilation step. Since -dx11
  alone also works, it most likely makes the game fall back to its DX11
  renderer (DXVK). Adding -dx12 to it makes the game say the GPU does not
  support DX12, so its DX12 path seems to require Shader Model 6.6.

Reproduction

1. Launch with PROTON_LOG=1 %command%, Proton Experimental (bleeding-edge).
2. Wait for the in-game shader compilation; it freezes at 95-99%.
3. Close the game and attach steam-1808500.log (gzip).

(English is not my first language; this text was prepared with AI translation
help.)

arc-1808500-20261025-200406.log.gz