Hello, we got an interesting issue reported with BeamNG’s Vulkan renderer on native Wayland (not XWayland), best described as “frames from the past occasionally flicker in the viewport”. Here’s a video: https://media-cdn.beamng.com/atW3q50z6f5P8nVZ4gaWh8hI70KmmddL?start=0
We’re trying to find a bug in the engine presentation code, but so far we don’t see a Vulkan spec violation that could cause this behavior, our frames are submitted in order.
Facts:
- only NVIDIA users are affected
- happens only on Wayland, not X11
- tested on Ubuntu 26 with both 595 and 610 drivers with both Mutter and KWin, we get reports from all sorts of Linux setups. Tested also with 610-open.
- issue is visible only if application frame rate is lower than monitor refresh rate
- doesn’t matter whether fullscreen/window is used, presentation mode also doesn’t seem to matter, tested Fifo and Mailbox
- 3 swapchain images are used
I made a sample application (Vulkan + SDL3 + ImGui), it exhibits similar behavior to the BeamNG bug, hopefully stemming from the same root cause. Here is the source code, make sure to run it under Wayland:
wayland-stale-image.tar.gz (9.4 KB)
Here is the video from the sample application exhibiting the bug: https://media-cdn.beamng.com/xVhH2Rw1o1p6OEVTuFz0XkzdAKgejoDb?start=0
In the middle of the video you can see frame counter go 89 → 2 → 91 → 90 → 93, frame 2 was the previous frame using swapchain image 2 (img=2 in the app). For the sample application it seems that moving cursor out of the window and back triggers the bug more reliably.
Let me know if you need some more information.
nvidia-smi:
+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 610.43.02 KMD Version: 610.43.02 CUDA UMD Version: 13.3 |
+-----------------------------------------+------------------------+----------------------+
| GPU Name Persistence-M | Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap | Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|=========================================+========================+======================|
| 0 NVIDIA GeForce RTX 4090 On | 00000000:26:00.0 On | Off |
| 0% 48C P8 38W / 300W | 3177MiB / 24564MiB | 40% Default |
| | | N/A |
+-----------------------------------------+------------------------+----------------------+
The nvidia-bug-report.log.gz file gets stuck while uploading, but I can send it by e-mail if needed.