5.8 Freezing on UI interaction

General Issues and Bug Reporting (Unreal Engine)
1

Summary

Following issues not present in 5.7.4: Upon load, buttons or dropdown menus cause complete freeze and sometimes crash. For some reason i can load the new project window and mouse around, but selecting a dropdown or hitting the create button will freeze 100%. Have also tried loading with these flags SDL_VIDEODRIVER=x11 ./UnrealEditor -dx11. This was repeated with a ubuntu 22.03 docker, but this version is outdated and doesnt support newer radeon cards, so UE 5.8 wont load.

System:
Ubuntu 24.04
XFCE X11
Ryzen 9 5900xt
Radeon R9700 (RDNA 4)
64GB DDR4
AM4 socket

What Type of Bug are you experiencing?

Editor

Steps to Reproduce

Run 5.8 on an ubuntu X11 DE. If it works try it with a radeon card (rdna 4 with latest mesa driver).

Expected Result

The UI of UE can be navigated without freezing.

Observed Result

The UI of UE freezes.

Affects Versions

5.8

Platform(s)

Linux

Vulkan RHI submits batches that wait on binary semaphores before the corresponding signal operations are submitted (violates VUID-vkQueueSubmit-pWaitSemaphores-03238); deadlocks on Mesa/RADV Linux
2

Love how the release notes list linux support when it not even working on a “supported” distro like Ubuntu

1 Like
3

Also same issue sadly.

4

Another bug report I saw.. Expected result “Work” pfft..
Sad but that’s basically the crux of it.

5

I upgraded from a source build of 5.7 release to 5.8 release and the editor freezes shortly after launch.

By default, the editor loads as a giant black screen with white lines.

If you run with the following Env vars:


SDL_VIDEODRIVER=x11
RADV_DEBUG=hang

and the following renderer settings:

[/Script/Engine.RendererSettings]
r.RayTracing=False
r.DynamicGlobalIlluminationMethod=0
r.Shadow.Virtual.Enable=0
r.ReflectionMethod=0

The editor will launch for me but freeze up after a few seconds.

Quite frustrating.

6

Your GPUVM fault matches a RADV bug I reported with a fix open:

vkGetDescriptorSetLayoutSizeEXT returns 0 for mutable descriptor layouts containing acceleration structures, so UE 5.8’s bindless renderer creates a zero-sized descriptor buffer and the GPU faults on first access:

- Issue

- Fix

Heads-up: with that fixed you’ll likely hit a second Mesa bug — the editor freezing after ~a minute (deadlock in the common Vulkan runtime, triggered by UE 5.8’s multi-queue submission):

With both MRs applied locally, UE 5.8 runs correctly here on an RX 9070 XT. If you can test them on your 6900 XT, a confirmation comment on the MRs would be valuable (different GPU generation).