MangoHud breaks Godot Vulkan renderer unless single-window mode is used

[Calinou]

This is a report of an issue that has seen multiple confirmations on various MangoHud versions, on multiple Linux distributions, and on both NVIDIA and AMD (amdvlk and radeon).

MangoHud breaks Godot Vulkan renderer unless single-window mode is used. In other words, any window spawned on top of the main window (such as dialogs) will freeze and never render anything. It can also cause the GPU to hang for 10+ seconds, making the whole screen freeze for a bit (including the mouse cursor).

Godot 3.x (which uses OpenGL 3.3 or OpenGL 2.1) is not affected by this issue, but it does not support multiple windows anyway.

I might try to test old Godot versions to see if the problem comes from our end, but I'm reporting it here just in case it's something that can be fixed in MangoHud.

PS: Godot 4.0alpha4 binaries (which use Vulkan) can be downloaded here. Single-window mode can be enforced using the --single-window command line argument, but keep in mind it does not carry over from the project manager to the editor.

[flightlessmango]

What MangoHud version are you testing with here?

[Calinou]

What MangoHud version are you testing with here?

mangohud doesn't appear to have a --version CLI argument, but it's an old build from May 2021. However, other people in the issue report were using more recent versions. Tagging them so they can reply here:

@Lasuch69, @afk-mario @CheesecakeCG Which MangoHud version are you using?

[CheesecakeCG]

Which MangoHud version are you using?

0.6.6 from the AUR

[afk-mario]

What MangoHud version are you testing with here?

mangohud doesn't appear to have a --version CLI argument, but it's an old build from May 2021. However, other people in the issue report were using more recent versions. Tagging them so they can reply here:

@Lasuch69, @afk-mario @CheesecakeCG Which MangoHud version are you using?

0.6.6.1-1 from the AUR

[jackun]

It gets stuck in vkQueueSubmit waiting in fragment shader for present semaphore(s) to trigger.
Seems to work with ANV on Intel i7-3720QM though.