Strange game behavior on dual monitors on Linux

[vladislav805]

After some point (approx 18 October 2022), Portal 2 on Linux began to display the game strangely. Pictures/backgrounds are ok, but interactive elements (menu, game itself) seem to be flattened/compressed.

Example

I have two displays with different resolutions: 2560x1440 (primary), 1920x1080 (secondary). Game is launched on primary display. But in the game settings in the "video" section, as the native size (and the default size) me offered 4480x1440 (That is, the maximum area of two displays - width=2560+1920=4480, height=max(1440, 1920)=1440)

Screenshot

Also, the game itself perceives the cursor as if it is more to the right than it actually is relative to the monitor. E.g, if I need to click on the "Back" button in the game settings, then I need to point and click on the place that is slightly to the right of the button (below I uploaded two videos with an example of the interface).

If I disable the second display (for example, in the OS settings), then the native size is normal (as primary display, 2560x1440) and the image in the game is also normal. If I run game "in window" or "windowed (without borders)" then image in the game is normal, but low fps (as expected).

If i run game in "windowed (without borders)" with "native" resolution, it takes two displays, but image is normal:

Screenshot

What is in the red frame - I do not see, on the right is the second display, which is smaller than the left one.

In the same computer in Windows 10 problem is not reproduced. Verifying game files, reinstall game/Steam is not solve the problem. Set launch options -w 2560 -h 1440 also is not solve the problem.

Portal 1 and Counter-Strike: Global Offensive don't have same problem.

There are two videos with the reproduction of the problem. 2022-12-19_22-45-35.webm 2022-12-19_22-48-01.webm

In what direction can you think how to fix it or what could be the problem? Thank you in advance.

OS: Arch Linux (core 6.0.12-arch1-1) DE: Xfce 4.16 GPU: Nvidia GeForce RTX 3060 CPU: AMD Ryzen 5 3500x

[OvercastWarmth]

I can confirm this issue using Pop!_OS 22.04 LTS using an NVIDIA RTX 3050, not sure if window manager affects it but I'm using gnome as of current, and I might check other WMs to see if I can reproduce the problem.

[Mars7x]

This can be fixed by using Vulkan instead of OpenGL. Add -vulkan to Portal 2's launch options.

[vladislav805]

Thank you, with -vulkan everything works as it should.

However, isn't the above described behavior on OpenGL a bug? Until I don't close the issue.

[OvercastWarmth]

Can confirm that vulkan fixed it, thanks so much

[twilson271828]

Adding -vulkan also fixed it for me.