[Linux, AMD] Aspect ratio for UI is detected incorrectly, if corrected FPS drops from >100 to 15

Kaydax

My display's resolution is 1280x1024, the game detects it as 1280x800. The UI is vertically stretched, but 3D rendering is at correct resolution. Settings screen displays correct resolution; if I hit Apply, the GUI straightens itself, but FPS drop dead. Symptoms continue on restart, and don't stop until I manually edit the config to assume incorrect resolution and stretch the gui.

Kaydax

Kaydax wrote: »

The UI is vertically stretched, but 3D rendering is at correct resolution

No, 3D is stretched too. I can't use resolutions higher than 1280x768 (1280x960, 1280x1024) no matter what desktop resolution I set. Whether other resolutions are playable sometimes changes depending on whether second display is connected. This is not a problem with my hardware, since the drop is very sharp (200 fps in 1280x768 vs 20 fps in 1280x960 in Tutorial Lobby). This is, probably, not a compositing issue — launching the game without a WM with 'exec steam' in .xinitrc doesn't work either.