Does the x11-bypass-compositor option have a sane default?

[wpdevelopment11]

I am on Kubuntu 24.04 (Xorg). I have two screens. When I open mpv in fullscreen mode on a secondary
screen I see visual artifacts around window borders on a primary screen, and when I move windows I see tearing.
In other words, desktop becomes unusable once I open mpv in fullscreen mode on a secondary screen.

I am not experienced Linux Desktop user and took me quite some time to find out the root cause.
I tried other players based on mpv: Haruna, SMPlayer. They worked just fine.
This was not related to my config, mpv --no-config produced the same results. I tried two mpv versions: mpv 0.37.0 installed from apt repo, and 0.40.0 installed using snap. Both was unusable in fullscreen mode.

Then I realized that is something related to KWin and window decoration, and was able to find solution on the web.

Adding this to mpv.conf solved my problem:

x11-bypass-compositor=no

I think that option that can potentially break desktop should not be enabled by default.

Other poor souls already reported problems with x11-bypass-compositor option on KDE:

• Black screen, flickering, persistent Latte-dock issues with fullscreen mpv #9582
• https://www.reddit.com/r/kde/comments/oo8069/kde_conflicts_with_mpv_fullscreen/
• https://www.reddit.com/r/kde/comments/6yk4zv/is_it_just_me_or_kwin_crashes_if_mpv_enters/

[Dudemanguy]

There is no reason to composite a fullscreen application. What you're seeing is just an xorg limitation since compositing is not per screen but global. Instead of using compositing to eliminate tearing, you can try the tear free driver option. I don't think that should have the problem you mentioned regarding multiple screens, but I haven't tried it.

[wpdevelopment11]

Thanks for explanation.