Comment 8 for bug 1886129

I agree it sounds like nouveau. That box has issues with the 5.13/5.15 kernel with GNOME, KDE with nouveau on occasion, and has for a few releases now (22.04, 21.10 & possible earlier).. but was always good with Lubuntu/Xubuntu (I really use it now only for install tests & have been thinking of switching out video card)

I booted Xubuntu 22.04 LTS on the box the bug report was made on
- hp dc7700 (c2d-e6320, 5gb, nvidia quadro nvs 290)

the external drive is no longer present, so I instead `apt install nfs-common` & mounted a NFS share for the random video files. Display setup was adjusted to match my setup (one screen above the other), then thunar navigated to various directories containing video files, and them dragged to an open parole player.

The parole player was adjusted (window size), dragged around, maximized, un-maximized, full-screen, normal, then another video file dragged to it. This was repeated many times with many different files (may not have been the same file type).

I did NOT re-create that issue.

ALTERNATE/DIFFERENT ISSUE:

I did have a case where a new video was started (mp4) in the existing player, the player was dragged to the other screen, then made to be full-screen; the controls went to the bottom of the screen, but the movie-picture did not increase in size; remaining the same identical size/shape as before the 'f' for full-screen was commanded (ie. picture remained small window size).

If I hit 'f' again to return it to normal size; it would return to normal, hit 'f' again and it properly went to full size (controls at bottom of screen and video-picture using all of screen size)... hitting 'f' repeatedly to return to window, then back to full-screen (not pressing 'f' quickly; giving it time to cope given this box is old/slow) & the issue of black-background, controls at the bottom but video-picture remaining window-size would re-occur every so often (3rd time, 5th time, 11th time, 12th time, .. On some occasions the small video-picture had the rest of the display black, other times the wallpaper & thunar window was still evident.

That however is a different issue.. and again maybe nouveau related so I'm going to ignore unless requested to file a new bug against it (where I'll try & re-create it & explore further, inc. on another box [hp 8200])