When using the Automatic VSync strategy of KWin, it causes tearing here on my i915. When I use "Reuse screen contents" it's fine. Automatic → Tearing Only When Cheap → Tearing Full Repaint → Ok Reuse screen contents → Ok Reproducible: Always
Created attachment 80772 [details] Supportinformation
Don't use "reuse screen content", it's extremely expensive on MESA drivers! Pplease restart kwin after ever selecting "reuse screen contents" - expensive path in the driver won't be left otherwise. Automatic will choose "Only when cheap" and that would only cover (near) full screen repaints. -> Do you get tearing with automatic setting and (near) fullscreen updates, eg. fullscreen video playback?
> Do you get tearing with automatic setting and (near) fullscreen updates, eg. fullscreen video playback? No I don't but I get it when moving windows which annoys quite a bit. So what else should I choose? Full repaint?
> > Do you get tearing with automatic setting and (near) fullscreen updates, > > eg. fullscreen video playback? > No I don't but I get it when moving windows which annoys quite a bit. > So what else should I choose? Full repaint? Full repaint is quite heavy (I can hear my CPU fan when using it), but is absolutely tear free. With automatic I have tearing when scrolling in Firefox, for example.
Maximized firefox? Also maximized <otherbrowser>? (I recall a picture on a bug that indicated scrolling firefox to cause partial damage events on different frames) @Kai Always cheap vsyc will be available with buffer_age support, but not in 4.11. https://git.reviewboard.kde.org/r/110642/
> Maximized firefox? no, I'm normally not using maximized browsers. Will try to observe > > Also maximized <otherbrowser>? > (I recall a picture on a bug that indicated scrolling firefox to cause > partial damage events on different frames) hmm, I will try to use some other browsers and observe
Could no longer reproduce that horizontal tear line in the upper third of the browser window when scrolling
(In reply to comment #6) > no, I'm normally not using maximized browsers. Will try to observe The minimum ratio is at 74.8% of the screen (16:9 on a 4:3 screen) resp. 49% (2.55:1 on 5:4) for an opaque fullscreen window (videoplayer, worst thinkable case) If the updated region is smaller, you'll get tearing unless you explicitly chose to always have fullscreen repaints. That's expected for the present strategies.
*** This bug has been marked as a duplicate of bug 319995 ***