Created attachment 130350 [details] system env All KDE software built from git master as of five minutes ago. Firefox flickers horribly on Wayland for me. The experience makes Firefox practically unusable. A video showing what it looks like can be found here: https://www.dropbox.com/s/4xbknleyvscmycn/video.zip?dl=0 (it's too large to upload) This happens with the XWayland version, or with GDK_BACKEND="wayland" set in the environment, or without that envar set at all, or when run from weston-terminal inside KWin.
Using Basic compositing mode in Firefox.
I don't see it running MOZ_ENABLE_WAYLAND=1.
There is no improvement whatsoever with MOZ_ENABLE_WAYLAND=1 set. :(
I can confirm this issue with Firefox running natively on Wayland and with web renderer disabled. Enabling web renderer fixes these glitches on my system.
So we seem have at least 2 FF settings witch influence - compositing mode and web renderer. With default settings the bug should arise.
Confirmed, the problem is completely resolved when manually enabling WebRender by setting gfx.webrender.all to true in Firefox's about:config window.
And naturally I immediately set mine to false to reproduce and debug it :) The situation is quite weird. We are getting alternate buffers from firefox that are of different sizes. Based purely on my logs, kwin is entirely in the right and firefox is sending us garbage data.
You're the hero we need but don't deserve. :)
So is it looks like FF problem? If so, should we report it there?
Yes and no. If Firefox sends garbage buffers, the window contents should only bounce. No visual artifacts like the ones in the first comment should be visible.