1706934 - Window content breaks for good with X11 EGL after suspending KWin compositing

Status: RESOLVED DUPLICATE of bug 1712665

(Core :: Widget: Gtk, defect, P2)

Description

[walmartguy]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:89.0) Gecko/20100101 Firefox/89.0

Steps to reproduce:

Run Firefox with Webrender & EGL ( MOZ_X11_EGL=1 ) in a Plasma Xorg session with KWin compositing enabled.
Then start a fullscreen application that tells KWin to suspend its compositing (e.g. a game that does so).

Actual results:

When returning to the desktop with the Firefox window (alt + tab or closing the fullscreen application), the content of the Firefox window is completely wrecked. This does not just apply to the website content of the opened tab, but also the menu bar etc. of Firefox are broken for good. It is not able to recover, e.g. by refreshing a page via pressing F5, Firefox needs to be restarted completely in order to be usable again.

Expected results:

Ideally, it shouldn't lose any window content, or at least only the website content and should be able to recover after reloading the page (or by itself). This is the case with the GLX backend.

This might be a regression that started with 88 or 87, though I could be mistaken.

Comment 1

[Kalamaris23]

Regression started with Firefox 88 additional information is available at
https://www.reddit.com/r/archlinux/comments/mvhfvy/firefox_8801_with_vaapi_breaks_when_using_mpv/
https://bbs.archlinux.org/viewtopic.php?pid=1969575

Comment 2

[aedyrn]

Can confirm it happens to me on both arch and manjaro with both kwin and kwinft. Tried to replicate it on gnome but it seemed to work fine there, not sure if I just couldn't force gnome to disable compositing (tried forcing mpv and uniengine superposition) or it's a specific kwin-firefox problem.

Comment 3

[Martin Stránský [:stransky] (ni? me)]

Do you mind to report it at KDE bugtracker? (https://bugs.kde.org/) I don't think we have manpower to work on it.

Comment 4

[walmartguy]

I can drop a report. Though I'm afraid it won't contribute to a solution, as I think this is due to the Firefox X11 implementation not taking measures to maintain its window content integrity beyond X11 compositors toggling on/off. I haven't checked, but I'd assume this also happens when using Picom compositor and closing it while Firefox EGL is running. It doesn't happen on Gnome, as Mutter compositing is always active and it supports fullscreen unredirect, which KWin unfortunately doesn't (and probably never will on Xorg).

Comment 6

[Mufeed Ali]

Report on KDE tracker: https://bugs.kde.org/show_bug.cgi?id=440154 .
It was closed as an issue with Firefox.