Dear beloved and much esteemed Maintainer, forcing webrender material acceleration used to work fine on my AMD hardware, but since latest update it creates large transparent blocks in webpages on scrolling, disables some elements ( like drop-down menus on https://www.debian.org/distrib/packages ), and renders UI element broken or very unresponsive (like the main pancakes menu). Disabling webrender material acceleration fixes the problems. So while the forced acceleration is not standard, it looks like a regression in that area from previous versions. I am running a Wayland session in Plasma KDE, the GPU is an AMD Radeon 7900XT. Thank you for your attention.
Hi, I have the exact problem described. How do you disable "webrender material acceleration" actually? I've tried turning off "Use hardware acceleration when available" under advanced preferences and also set gfx.webrender.software to true and restarted the browser but still have the issue. Thanks.
Hello, there are several settings involved, the "use recommended performance settings" and "use hardware acceleration when available" from the general settings page are a start. On Linux most of hardware acceleration is blacklisted anyway, so those settings won't do much. If you want more fine-grained options you need to open the "about:config" advanced settings page, then filter for "webrender". "gfx.webrender.all" and "gfx.webrender.compositor" will turn hardware acceleration IF your hardware and software (mesa) are not blacklisted. If you want to enable hardware acceleration anyway, to test it at your own risk, then flip "gfx.webrender.compositor.force-enabled" to true, and "gfx.webrender.software" to false. Conversely if you want to force software rendering turn everything to false, and "gfx.webrender.software" to true. You need to restart Firefox after making any change. I am only talking about webrender here, not to be confused with webgl acceleration which can be enabled only on Firefox development version AFAIK, and is very unstable. Hope it helps.
I can confirm that gfx.webrender.compositor.force-enabled was the offending option and was set to true. This as well as the other mentioned options are now default. I don't remember changing it but it must have worked ok in previous versions. Thanks!
I tested an upstream version of Firefox 137 and there the default is to disable hardware acceleration for webrender on Linux with my hardware. Despite the general "use default performance settings" being ticked, or even when ticking manually "use hardware acceleration when available" the result doesn't change, no hw acceleration is enforced, and the described bugs don't manifest. When manually enabling through the "about:config" page the result is the same, the bugs appear. So the regression is either in upstream Firefox, or in some other library shipped in Debian Unstable (Mesa comes to mind). I humbly admit that I am not familiar with Firefox development and can't make a guess as to what broke. Firefox change-log doesn't strike me as obviously suspicious in that area.