Comment 0 for bug 1930982

Firefox 89 enabled the Webrender framework by default. Unfortunately, the GFX drivers on a Pi 4 seem to be non-compliant in a way that breaks videos - specifically, there will be a lot of primary coloured artefacts in videos. My guess is that other Raspberry Pi's will also be affected, but I don't have the hardware available to test. Setting gfx.webrender.force-disabled to True fixes the issue, so it's fairly clear where it lies.

Mozilla doesn't seem to provide official builds for Raspberry Pi's (or Linux/Arm in general), so I think this is an issue with these packages, rather than upstream. The quick solution would to just set gfx.webrender.force-disabled to True for the Pi-platforms and be done with it, but there may be better solutions I don't know about.

Additioal info:
Ubuntu release: 21.04
Firefox package: firefox/hirsute-security,hirsute-updates,now 89.0+build2-0ubuntu0.21.04.1 arm64
Steps to reproduce: Play a video on Youtube, watch the coloured blocks appear. Then set gfx.webrender.force-disabled to True and restart to verify the fix.