Firefox 81 on Linux and hardware acceleration supposedly on by default
Even though Firefox 80 and 81 release notes doesn't say anything, many websites stated that hardware acceleration on Linux X11 was introduced in Firefox 80, but disabled by default, while it was enabled by default in Firefox 81.
This is what I see in my about:config and, honestly, it's definitely unclear (using Firefox 81, of course):
HW_COMPOSITING available by default / blocked by env: Acceleration blocked by platform OPENGL_COMPOSITING unavailable by default: Hardware compositing is disabled WEBRENDER opt-in by default: WebRender is an opt-in feature WEBRENDER_QUALIFIED available by default / denied by env: Not on allowlist WEBRENDER_COMPOSITOR disabled by default: Disabled by default WEBRENDER_ANGLE opt-in by default: WebRender ANGLE is an opt-in feature WEBRENDER_DCOMP_PRESENT opt-in by default: WebRender DirectComposition is an opt-in feature OMTP available by default WEBGPU disabled by default: Disabled by default / blocked by runtime: WebGPU can only be enabled in nightly
What should I understand from this? Sounds like it's all DISABLED on my system (Linux Mint 18.3, based on Ubuntu 16.04, Intel Haswell integrated GPU). Why!?
Also, what is the right way to enable some hardware acceleration now? OpenGL, WebRender, FFMPEG/VAAPI... it's a real mess. Until some versions ago, I simply used layers.acceleration.force-enabled=true and this enabled OpenGL hardware compositing. But what is the right way to do it now?
Why can't Firefox developers simply add an option in Preferences to enable or disable hardware acceleration!? The only current option "use hardware acceleration when available" doesn't mean anything. I have been using OpenGL hardware compositing with layers.acceleration.force-enabled=true for years with no issues at all, yet Firefox always decided that I should not use any kind of hardware acceleration on my system... Quite disappointing.