We want to start experimentally enabling Software WebRender for a reasonable portion of the Linux Nightly user population. These users should be ones who are currently on Basic layers because they are blocklisted from both WebRender and accelerated layers. Further, we want to limit this to users whose screen sizes are less than 4k (probably 1920x1200 and less).

The current gfx.webrender.software pref only works to force-enable it, whereas in this case we need a mechanism (possibly a new pref) that will only enable SW-WR if acceleration was not available in some form...

Bug 1674866 will add the infrastructure for this, and then we can add an allowlist rule in GfxInfo to enable this for the configurations we want to support.

Pretty sure this is an obsolete bug, we landed changes for the rollout somewhere else. Can we close this out Andrew?