So after a bit of discussion, here's my thoughts/conclusion: * it's gonna take us a bit to work out exactly what's going wrong, which is annoying for wr mac dogfooders (on 2015+ macs) * putting gpu migration behind a pref here should make the correctness issues go away: https://searchfox.org/mozilla-central/source/widget/cocoa/nsChildView.mm#1711 * gpu migration is "just" a perf/power optimization, and we only "need" to disable it with wr, so that seems fine to do short-term So I think I'm going to add a gfx.compositor.gpu-migration flag, with one of two designs: * tristate of "force-disable" (0), "force-enable" (2), "use where it works" (1, the default) * just a "force-enable" boolean to opt into using it on wr (not sure which is better, also not sure if I would make it a live pref) Either way the default would be for gpu migration to be off with WR and on without (which we would change as the impl gets better or worse).
Bug 1599862 Comment 6 Edit History
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So after a bit of discussion, here's my thoughts/conclusion: * it's gonna take us a bit to work out exactly what's going wrong, which is annoying for wr mac dogfooders (on 2015+ macs) * putting gpu migration behind a pref here should make the correctness issues go away: https://searchfox.org/mozilla-central/source/widget/cocoa/nsChildView.mm#1711 * gpu migration is "just" a perf/power optimization, and we only "need" to disable it with wr, so that seems fine to do short-term * also even if it's disabled, macos seems to aggressively want to be mac on integrated graphics, so pref issues may go away quickly in some cases (e.g. the discrete-demanding page/application is closed) So I think I'm going to add a gfx.compositor.gpu-migration flag, with one of two designs: * tristate of "force-disable" (0), "force-enable" (2), "use where it works" (1, the default) * just a "force-enable" boolean to opt into using it on wr (not sure which is better, also not sure if I would make it a live pref) Either way the default would be for gpu migration to be off with WR and on without (which we would change as the impl gets better or worse).