Wayland: Minimize surface commits and limit them to the main thread #93684
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Before of this patch, as explained in the usual commented-wall-of-text-longer-than-the-actual-patch-itself™, due to the multithreaded nature of the Wayland thread, it was possible to commit a surface while the renderer was doing stuff, which was _very_ wrong. Initially the consequences of such a sin weren't obvious but, now that explicit synchronization is becoming more and more common, we can't commit a buffer randomly without basically guaranteeing a nasty, nasty crash (and we should have avoided commits altogether in the first place to ensure atomic surface updates). We now only trigger a commit _in the main thread_ when low processor usage mode is on _and_ if we know that we won't be rendering anything as, due to its intermittent nature, it makes "legacy" (pre xdg_wm_base v6) frame callback based suspension quite annoying.
akien-mga
approved these changes
Jun 28, 2024
akien-mga
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This was referenced Jul 15, 2024
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Fixes #93669.
Before of this patch, as explained in the usual
commented-wall-of-text-longer-than-the-actual-patch-itself™, due to the multithreaded nature of the Wayland thread, it was possible to commit a surface while the renderer was doing stuff, which was very wrong.
Initially the consequences of such a sin weren't obvious but, now that explicit synchronization is becoming more and more common, we can't commit a buffer randomly without basically guaranteeing a nasty, nasty crash (and we should have avoided commits altogether in the first place to ensure atomic surface updates).
We now only trigger a commit in the main thread when low processor usage mode is on and if we know that we won't be rendering anything as, due to its intermittent nature, it makes "legacy" (pre xdg_wm_base v6) frame callback based suspension quite annoying.
For more information, please see #93669 (comment) .