GNOME On Wayland Lands Improved Handling For Direct Scanout Support

Adding to the changes for GNOME 42 this spring is the Mutter Wayland compositor now taking into account sub-surfaces when determining direct scanout capabilities.

GNOME's Mutter already supports direct scanout for full-screen clients to reduce latency and resource use for games and other full-screen software by avoiding any extra screen copy of the screen contents and instead sending the application/game's contents directly to the output. Just earlier this week Mutter landed DMA-BUF feedback support for improving its direct scanout capabilities particularly for multi-GPU/hybrid setups while on Friday another optimization was merged.

With this merge, Mutter will now consider Wayland sub-surfaces for scanout. If a Wayland sub-surface is the top-most actor, it will now be considered for direct scanout as well.

Notably benefiting from this is Mozilla Firefox on Wayland with its usage of sub-surfaces, should you be running it full-screen, while other applications also stand to benefit.