Valve Implements Opt-In VK_KHR_present_wait For Mesa Vulkan Drivers

[phoronix]

Phoronix: Valve Implements Opt-In VK_KHR_present_wait For Mesa Vulkan Drivers

Landing this week within Mesa 23.0 is an initial implementation of Vulkan's VK_KHR_present_wait extension, which Hans-Kristian Arntzen of Valve's Linux team and VKD3D-Proton notoriety has referred to as a "very useful" extension but due to current spec limitations is for now only being made opt-in via a DriConf option so it can be handled on a per-game/app basis...

https://www.phoronix.com/news/Mesa-VK_KHR_present_wait

[Gusar]

Steam Deck isn't the target for this extension, VR is. Low input latency and consistent frame pacing is important in VR to combat motion sickness.

[mbriar]

It is also automatically enabled without the need for DriConf opt-in if the application only enables surface extensions that all can support present_wait, which currently are x11 and display (of course wayland is problematic again, as expected). That also means that it's enabled for games on wine/proton by default, because wine only supports x11.

[mbriar]

Steam Deck isn't the target for this extension, VR is. Low input latency and consistent frame pacing is important in VR to combat motion sickness.

I'm not so sure about that, I think it's also needed to properly implement the d3d12 swapchain model in general, not just for VR.

[treba]

It is also automatically enabled without the need for DriConf opt-in if the application only enables surface extensions that all can support present_wait, which currently are x11 and display (of course wayland is problematic again, as expected). ...

To phrase it a bit differently, it's not enabled yet on modern/sophisticated windowing systems (also Android/Win).

[theriddick]

It's reasonable to think that if Valve continue to release VR headsets then they will want to make the OS echo-system built from a specific build of SteamOS under Linux.

AND given they have proven AMD SOC's can work in low power devices inc stand-alone VR perhaps, this support makes sense. However I think it will depend on how AMD's future SOC's perform since they'll need something at least 2-4x the performance of the Steam Deck for VR.