Could be similar to what you can do with libstrangle.

libstrangle just limits the framerate. However this enhanced sync can benefit you if your framerate is higher than max monitor refresh rate. So it's not the same.

From reading about it, it seems it can be similar to Vulkan mailbox presentation mode. But I'd be interested in some expert opinion on it.

Related video: https://www.youtube.com/watch?v=uzp8z1i5-Hc



Last edited by Shmerl on 14 Feb 2022 at 5:48 pm UTC

Quoting: Shmerllibstrangle just limits the framerate.

It also has mailbox mode (which sounds a lot like that image) and an adaptive mode.

Quoting: EhvisIt also has mailbox mode (which sounds a lot like that image) and an adaptive mode.

Ah, yes it has a few options. But I don't think you need libstrangle for mailbox at least? You can simply do something like:

MESA_VK_WSI_PRESENT_MODE=mailbox

What is adaptive mode? Isn't it a regular adaptive sync? I.e. why do you need a layer for that?

Last edited by Shmerl on 14 Feb 2022 at 6:11 pm UTC

What I'm interested is third picture in AMD's diagram. I.e. adaptive sync in range, enhanced sync / mailbox above the range.

Last edited by Shmerl on 14 Feb 2022 at 6:09 pm UTC

If mesa has it, then it's even easier. I'm pretty sure that mailbox is the same as your picture although I am not clear on what they do when the fps drops below the refresh rate.

No idea what adaptive mode does exactly. Nothing the libstrange readme doesn't explain things in detail.

Sounds like the 3d pic is mailbox + freesync. Does freesync work independent of the vsync setting?

Last edited by Ehvis on 14 Feb 2022 at 6:18 pm UTC

From what I remember, you need to keep vsync setting in older games off for adaptive sync to kick in. I suppose more modern games should be aware, that syncing logic today is more complicated than simple vsync on / vsync off, so I don't really know what they do when you toggle that setting in the game. Some games may be even don't have it and provide multiple options that match Vulkan semantics better:

https://www.khronos.org/registry/vulkan/specs/1.3-extensions/man/html/VkPresentModeKHR.html

Besides mailbox (enhanced sync?) and fifo (classic vsync?) there is also something called "fifo relaxed".

Last edited by Shmerl on 14 Feb 2022 at 6:36 pm UTC

Some details on controlling Mesa from the env vars for it:

https://gitlab.freedesktop.org/mesa/mesa/-/blob/main/docs/envvars.rst

envvar: MESA_VK_WSI_PRESENT_MODE
overrides the WSI present mode clients specify in VkSwapchainCreateInfoKHR::presentMode.
Values can be fifo, relaxed, mailbox or immediate.

Last edited by Shmerl on 14 Feb 2022 at 6:42 pm UTC

About what happens with adaptive sync if you set mailbox - I haven't tested it. I'll look into that.

I don't know how to replicate that functionality in Linux, but I can tell you that it's practically a no-show on Windows too. Sure it exists, but basically for years now there has been persistent bugs with it (usually render to black screen if Enhanced Sync is on) to the point where it's at the bottom of the patch notes and joked about constantly.

Interesting. I have no idea about situation on Windows in this regard. But I've seen this mentioned, so I'm curious how this can be used on Linux.