Intel Lands Adaptive-Sync/VRR Into Modesetting X.Org Driver
Months ago they posted the VRR patches for xf86-video-modesetting while now the patches have been merged to X.Org Server Git. These patches in turn are based on AMD's FreeSync/VRR support they added to the xf86-video-amdgpu driver.
With xf86-video-intel effectively being dead and unmaintained, xf86-video-modesetting is the X.Org driver in use on Intel paired with their kernel mode-setting driver. While their kernel-side work is still being settled, the X.Org DDX bits are now merged. This can benefit AMD Radeon Linux users as well who want to enjoy VRR when using xf86-video-modesetting rather than the xf86-video-amdgpu DDX.
While the xf86-video-modesetting driver is "generic" to KMS drivers, this VRR support isn't magic and does require the hardware/drivers with the KMS/DRM kernel code as well as the Mesa driver to properly support variable refresh rate. If those pieces don't support VRR, xf86-video-modesetting's option won't work with a given system.
The support was merged today to xserver Git. Besides needing to be using the very latest Git code, a new VariableRefresh xorg.conf option is added for flipping on the VRR support for a given output.
But as for when this X.Org Server / xf86-video-modesetting code will actually ship in a released version is currently unknown... The Git code is still tracking X.Org Server 1.21 that has now been in development about two and a half years, well off their prior six month release schedule. So far no one has managed to step up to serve as the xorg-server 1.21 release manager given Red Hat's diminishing interest in X.Org Server duties in favor of a Wayland-focused Linux desktop. So at this stage X.Org Server 1.21 might not materialize until 2021 but we'll see if these VRR patches end up being back-ported to a 1.20.x point release in the interim.