Using G-SYNC Compatible On Linux With NVIDIA's 418.30 Beta Driver
Taking many by surprise less than one month after NVIDIA announced "G-SYNC Compatible" in supporting FreeSync/Adaptive-Sync displays as an alternative to the more expensive dedicated G-SYNC monitors, the newest Linux beta graphics driver has support for this gamer-oriented feature. This comes just a matter of days after NVIDIA began shipping their Windows driver with this dynamic refresh rate feature that aims to eliminate or at least reduce tearing and stuttering.
Today's NVIDIA 418.30 Linux beta driver has the G-SYNC Compatible support. Officially, the Linux driver supports the same monitors as their Windows driver with maintaining the same whitelist. The officially supported G-SYNC Compatible displays are listed at NVIDIA.com. But as is also the case with Windows, other FreeSync / Adaptive-Sync monitors can work with the NVIDIA driver, just unofficially.
Should your display not be officially supported but does support this variable rate refresh technology, via the NVIDIA-Settings panel on the "X Server Display Configuration" page under the Advanced button is the option to "Allow G-SYNC on monitor not validated as G-SYNC Compatible". From there you can apply it while the rest of the G-SYNC Compatible Settings can be found on the OpenGL settings page. It's important to check the box from the display configuration page as otherwise the G-SYNC functionality will not work even though the other options will still be listed from the OpenGL settings area.
From the OpenGL settings area is the option for allowing G-SYNC/G-SYNC Compatible for OpenGL games/programs as well as having a visual indicator to show when G-SYNC is active.
With the visual indicator, in the upper right-hand corner of the display is the "G-SYNC" text when it's working while the rest of the time will indicate "Normal" rendering. This is convenient for seeing when G-SYNC is supposed to be working.
It's nice that this G-SYNC Compatible functionality can be quickly and easily activated from the NVIDIA Settings area compared to the initial open-source AMD FreeSync support requiring the need to run xrandr commands from the terminal, less friendly for inexperienced Linux users. And with this G-SYNC Compatible rollout, with NVIDIA's driver package you just need this beta driver and not have to worry about any other requirements (which is also the case with Radeon Software's PRO stack, if you are on a supported Linux distribution).
As with Windows, G-SYNC Compatible only works when connected via DisplayPort and there is no HDMI support currently (a similar limitation to AMD's FreeSync AMDGPU Linux support). G-SYNC Compatible is only supported with GeForce GTX 1000 series hardware and newer, including the latest GeForce RTX 2000 Turing graphics cards.
I've been testing out the G-SYNC Compatible support briefly so far today and it's been working out well. The displays I have been testing are the ASUS VP28U and two ASUS MG28U displays, all of which are FreeSync capable. Unfortunately, G-SYNC Compatible doesn't appear to work with multi-head setups, at least for the MG28U configuration I rely upon as my main desktop configuration. I'm waiting to hear back from NVIDIA whether they expect to be able to overcome this limitation in the future.
From my limited testing thus far, once activated this G-SYNC Compatible support has been working out well with the mentioned displays and different Pascal and Turing graphics cards. More testing to come. Also, rather ironic this beta Linux support comes while AMD's open-source FreeSync support will premiere as stable around the end of February. With the Linux 5.0 kernel is where there is finally the mainline FreeSync/VRR bits while in user-space the xf86-video-amdgpu patches are merged to mainline already and there is also the needed bits in Mesa 19.0, which should also be coming out as stable in about one month's time.
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