SUMMARY When using Gamescope's Wayland backend from within a KWin DRM backend session, adaptive sync in gamescope will often jump up to my monitor's maximum refresh rate for a small blip before dropping back down to the game's actual frame rate. VRR recently got a bit of a rework in gamescope as of 3.15.x, and now the difference between gamescope's DRM backend and nested from Kwin has gotten noticeable if I look at my monitor's live OSD. I showed clips of this behavior difference to a gamescope dev and they said the cause of this was likely happening outside of gamescope itself if gamescope's VRR was working as expected in the DRM backend. I'll link two videos clips of the behavior as I'm seeing it on my monitor with gamescope's DRM backend compared to the nested within the Kwin drm backend along with my monitor's OSD. --- Gamescope DRM backend command (I use Valve's package that includes gamescope-session in this case): gamescope -e -h 2160 -w 7860 -r 120 --adaptive-sync --mangoapp -- steam -steamdeck -steamos3 -steampal -gamepadui Video of behavior w/ gamescope DRM backend: https://youtu.be/CwZpcCX-4V0 Nested gamescope from Plasma command: gamescope -h 2160 -w 7860 -f -r 120 --adaptive-sync --mangoapp -- %command% Video of behavior w/ gamescope nested on Plasma Wayland: https://youtu.be/vxfpLZ2b9lI STEPS TO REPRODUCE 1. Launch a game with a variation of those launch options to fit your display. Ideally, you want something that will max out the framerate a bit below your display's refresh rate 2. If your monitor has an OSD that allows you to observe the Variable Refresh Rate it is processing, enable it. OBSERVED RESULT Gamescope with the KWin DRM Backend has many noticeable jumps up to the display's set refresh rate rather than the game's refresh rate EXPECTED RESULT Gamescope with the KWin DRM Backend should have the same VRR behavior as Gamescope's DRM backend SOFTWARE/OS VERSIONS Operating System: CachyOS Linux KDE Plasma Version: 6.1.5 KDE Frameworks Version: 6.5.0 Qt Version: 6.7.2 Kernel Version: 6.11.0-rc7-1-cachyos-rc (64-bit) Graphics Platform: Wayland Processors: 64 × AMD Ryzen Threadripper 7970X 32-Cores Memory: 62.3 GiB of RAM Graphics Processor: AMD Radeon RX 7900 XTX Gamescope version: gamescope version 3.15.9 (gcc 14.2.1) ADDITIONAL INFORMATION No frametime variation is present in the MangoHud overlay
Same issue see: https://github.com/ValveSoftware/gamescope/issues/1617
Does this also happen if you just start the game without gamescope?
(In reply to Zamundaaa from comment #2) > Does this also happen if you just start the game without gamescope? I've been testing with Quake 2 RTX, and in my case it does not occur if you start the game without gamescope. Tested with both "Automatic" and "Always" adaptive sync settings in KDE.
(In reply to Zamundaaa from comment #2) > Does this also happen if you just start the game without gamescope? If you click the github link I posted two videos showcasing one with gamescope and one without, does not happen when gamescope is not used.
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🐛🧹 This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME.
(In reply to Matthew Schwartz from comment #3) > (In reply to Zamundaaa from comment #2) > > Does this also happen if you just start the game without gamescope? > I've been testing with Quake 2 RTX, and in my case it does not occur if you > start the game without gamescope. Tested with both "Automatic" and "Always" > adaptive sync settings in KDE. Then it must be a bug in gamescope
The fix for it to stop using mangoapp, and use mangohud inside gamescope. It works fine that way, when you use mangoapp the vrr doesn't work. Tested.
(In reply to Syntist from comment #8) > The fix for it to stop using mangoapp, and use mangohud inside gamescope. It > works fine that way, when you use mangoapp the vrr doesn't work. > Tested. This is just mot true. Look at the github link I posted above I sent videos of it with just gamescope and no mango app https://github.com/ValveSoftware/gamescope/issues/1617
Did you try yourself, without using mangoapp? cause for me that fixed the issue. Try to test without mangoapp and with in game fps monitor, or just mangohud
(In reply to joshuargiacone from comment #9) > (In reply to Syntist from comment #8) > > The fix for it to stop using mangoapp, and use mangohud inside gamescope. It > > works fine that way, when you use mangoapp the vrr doesn't work. > > Tested. > > This is just mot true. Look at the github link I posted above I sent videos > of it with just gamescope and no mango app > https://github.com/ValveSoftware/gamescope/issues/1617 oh you already tried it, weird for me it works without mangoapp, with mangoapp it doesn't work.
It definitely happens without mangoapp as well, but the bug depends on which game you are playing. Some work fine without mangoapp, others stutter even without it (like Quake 2 RTX). In any case, it also happens on Cosmic desktop with their VRR implementation, so as Xaver said it's not a KDE issue but a Gamescope issue.