https://bugs.kde.org/show_bug.cgi?id=527624
kuqquk <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- Component|general |platform-drm CC| |[email protected], | |[email protected] Platform|CachyOS |Neon --- Comment #1 from kuqquk <[email protected]> --- Similar issue here. DESCRIPTION On a hybrid-graphics laptop (Intel Raptor Lake iGPU + NVIDIA RTX 2000 Ada Laptop GPU), an external monitor connected to a DisplayPort output wired to the NVIDIA GPU flickers whenever the screen repaints: moving the mouse, clicking, or typing all trigger it. The laptop's internal panel (driven by the Intel iGPU) is unaffected. The same monitor worked without flickering on this machine before a recent update. STEPS TO REPRODUCE 1. Log into a Plasma Wayland session on a hybrid Intel + NVIDIA laptop (KWin renders on the Intel iGPU by default). 2. Connect an external monitor to an output driven by the NVIDIA GPU (here DP-5 on card2). 3. Move the mouse or type on the keyboard. OBSERVED RESULT The external monitor flickers on every repaint. EXPECTED RESULT No flickering, as before. WORKAROUND Making the NVIDIA GPU the primary render device fixes it completely: export KWIN_DRM_DEVICES=/dev/dri/card2:/dev/dri/card1 This suggests a problem in the multi-GPU path that copies frames from the Intel GPU to the NVIDIA output. ALREADY RULED OUT - Refresh rate / link bandwidth: switching from 3840x2160@100 Hz to 60 Hz makes no difference. - VRR: the monitor reports VRR as incapable. - Input devices: libinput debug-events shows no unexpected events. - No kernel/DRM errors in the journal while the flicker happens. SOFTWARE/OS VERSIONS OS: KDE Neon User Edition KDE Plasma Version: 6.8.1 KDE Frameworks Version: 6.31.0 Qt Version: 6.11.1 Kernel Version: 7.0.0-38-generic (64-bit) NVIDIA driver: 595.99.02 (open kernel module) Graphics platform: Wayland ADDITIONAL INFORMATION Hardware: Intel Raptor Lake-S UHD Graphics (i915) + NVIDIA RTX 2000 Ada Generation Laptop GPU (nvidia-drm, modeset enabled). External monitor: DisplayPort, scale 1.75. Attached: KWin supportInformation, kscreen-doctor output, GPU info and KWin journal, all captured with the workaround disabled while the flicker was occurring. -- You are receiving this mail because: You are watching all bug changes.
