https://bugs.kde.org/show_bug.cgi?id=461743
Bug ID: 461743 Summary: iGPU multi-monitor: Part of screen missing on secondary (integrated GPU) Classification: Plasma Product: kwin Version: 5.26.3 Platform: Gentoo Packages OS: Linux Status: REPORTED Severity: normal Priority: NOR Component: wayland-generic Assignee: kwin-bugs-n...@kde.org Reporter: andrewammerl...@gentoo.org Target Milestone: --- Created attachment 153696 --> https://bugs.kde.org/attachment.cgi?id=153696&action=edit iGPU connected monitor on 1440x900@75 SUMMARY I recently replaced my (AMD) GPU with an Intel Arc. Unfortunately my motherboard does not like booting from it for weird reasons. This means I am (still) stuck using the integrated GPU as boot GPU and therefore require the dual-GPU multi-monitor feature. Though this used to work fine with the AMD dGPU + Intel iGPU combination, the Intel dGPU + Intel iGPU combination is producing a weird screen artefact on the monitors connected to the iGPU (see attached photo). SDDM (which runs in X on the iGPU) renders fine. The mouse does actually move over the missing black area, and I can even interact with buttons which are hidden by the black part. If I cycle through the supported resolutions the black area changes, and for specific resolutions even goes away. The problem is not with the monitor, cable, or output. I tested a different cable with a different monitor, on a DV-D instead of VGA output and got the exact same result. This might be a mesa rendering bug instead of a kwin bug? There is also a separate issue where kscreen/kwin sometimes does not list all supported resolutions/refresh rates for monitors connected to the Intel dGPU (e.g. 80, 100, 144 is missing, 60 is the highest option). However. I have not yet found the exact conditions that produce that bug, and it feels more like a kernel level problem so it might not be relevant here. STEPS TO REPRODUCE 1. Enable Multi-Monitor in BIOS on a Intel dGPu, Intel iGPU system 2. Connect a display to the dGPU and iGPU 3. Start a wayland session OBSERVED RESULT The bottom part of the monitors connected to the iGPU is "hidden" by a weird black part. EXPECTED RESULT The full display is visible SOFTWARE/OS VERSIONS Linux/KDE Plasma: Gentoo Linux (kernel 6.0.8, mesa 22.2.3) KDE Plasma Version: 5.26.3 KDE Frameworks Version: 5.99.0 Qt Version: 5.15.5 ADDITIONAL INFORMATION Intel i9-9900KS UHD Graphics 630 (CFL GT2) + Intel Arc A770 Graphics (DG2) -- You are receiving this mail because: You are watching all bug changes.