I'm having this issue on Debian testing as well, after an upgrade of Mesa packages from 20.3.5-1 to 21.2.4-1. The problem disappears after downgrading to version 20.3.5-1 of the packages and rebooting (packages in my case: libegl-mesa0 libegl1-mesa-dev libgl1-mesa-dev libgl1-mesa-dri libglapi-mesa libglx-mesa0 mesa-va-drivers mesa-vdpau-drivers mesa-vulkan-drivers libgbm1 libgbm-de).
Testing with versions in between from snapshot.debian.org reveals that it's still OK with 21.1.6-1 and the issue starts with 21.2.0-1. Other related reports that look like they might be about the same problem, all related to Mesa 21.2 (I'm seeing artifacts in Firefox and in Konsole as described, as well as in other applications): https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=994057 https://forum.manjaro.org/t/konsole-tmux-rendering-problems-horizontal-stripes/86975 Graphics card info from 'hwinfo' output: 49: PCI 02.0: 0300 VGA compatible controller (VGA) [Created at pci.386] Unique ID: _Znp.A3c8F1k8IIB SysFS ID: /devices/pci0000:00/0000:00:02.0 SysFS BusID: 0000:00:02.0 Hardware Class: graphics card Device Name: "Onboard IGD" Model: "Intel UHD Graphics 630 (Mobile)" Vendor: pci 0x8086 "Intel Corporation" Device: pci 0x3e9b "UHD Graphics 630 (Mobile)" SubVendor: pci 0x103c "Hewlett-Packard Company" SubDevice: pci 0x8610 Revision: 0x02 Driver: "i915" Driver Modules: "i915" Memory Range: 0xe4000000-0xe4ffffff (rw,non-prefetchable) Memory Range: 0xa0000000-0xafffffff (ro,non-prefetchable) I/O Ports: 0x4000-0x403f (rw) Memory Range: 0x000c0000-0x000dffff (rw,non-prefetchable,disabled) IRQ: 166 (44948 events) Module Alias: "pci:v00008086d00003E9Bsv0000103Csd00008610bc03sc00i00" Driver Info #0: Driver Status: i915 is active Driver Activation Cmd: "modprobe i915" Config Status: cfg=new, avail=yes, need=no, active=unknown ** Bug watch added: Debian Bug tracker #994057 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=994057 -- You received this bug notification because you are a member of Kubuntu Bugs, which is subscribed to kwin in Ubuntu. https://bugs.launchpad.net/bugs/1944951 Title: KDE delayed display update / konsole artifacts To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/kwin/+bug/1944951/+subscriptions -- kubuntu-bugs mailing list kubuntu-b...@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/kubuntu-bugs