Created attachment 147367 [details] "About this System" SUMMARY Some random portion of the screen flashes back and forth between current and recent content. STEPS TO REPRODUCE i have no idea what exactly triggers it other than carrying on and using the system. i fully updated manjaro again yesterday and booted up fresh today, and the bug is still here. i have seen this bug on unpredictable occasions ever since starting to use and enjoy manjaro last november. i guess it to be a kwin bug, as invoking any of various kwin functions, eg magnifying the screen, will promptly quell the manifestation, tho curiously, quite like my own usage patterns, it most often fools with my xterms, and particularly, when i use tmux to flip amongst showing various htop displays, tho by no means is it limited to that. OBSERVED RESULT When it manifests, an area of the screen flashes back and forth between what it's supposed to be showing, and what was showing recently. The area flashing might be an entire window, or only a small or large portion of a window. The period of flashing is often entirely regular, and often quite irregular, varying between several times per second, to a period of 2 or 3 seconds. EXPECTED RESULT Show current content. SOFTWARE/OS VERSIONS see attachment for current versions # inxi --admin --verbosity=7 --filter --width System: Kernel: 5.16.0-1-MANJARO x86_64 bits: 64 compiler: gcc v: 11.1.0 parameters: BOOT_IMAGE=/boot/vmlinuz-5.16-x86_64 root=UUID=b2d9c25b-03ab-4676-ae6e-cc4dce724d09 rw panic=30 udev.log_priority=3 Desktop: N/A wm: kwin_x11 vt: 1 dm: startx Distro: Manjaro Linux base: Arch Linux Machine: Type: Laptop System: LENOVO product: 20C6008SUS v: ThinkPad Edge E540 serial: <superuser required> Chassis: type: 10 serial: <superuser required> Mobo: LENOVO model: 20C6008SUS v: 0B98401 WIN serial: <superuser required> UEFI: LENOVO v: J9ETA2WW (2.28 ) date: 06/20/2018 Battery: ID-1: BAT0 charge: 17.6 Wh (51.6%) condition: 34.1/52.8 Wh (64.5%) volts: 11.3 min: 11.1 model: LGC LNV-45N1 type: Li-ion serial: <filter> status: Not charging Memory: RAM: total: 7.65 GiB used: 3.13 GiB (40.9%) RAM Report: permissions: Unable to run dmidecode. Root privileges required. CPU: Info: model: Intel Core i5-4200M bits: 64 type: MT MCP arch: Haswell family: 6 model-id: 0x3C (60) stepping: 3 microcode: 0x28 Topology: cpus: 1x cores: 2 tpc: 2 threads: 4 smt: enabled cache: L1: 128 KiB desc: d-2x32 KiB; i-2x32 KiB L2: 512 KiB desc: 2x256 KiB L3: 3 MiB desc: 1x3 MiB Speed (MHz): avg: 2494 high: 2495 min/max: 800/3100 scaling: driver: intel_cpufreq governor: schedutil cores: 1: 2494 2: 2495 3: 2494 4: 2495 bogomips: 19961 Flags: abm acpi aes aperfmperf apic arat arch_perfmon avx avx2 bmi1 bmi2 bts clflush cmov constant_tsc cpuid cpuid_fault cx16 cx8 de ds_cpl dtes64 dtherm dts epb erms est f16c flush_l1d fma fpu fsgsbase fxsr ht ibpb ibrs ida invpcid invpcid_single lahf_lm lm mca mce md_clear mmx monitor movbe msr mtrr nonstop_tsc nopl nx pae pat pbe pcid pclmulqdq pdcm pdpe1gb pebs pge pln pni popcnt pse pse36 pti pts rdrand rdtscp rep_good sdbg sep smep ss ssbd sse sse2 sse4_1 sse4_2 ssse3 stibp syscall tm tm2 tsc tsc_adjust tsc_deadline_timer vme xsave xsaveopt xtopology xtpr Vulnerabilities: Type: itlb_multihit status: KVM: VMX unsupported Type: l1tf mitigation: PTE Inversion Type: mds mitigation: Clear CPU buffers; SMT vulnerable Type: meltdown mitigation: PTI Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via prctl Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer sanitization Type: spectre_v2 mitigation: Full generic retpoline, IBPB: conditional, IBRS_FW, STIBP: conditional, RSB filling Type: srbds mitigation: Microcode Type: tsx_async_abort status: Not affected Graphics: Device-1: Intel 4th Gen Core Processor Integrated Graphics vendor: Lenovo driver: i915 v: kernel bus-ID: 00:02.0 chip-ID: 8086:0416 class-ID: 0300 Device-2: Realtek Integrated Camera type: USB driver: uvcvideo bus-ID: 3-12:7 chip-ID: 0bda:5719 class-ID: 0e02 serial: <filter> Display: server: X.Org 1.21.1.2 compositor: kwin_x11 driver: loaded: modesetting alternate: fbdev,vesa display-ID: :0 screens: 1 Screen-1: 0 s-res: 1920x2616 s-dpi: 96 s-size: 507x691mm (20.0x27.2") s-diag: 857mm (33.7") Message: Unable to show advanced data. Required tool glxinfo missing. Audio: Device-1: Intel Xeon E3-1200 v3/4th Gen Core Processor HD Audio vendor: Lenovo driver: snd_hda_intel v: kernel bus-ID: 00:03.0 chip-ID: 8086:0c0c class-ID: 0403 Device-2: Intel 8 Series/C220 Series High Definition Audio vendor: Lenovo driver: snd_hda_intel v: kernel bus-ID: 00:1b.0 chip-ID: 8086:8c20 class-ID: 0403 Device-3: SteelSeries ApS SteelSeries Arctis 7 type: USB driver: hid-generic,snd-usb-audio,usbhid bus-ID: 3-1:2 chip-ID: 1038:12ad class-ID: 0300 Sound Server-1: ALSA v: k5.16.0-1-MANJARO running: yes Sound Server-2: JACK v: 1.9.19 running: no Sound Server-3: PulseAudio v: 15.0 running: yes Sound Server-4: PipeWire v: 0.3.40 running: yes Network: Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Lenovo driver: r8169 v: kernel port: 3000 bus-ID: 03:00.0 chip-ID: 10ec:8168 class-ID: 0200 IF: enp3s0 state: up speed: 1000 Mbps duplex: full mac: <filter> IP v4: <filter> type: dynamic noprefixroute scope: global broadcast: <filter> IP v6: <filter> type: noprefixroute scope: link Device-2: Intel Wireless 7260 driver: iwlwifi v: kernel bus-ID: 04:00.0 chip-ID: 8086:08b2 class-ID: 0280 IF: wlp4s0 state: down mac: <filter> WAN IP: <filter> Bluetooth: Device-1: Intel Bluetooth wireless interface type: USB driver: btusb v: 0.8 bus-ID: 3-7:5 chip-ID: 8087:07dc class-ID: e001 Report: rfkill ID: hci0 rfk-id: 2 state: up address: see --recommends Logical: Message: No logical block device data found. RAID: Message: No RAID data found. Drives: Local Storage: total: 465.76 GiB used: 147.97 GiB (31.8%) SMART Message: Unable to run smartctl. Root privileges required. ID-1: /dev/sda maj-min: 8:0 vendor: HGST (Hitachi) model: HTS725050A7E635 size: 465.76 GiB block-size: physical: 4096 B logical: 512 B speed: 6.0 Gb/s type: HDD rpm: 7200 serial: <filter> rev: A8Z0 scheme: GPT Optical-1: /dev/sr0 vendor: MATSHITA model: DVD-RAM UJ8E2 rev: 1.00 dev-links: cdrom Features: speed: 24 multisession: yes audio: yes dvd: yes rw: cd-r,cd-rw,dvd-r,dvd-ram state: running Partition: ID-1: / raw-size: 415.84 GiB size: 408.31 GiB (98.19%) used: 147.93 GiB (36.2%) fs: ext4 dev: /dev/sda2 maj-min: 8:2 label: N/A uuid: b2d9c25b-03ab-4676-ae6e-cc4dce724d09 ID-2: /boot/efi raw-size: 476 MiB size: 475.1 MiB (99.80%) used: 38.7 MiB (8.1%) fs: vfat dev: /dev/sda1 maj-min: 8:1 label: N/A uuid: 1FEA-1CC9 Swap: Kernel: swappiness: 60 (default) cache-pressure: 100 (default) ID-1: swap-1 type: file size: 16 GiB used: 0 KiB (0.0%) priority: -2 file: /f/swapfile Unmounted: ID-1: /dev/sda3 maj-min: 8:3 size: 16.76 GiB fs: ntfs label: N/A uuid: 03FDF2F31548EC3F USB: Hub-1: 1-0:1 info: Full speed or root hub ports: 3 rev: 2.0 speed: 480 Mb/s chip-ID: 1d6b:0002 class-ID: 0900 Hub-2: 1-1:2 info: Intel Integrated Rate Matching Hub ports: 6 rev: 2.0 speed: 480 Mb/s chip-ID: 8087:8008 class-ID: 0900 Hub-3: 2-0:1 info: Full speed or root hub ports: 3 rev: 2.0 speed: 480 Mb/s chip-ID: 1d6b:0002 class-ID: 0900 Hub-4: 2-1:2 info: Intel Integrated Rate Matching Hub ports: 8 rev: 2.0 speed: 480 Mb/s chip-ID: 8087:8000 class-ID: 0900 Hub-5: 3-0:1 info: Hi-speed hub with single TT ports: 14 rev: 2.0 speed: 480 Mb/s chip-ID: 1d6b:0002 class-ID: 0900 Device-1: 3-1:2 info: SteelSeries ApS SteelSeries Arctis 7 type: Audio,HID driver: hid-generic,snd-usb-audio,usbhid interfaces: 6 rev: 1.1 speed: 12 Mb/s power: 100mA chip-ID: 1038:12ad class-ID: 0300 Device-2: 3-2:3 info: Dell KB216 Wired Keyboard type: Keyboard,HID driver: hid-generic,usbhid interfaces: 2 rev: 1.1 speed: 1.5 Mb/s power: 100mA chip-ID: 413c:2113 class-ID: 0300 Device-3: 3-6:4 info: Dell Optical Wheel Mouse type: Mouse driver: hid-generic,usbhid interfaces: 1 rev: 2.0 speed: 1.5 Mb/s power: 100mA chip-ID: 413c:3012 class-ID: 0301 Device-4: 3-7:5 info: Intel Bluetooth wireless interface type: Bluetooth driver: btusb interfaces: 2 rev: 2.0 speed: 12 Mb/s power: 100mA chip-ID: 8087:07dc class-ID: e001 Device-5: 3-11:6 info: Validity Sensors VFS5011 Fingerprint Reader type: <vendor specific> driver: N/A interfaces: 1 rev: 1.1 speed: 12 Mb/s power: 100mA chip-ID: 138a:0011 class-ID: ff00 serial: <filter> Device-6: 3-12:7 info: Realtek Integrated Camera type: Video driver: uvcvideo interfaces: 2 rev: 2.0 speed: 480 Mb/s power: 500mA chip-ID: 0bda:5719 class-ID: 0e02 serial: <filter> Hub-6: 4-0:1 info: Super-speed hub ports: 6 rev: 3.0 speed: 5 Gb/s chip-ID: 1d6b:0003 class-ID: 0900 Sensors: System Temperatures: cpu: 55.0 C mobo: N/A Fan Speeds (RPM): cpu: 0 Info: Processes: 213 Uptime: 1h 9m wakeups: 1 Init: systemd v: 249 tool: systemctl Compilers: gcc: N/A Packages: pacman: 1142 lib: 312 Shell: Bash v: 5.1.12 running-in: tmux-master2021 inxi: 3.3.11 # xrandr Screen 0: minimum 320 x 200, current 1920 x 2616, maximum 16384 x 16384 eDP-1 connected primary 1366x768+552+1848 (normal left inverted right x axis y axis) 344mm x 193mm 1366x768 60.01*+ 1280x720 60.00 59.99 59.86 59.74 1024x768 60.04 60.00 960x720 60.00 928x696 60.05 896x672 60.01 1024x576 59.95 59.96 59.90 59.82 960x600 59.93 60.00 960x540 59.96 59.99 59.63 59.82 800x600 60.00 60.32 56.25 840x525 60.01 59.88 864x486 59.92 59.57 700x525 59.98 800x450 59.95 59.82 640x512 60.02 700x450 59.96 59.88 640x480 60.00 59.94 720x405 59.51 58.99 684x384 59.88 59.85 640x400 59.88 59.98 640x360 59.86 59.83 59.84 59.32 512x384 60.00 512x288 60.00 59.92 480x270 59.63 59.82 400x300 60.32 56.34 432x243 59.92 59.57 320x240 60.05 360x202 59.51 59.13 320x180 59.84 59.32 VGA-1 connected 1366x768+553+1080 (normal left inverted right x axis y axis) 256mm x 274mm 1360x768 59.95* 60.02 1024x768 75.03 70.07 60.00 800x600 85.06 72.19 75.00 60.32 57.90 56.25 640x480 75.00 72.81 59.94 720x400 70.08 HDMI-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 698mm x 392mm 1920x1080 60.00*+ 59.94 30.00 24.00 29.97 23.98 1920x1080i 60.00 59.94 1680x1050 59.88 1280x1024 75.02 60.02 1440x900 59.90 1280x960 60.00 1360x768 60.02 1280x800 59.91 1152x864 75.00 1280x720 60.00 60.00 30.00 59.94 29.97 24.00 23.98 1024x768 75.03 70.07 60.00 800x600 72.19 75.00 60.32 720x480 60.00 59.94 720x480i 60.00 59.94 640x480 75.00 72.81 60.00 59.94 720x400 70.08 DP-1 disconnected (normal left inverted right x axis y axis)
yesterday while recording my screen i happened to capture an occurrence of this bug in a video. this particular occurrence was flashing a mosaic of areas not including the top focused window, back and forth between current correct content and a curious green pattern, with a period of numerous times per second. as usual with occurrences of this bug the manifestation quelled upon a particular kwin event, in this case changing focus from one window to another.
one of the most frequent manifestations of this bug, likely the best way to quickly reproduce the bug at will, is when i hover over the firefox nightly icon on the kde taskbar, then hover over the individual nightly windows that popup above the icon. kwin meanwhile shows only that window, no others, and of course the background images. as i move thus from one firefox window to another, it's usually within a minute or two that one of the windows will appear flashing, rather than static, usually a slightly irregular period of around twice per second.
Created attachment 147570 [details] flashing firefox nightly windows, see comment 2
Created attachment 148060 [details] described in comment 1 albeit comment 1 inaccurate regarding focus changes for this particular manifestation
I can confirm the problem and can reliably reproduce it with windows of selected applications, namely, Emacs, Firefox, and Hamster (a time tracker). I cannot reproduce it with Qt applications or pure X11 applications like xlogo or glxgears. Although my sample is small, I suppose it might only affect GTK applications. To reproduce, it is easiest to assign key combinations to “Maximize Window” and “Quick Tile Window to the Left”. When maximizing a window of an affected application and tiling it to the left afterwards, the right portion of the screen keeps flashing the previous half of the window. It also works with just toggling maximize, however, then the flashing portion is not so easily defined. When enabling the “Show Paint” desktop effect and when there are only few screen updates, it seems to me that outdated content is shown with every third screen update. I therefore suspect that KWin uses triple buffering and one of the buffers is not correctly invalidated. But of course I am just guessing here. Operating System: Arch Linux KDE Plasma Version: 5.25.0 KDE Frameworks Version: 5.95.0 Qt Version: 5.15.5 Kernel Version: 5.18.5-arch1-1 (64-bit) Graphics Platform: X11 Processors: 8 × Intel® Core™ i5-8250U CPU @ 1.60GHz Graphics Processor: Mesa Intel® UHD Graphics 620 Manufacturer: LENOVO Product Name: 20L50000GE System Version: ThinkPad T480 GTK2 Versions: 2.24.33-2 GTK3 Version: 1:3.24.34-1 ``` $ kwin_x11 --replace OpenGL vendor string: Intel OpenGL renderer string: Mesa Intel(R) UHD Graphics 620 (KBL GT2) OpenGL version string: 4.6 (Compatibility Profile) Mesa 22.1.1 OpenGL shading language version string: 4.60 Driver: Intel GPU class: Kaby Lake OpenGL version: 4.6 GLSL version: 4.60 Mesa version: 22.1.1 X server version: 1.21.1 Linux kernel version: 5.18.5 Requires strict binding: yes GLSL shaders: yes Texture NPOT support: yes Virtual Machine: no ```
… continuing my previous comment: The “Maximize” desktop effect needs to be disabled for the problem to occur.
Today i was in a zoom meeting, suddenly kwin stopped updating the zoom window and started flpping the zoom window between two recent frames, rather amusing to see someone's mouth flapping and someone else batting their head over and over. When i moved the mouse around from window to window, the change in window focus some of the time would cause kwin to start flipping the zoom window between two newer more recent frames. And then the flashing cancer spread from the zoom window only at first to other windows too. i then opened systemsettings and changed from extreme to low focus stealing prevention, whereupon kwin immediately started working properly. i then changed back to extreme focus stealing prevention, and kwin remained functioning properly. Today's episode was brought to me on opensuse tumbleweed kde kwin5 5.25.5-1.2.
in response to comments 6 and 7, from my experience it seems that any of many various changes in circumstances, be they changes in settings or changes in focus, can seem in the moment to serve as trigger for a manifestation of this bug to come forth, or as trigger for this bug to fall latent again.
as of recently any use of the magnifier desktop effect via a shortcut key and then moving the mouse to a new position brings manifestation of this bug, typically 3 sets of recent positions of the magnified box are displayed in rotation for 1 second each, in sync with the one second updates to my kde taskbar clock. opensuse tumbleweed kwin5|5.27.10-1.2|x86_64||repo-oss i have to say i'm ambivalent about having reported this bug as it's a delightfully entertaining bug!