[Bug 2156644] Re: GNOME Panel & Activities Overview workspace thumbnails flickering issue

Update: The original apport report was generated using ubuntu-bug while the system was actively exhibiting the flickering/corruption symptoms with the 3-display configuration attached. I performed additional testing and found a significant correlation with monitor configuration. With my original multi-monitor setup (2 ASUS monitors + 1 TCL TV), GNOME Shell produced repeated errors of the form: gbm_surface_lock_front_buffer failed Failed to query buffer age, got error 3003 These sessions also exhibited Activities Overview flickering, top-panel flickering, and occasional window-edge artifacts. The issue reproduced across multiple kernels, including mainline 7.0.12-070012-generic. On that kernel the symptoms appeared after roughly 10 minutes rather than several hours, suggesting the newer kernel affected time-to-failure but did not eliminate the issue. I have since tested using a single display only (Sony TV over HDMI) and have been unable to reproduce the problem. In the single-display configuration there is no visible flickering, no rendering corruption, and the GBM/buffer-age errors are absent. Error counts observed: 3-display configuration: journalctl -b | grep -c "gbm_surface_lock_front_buffer failed" => 4495 journalctl -b | grep -c "Failed to query buffer age" => 3967 Single-display configuration: journalctl -b | grep -c "gbm_surface_lock_front_buffer failed" => 0 journalctl -b | grep -c "Failed to query buffer age" => 0 Perhaps this appears to be a GNOME Shell/Mutter multi-monitor rendering issue, or an interaction involving multiple outputs, rather than a kernel-only or i915-only problem. This multi-monitor configuration was used for an extended period on Ubuntu 24.04 without exhibiting the Activities Overview flickering or related rendering corruption. The issue first appeared after upgrading to Ubuntu 26.04. While I cannot rule out other software changes that occurred as part of the upgrade, I did not observe this behavior on the same hardware prior to the upgrade. -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2156644 Title: GNOME Panel & Activities Overview workspace thumbnails flickering issue Status in linux package in Ubuntu: New Bug description: GNOME Activities Overview workspace thumbnails begin flickering after several hours of uptime on Ubuntu 26.04 LTS with GNOME Shell 50.1 running on Wayland and Intel Alder Lake-N integrated graphics (i915 driver). System: Ubuntu 26.04 (upgraded from 24.04) GNOME Shell 50.1 / Mutter 50.1 Wayland session (no Xorg session available) Intel Alder Lake-N UHD Graphics (i915 driver) Three displays (all 1920×1080 @ 60Hz) Symptoms: After several hours of uptime, GNOME Activities Overview becomes visually corrupted. Specifically, workspace thumbnails flicker immediately upon entering Overview (Super key or hot corner). The flickering is limited to Overview workspace thumbnails and GNOME top bar. Normal desktop, application windows remain stable and unaffected. Exiting Overview immediately returns the desktop to normal. Logging out and back in resolves the issue temporarily, but it returns in minutes, rebooting it returns after several hours. No GPU resets, hangs, or DRM errors appear in journalctl. I’ve tried: Kernel parameter: intel_idle.max_cstate=1 Appears to delay or partially change the symptoms, but the issue still occurs. Kernel parameter: i915.enable_dc=0 Initially seemed to reduce symptoms, but the issue still returned. Adding i915.enable_psr=0 i915.enable_fbc=0 to GRUB also did not solve the issue. Tested different kernels (including older kernel) No change in long-term behavior. Disabled a couple of third-party GNOME extensions (still using default Ubuntu extensions). Observations: The issue does not affect application rendering or the desktop outside of Activities Overview. It appears only after extended uptime (hours), not immediately after login. The issue is reproducible across reboots and kernel versions. No relevant errors in journalctl related to i915, DRM, or GPU resets. ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: linux-image-7.0.0-15-generic 7.0.0-15.15 ProcVersionSignature: Ubuntu 7.0.0-15.15-generic 7.0.0 Uname: Linux 7.0.0-15-generic x86_64 ApportVersion: 2.34.0-0ubuntu2 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Fri Jun 12 19:46:59 2026 InstallationDate: Installed on 2023-10-25 (962 days ago) InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220419) MachineType: GMKtec NucBox G2 ProcEnviron: LANG=en_US.UTF-8 PATH=(custom, no user) SHELL=/bin/bash TERM=xterm-256color XDG_RUNTIME_DIR=<set> ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-15-generic root=UUID=4f8f8593-25f0-4c7b-8445-d8bc2891550a ro quiet splash i915.enable_psr=0 i915.enable_fbc=0 crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M SourcePackage: linux UpgradeStatus: Upgraded to resolute on 2026-06-09 (3 days ago) dmi.bios.date: 06/08/2023 dmi.bios.release: 5.27 dmi.bios.vendor: American Megatrends International, LLC. dmi.bios.version: 5.27 dmi.board.asset.tag: Default string dmi.board.name: GMKtec dmi.board.vendor: GMKtec dmi.board.version: Default string dmi.chassis.asset.tag: Default string dmi.chassis.type: 0 dmi.chassis.vendor: Default string dmi.chassis.version: Default string dmi.modalias: dmi:bvnAmericanMegatrendsInternational,LLC.:bvr5.27:bd06/08/2023:br5.27:svnGMKtec:pnNucBoxG2:pvrDefaultstring:rvnGMKtec:rnGMKtec:rvrDefaultstring:cvnDefaultstring:ct0:cvrDefaultstring:skuG2:pfaMINI: dmi.product.family: MINI dmi.product.name: NucBox G2 dmi.product.sku: G2 dmi.product.version: Default string dmi.sys.vendor: GMKtec To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2156644/+subscriptions