Flicker Resolved with intel_iommu=igfx_off on ThinkPad T490 (UHD Graphics 620)
Hello everyone, I wanted to report that I’ve successfully resolved the screen flickering issue on my Lenovo ThinkPad T490 with Intel UHD Graphics 620. The flickering occurred across the entire GNOME interface in Wayland, particularly when clicking in the bottom-right area (~1740,1030 on 1920x1080), and was accompanied by "CPU pipe A FIFO underrun" errors in the logs (sudo dmesg | grep -i i915). I’m using Ubuntu 24.04.3 LTS with kernel 6.14.0-1012-oem. Initially, I tried i915.enable_psr=0 and i915.enable_fbc=0 without success. Then, following suggestions, I added intel_iommu=igfx_off to GRUB_CMDLINE_LINUX_DEFAULT (resulting in "quiet splash i915.enable_psr=0 i915.enable_fbc=0 intel_iommu=igfx_off"), ran sudo update-grub, and rebooted. Since then, I haven’t experienced any flickering, even after several hours of use and repeated clicks in the affected area. The current logs (sudo dmesg | grep -i i915) show no FIFO underrun errors or significant warnings after the change. I’m using only the built-in display at 1920x1080, 60 Hz, with 100% scaling. The previous i915_hpd_poll_init_work hogged CPU warnings seem to have disappeared in this log capture, which might indicate overall stabilization. I hope this solution helps other users with similar hardware. Thanks to the community for the support! Recent logs: [ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-6.14.0-1012-oem root=UUID=16a43dc7-79f5-4e8b-9bbd-1eb5c40705ee ro quiet splash i915.enable_psr=0 i915.enable_fbc=0 intel_iommu=igfx_off vt.handoff=7 [ 0.082613] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-6.14.0-1012-oem root=UUID=16a43dc7-79f5-4e8b-9bbd-1eb5c40705ee ro quiet splash i915.enable_psr=0 i915.enable_fbc=0 intel_iommu=igfx_off vt.handoff=7 [ 4.353070] i915 0000:00:02.0: enabling device (0006 -> 0007) [ 4.353878] i915 0000:00:02.0: [drm] Found coffeelake/ult (device ID 3ea0) integrated display version 9.00 stepping N/A [ 4.375317] i915 0000:00:02.0: vgaarb: deactivate vga console [ 4.386565] i915 0000:00:02.0: vgaarb: VGA decodes changed: olddecodes=io+mem,decodes=io+mem:owns=mem [ 4.389087] i915 0000:00:02.0: [drm] Finished loading DMC firmware i915/kbl_dmc_ver1_04.bin (v1.4) [ 4.439481] mei_hdcp 0000:00:16.0-b638ab7e-94e2-4ea2-a552-d1c54b627f04: bound 0000:00:02.0 (ops i915_hdcp_ops [i915]) [ 4.493588] [drm] Initialized i915 1.6.0 for 0000:00:02.0 on minor 1 [ 4.549156] fbcon: i915drmfb (fb0) is primary device [ 4.549163] i915 0000:00:02.0: [drm] fb0: i915drmfb frame buffer device [ 4.631892] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915]) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2062951 Title: Random flickering with Intel i915 (Gen9 GPUs in 6th-8th gen CPUs) on Linux 6.8 To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/2062951/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
