[Bug 2170396] Re: Lenovo Legion screen flickering on Kubuntu 26.04 (Fixed by lowering brightness / 165Hz conflict)

** Tags added: kernel-daily-bug -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2170396 Title: Lenovo Legion screen flickering on Kubuntu 26.04 (Fixed by lowering brightness / 165Hz conflict) Status in linux package in Ubuntu: New Bug description: I installed Kubuntu 26.04 on my Lenovo Legion laptop (NVIDIA graphics) and experienced severe screen flickering. Key behaviors observed: • The panel natively runs at 165.04Hz. • Forcing the refresh rate down to 60Hz via kscreen-doctor temporarily improved the flickering but did not resolve it. • Forcing "Discrete Graphics" in the BIOS resulted in a total black screen upon OS load. • Crucial Hardware Link: Lowering the screen brightness manually to 30% reduces the flickering to minimal/manageable levels, suggesting a power-delivery/backlight voltage or PWM conflict with the modern kernel's power-saving features. ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: linux-image-7.0.0-38-generic 7.0.0-38.38 ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14 Uname: Linux 7.0.0-38-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia ApportVersion: 2.34.1-0ubuntu0.1 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: jgw 1549 F.... pipewire jgw 1561 F.... wireplumber /dev/snd/controlC0: jgw 1561 F.... wireplumber /dev/snd/seq: jgw 1549 F.... pipewire CasperMD5CheckResult: unknown CurrentDesktop: KDE Date: Fri Oct 9 19:23:43 2026 InstallationDate: Installed on 2026-10-07 (2 days ago) InstallationMedia: Kubuntu 26.04.1 LTS "Resolute Raccoon" - Release amd64 (20260826.1) MachineType: LENOVO 82TF ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-38-generic root=UUID=3ad3b9bb-66ac-4411-a956-601a55f3254c ro quiet splash pcie_aspm=off acpi_backlight=native PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon. SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 03/03/2025 dmi.bios.release: 1.58 dmi.bios.vendor: LENOVO dmi.bios.version: JYCN58WW dmi.board.asset.tag: No Asset Tag dmi.board.name: LNVNB161216 dmi.board.vendor: LENOVO dmi.board.version: SDK0T76461WIN dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: Legion S7 16IAH7 dmi.ec.firmware.release: 1.55 dmi.modalias: dmi:bvnLENOVO:bvrJYCN58WW:bd03/03/2025:br1.58:efr1.55:svnLENOVO:pn82TF:pvrLegionS716IAH7:rvnLENOVO:rnLNVNB161216:rvrSDK0T76461WIN:cvnLENOVO:ct10:cvrLegionS716IAH7:skuLENOVO_MT_82TF_BU_idea_FM_LegionS716IAH7:pfaLegionS716IAH7: dmi.product.family: Legion S7 16IAH7 dmi.product.name: 82TF dmi.product.sku: LENOVO_MT_82TF_BU_idea_FM_Legion S7 16IAH7 dmi.product.version: Legion S7 16IAH7 dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2170396/+subscriptions