Please try mainline kernels (https://kernel.ubuntu.com/~kernel- ppa/mainline/), for example, 5.8rc6.
If it works, please try 5.6 and then repeat bisecting. This can help identify whether fixes are available and what fix is. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1888695 Title: (Thinkpad L480) Booting hangs at the spinner screen when an HDMI cable is connected to an external monitor Status in linux package in Ubuntu: Confirmed Bug description: Laptop: Lenovo ThinkPad L480 External monitor: Philips 276E8VJSB (4K UHD) Steps to reproduce the problem: 1. While turned off, connect an HDMI cable between the laptop and an external monitor 2. Turn on the laptop 3. Booting hangs at the spinner screen, where it's written "Press Ctrl+C to skip" The laptop boots up normally when the HDMI cable is not connected. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.4.0-42-generic 5.4.0-42.46 ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44 Uname: Linux 5.4.0-42-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.4 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: amr 1875 F.... pulseaudio CasperMD5CheckResult: skip CurrentDesktop: ubuntu:GNOME Date: Thu Jul 23 16:08:14 2020 InstallationDate: Installed on 2020-04-26 (88 days ago) InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423) Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 004: ID 5986:2113 Acer, Inc Integrated Camera Bus 001 Device 002: ID 0461:4e57 Primax Electronics, Ltd HID compliant device Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: LENOVO 20LTS01800 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=de_DE.UTF-8 SHELL=/bin/bash ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-42-generic root=UUID=a25a653c-6a2a-4954-bd98-bfe2582a2b74 ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-5.4.0-42-generic N/A linux-backports-modules-5.4.0-42-generic N/A linux-firmware 1.187.1 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 12/18/2019 dmi.bios.vendor: LENOVO dmi.bios.version: R0QET60W (1.37 ) dmi.board.asset.tag: Not Available dmi.board.name: 20LTS01800 dmi.board.vendor: LENOVO dmi.board.version: Not Defined dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.modalias: dmi:bvnLENOVO:bvrR0QET60W(1.37):bd12/18/2019:svnLENOVO:pn20LTS01800:pvrThinkPadL480:rvnLENOVO:rn20LTS01800:rvrNotDefined:cvnLENOVO:ct10:cvrNone: dmi.product.family: ThinkPad L480 dmi.product.name: 20LTS01800 dmi.product.sku: LENOVO_MT_20LT_BU_Think_FM_ThinkPad L480 dmi.product.version: ThinkPad L480 dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1888695/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
