Sandy Patterson, a couple follow ups: 1) Regarding kernel parameter acpi_osi=!Windows 2015 could you please advise why you need to use it, if at all? If you don't, you will want to remove it during your bisect tests to mimic a default install.
2) Regarding your Bug Description change, you change "consistently" to "it usually shows". Is this because it doesn't always cause a blank screen? If so, could you advise an approximate number (ex. 9/10 boots)? -- 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/1768139 Title: Kernel crash when booting laptop with hdmi monitor connected Status in linux package in Ubuntu: Incomplete Bug description: When I boot a Dell Inspiron 7559 with an external monitor connected to the hdmi port, it usually shows only a blank screen after grub and I have to hard power off the laptop. The issue is present when the bios and grub are in mirror mode to both screens. I can see the following stack trace in journalctl: syslog contains: kernel: Missing switch case (6) in intel_prepare_dp_ddi_buffers This occurs with both a Dell U2515H using an HDMI cord, and a HP Compaq LA2405wg connected via HDMI-to-DVI adapter. WORKAROUND: Keep the monitor unplugged until the Ubuntu loading screen shows up. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-20-generic 4.15.0-20.21 ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17 Uname: Linux 4.15.0-20-generic x86_64 ApportVersion: 2.20.9-0ubuntu7 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Mon Apr 30 17:22:20 2018 InstallationDate: Installed on 2018-04-28 (2 days ago) InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426) SourcePackage: linux-signed UpgradeStatus: No upgrade log present (probably fresh install) This is a fresh install. I have modified grub defaults to include "acpi_osi=!Windows 2015" --- ApportVersion: 2.20.9-0ubuntu7 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: apatterson 1965 F.... pulseaudio CurrentDesktop: ubuntu:GNOME DistroRelease: Ubuntu 18.04 HibernationDevice: RESUME=UUID=7b947b8e-de50-4ab6-b7f3-254a5dea924a InstallationDate: Installed on 2018-04-28 (9 days ago) InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426) MachineType: Dell Inc. Inspiron 7559 Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.15.0-20-generic root=UUID=77f1cfec-1fe4-4201-9a91-9f00a5d7782b ro quiet splash "acpi_osi=!Windows 2015" ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17 RelatedPackageVersions: linux-restricted-modules-4.15.0-20-generic N/A linux-backports-modules-4.15.0-20-generic N/A linux-firmware 1.173 Tags: bionic wayland-session Uname: Linux 4.15.0-20-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dialout dip lpadmin plugdev sambashare sudo wireshark _MarkForUpload: True dmi.bios.date: 09/26/2017 dmi.bios.vendor: Dell Inc. dmi.bios.version: 1.2.5 dmi.board.name: 0H0CC0 dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 10 dmi.chassis.vendor: Dell Inc. dmi.chassis.version: Not Specified dmi.modalias: dmi:bvnDellInc.:bvr1.2.5:bd09/26/2017:svnDellInc.:pnInspiron7559:pvr1.2.5:rvnDellInc.:rn0H0CC0:rvrA00:cvnDellInc.:ct10:cvrNotSpecified: dmi.product.family: Inspiron dmi.product.name: Inspiron 7559 dmi.product.version: 1.2.5 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1768139/+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