As stated in bug 1813831 thread, the issue is related to a change in the graphic driver's DPMS sequence. It was introduced in 4.15.0-44, and reverted in 4.15.0-45 made available for testing in the other bug's thread.
Meaning that it's not related to thunderbolt docks, nor docks at all, but to the display driver initializing the screen(s) through DPMS. My Dell 9370 shows the issue on each boot with -44 even when not connected to any external peripheral / dock / display, just with its internal screen. The issue is totally gone with -45. The DPMS change revert was already committed to upstream kernel patch train. -- 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/1813663 Title: External monitors does not work anymore 4.15.0-44 Status in linux package in Ubuntu: Confirmed Status in linux source package in Bionic: Fix Committed Bug description: I am using a docking station for my laptop. After install the 4.15.0-44 update my external monitors goes undetected after logging in or having the laptop closed. I am on 18.04.1 LTS with Intel® HD Graphics 620 (Kaby Lake GT2) Graphics. Going back to the 4.15.0-43 version makes it all work fine again. --- ProblemType: Bug ApportVersion: 2.20.9-0ubuntu7.5 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: jonas 2407 F.... pulseaudio CurrentDesktop: ubuntu:GNOME DistroRelease: Ubuntu 18.04 HibernationDevice: RESUME=UUID=80397b76-2ded-4f7d-adbf-dfdface8e2d4 InstallationDate: Installed on 2018-10-17 (103 days ago) InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725) MachineType: LENOVO 20HF004MMX Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-44-generic root=UUID=64cf1582-d574-4e2f-a40a-7942c40caf5d ro quiet splash vt.handoff=1 ProcVersionSignature: Ubuntu 4.15.0-44.47-generic 4.15.18 RelatedPackageVersions: linux-restricted-modules-4.15.0-44-generic N/A linux-backports-modules-4.15.0-44-generic N/A linux-firmware 1.173.3 Tags: bionic Uname: Linux 4.15.0-44-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip docker kvm lpadmin plugdev sambashare sudo _MarkForUpload: True dmi.bios.date: 09/14/2018 dmi.bios.vendor: LENOVO dmi.bios.version: N1WET51W (1.30 ) dmi.board.asset.tag: Not Available dmi.board.name: 20HF004MMX dmi.board.vendor: LENOVO dmi.board.version: SDK0J40697 WIN dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.modalias: dmi:bvnLENOVO:bvrN1WET51W(1.30):bd09/14/2018:svnLENOVO:pn20HF004MMX:pvrThinkPadT470s:rvnLENOVO:rn20HF004MMX:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone: dmi.product.family: ThinkPad T470s dmi.product.name: 20HF004MMX dmi.product.version: ThinkPad T470s dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1813663/+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
