> Did this issue start happening after an update/upgrade? I can't tell exactly. The system is just a week old, but I recall that there has been a kernel upgrade. HDMI had some issues (i.e. wouldn't connect) via Lenovo's docking station last week, it worked today though when connected to the notebook's HDMI port directly.
I've tried with my somewhat aged (but okay) LG Flatron M2380D-PZ monitor, and there is some trouble: - The monitor is apparently detected when (the HDMI cable is attached and) the monitor is turned on: - The second monitor shows up in System Settings > Devices > Displays for about a second. Before that the notebook screen turns black for about half a second. - Then the second monitor disappears from the Settings again, and the external monitor shows "No Signal" That is an issue only since Ubuntu 18.04 (I can't tell whether it's related to a specific kernel), because the monitor used to work with my Dell XPS 13 Developer Edition, which is running the very same configuration of Ubuntu (18.04 LTS developer version) and behaves similarly now, until Ubuntu 17.10 not too long ago. I'm a bit reluctant building the latest kernel. If it's really really important I may give it a shot. -- 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/1763202 Title: Lenovo X1 Carbon 6th Gen. HDMI not working for external monitor Status in linux package in Ubuntu: Incomplete Bug description: I have an X1 Carbon 6th Gen. (Intel Core i7 8th Gen, 16 GB RAM, 512 GB SSD). When I try to attach an external monitor via an HDMI cable the monitor receives no signal. Similarly, when I use the Thunderbold dock and attach two monitors (one via HDMI, one with DisplayPort) only the monitor attached with DisplayPort works; the monitor attached with HDMI stays black. This made me think if this is really a bug in the software. I saw people describing this issue with Windows installed; the solution was to hit a special key combination. Unfortunately, the multimedia keys all not all functional, specifically the F7 key, which seems to meant for "activate external monitor", has no function. --- ApportVersion: 2.20.9-0ubuntu4 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: peter 3510 F.... pulseaudio /dev/snd/controlC0: peter 3510 F.... pulseaudio CurrentDesktop: ubuntu:GNOME DistroRelease: Ubuntu 18.04 HibernationDevice: RESUME=UUID=8aee1825-7879-4889-8de3-e57900548385 InstallationDate: Installed on 2018-04-06 (5 days ago) InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180403) MachineType: LENOVO 20KHCTO1WW Package: linux (not installed) ProcFB: 0 EFI VGA 1 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.15.0-13-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=1 ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10 RelatedPackageVersions: linux-restricted-modules-4.15.0-13-generic N/A linux-backports-modules-4.15.0-13-generic N/A linux-firmware 1.173 Tags: bionic Uname: Linux 4.15.0-13-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip docker lpadmin plugdev sambashare sudo _MarkForUpload: True dmi.bios.date: 02/27/2018 dmi.bios.vendor: LENOVO dmi.bios.version: N23ET37W (1.12 ) dmi.board.asset.tag: Not Available dmi.board.name: 20KHCTO1WW dmi.board.vendor: LENOVO dmi.board.version: SDK0J40709 WIN dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.modalias: dmi:bvnLENOVO:bvrN23ET37W(1.12):bd02/27/2018:svnLENOVO:pn20KHCTO1WW:pvrThinkPadX1Carbon6th:rvnLENOVO:rn20KHCTO1WW:rvrSDK0J40709WIN:cvnLENOVO:ct10:cvrNone: dmi.product.family: ThinkPad X1 Carbon 6th dmi.product.name: 20KHCTO1WW dmi.product.version: ThinkPad X1 Carbon 6th dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1763202/+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
