The issue did start appearing after an update on 17.10. I bought the Monitor on 29.11.2017, so it worked with the 17.10 kernel version around that time. Since HDMI on 4k only drives the Monitor @30Hz on my laptop, I bought a DP adapter. After the random screen black outs annoyed me too much I switched back to HDMI (around early this year). The monitor wasn't reliably recognized as a 4k monitor anymore.
- I installed the 4.16 Kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.16.1/ - Powered the laptop off - Switched from DP to HDMI adapter - Boot up with 4.16.1 kernel Monitor resolution was correctly identified - Rebooted with 4.16.1 kernel Monitor was not anymore correctly identified. Instead of 3840x2160@30hz the was at 1920x1080@60Hz Maybe relvant HDMI adapter info: My Lenovo Yoga 910 has a combined Type-C USB3 & DP 1.2 connector. The adapter is a LMP HDMI & USB adapter: https://www.lmp-adapter.com/en/products/cables--adapters/usb-c/lmp-usb-c-to-hdmi-multiport-adapter -- 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/1762986 Title: Display resolution of monitor via HDMI incorrectly identified Status in linux package in Ubuntu: Incomplete Bug description: I use a Philips BDM4037U 40'', 4k monitor. Connecting it via DP to my Lenovo 910 4k does work (except for random display blackouts). But when connecting it via HDMI the display resolution is sometimes correctly set (I cannot see a pattern when this works) but sometimes the display resolution is just set to FullHD, 1920x1080 Pixel @ 60Hz. Due to limitations of the supported HDMI protocol on my laptop I can only drive the display with 30Hz when in 4k mode. Which is totally fine for me. But this mode isn't correctly identified, most of the time. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-13-generic 4.15.0-13.14 [modified: boot/vmlinuz-4.15.0-13-generic] ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10 Uname: Linux 4.15.0-13-generic x86_64 ApportVersion: 2.20.9-0ubuntu4 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: thet 1429 F.... pulseaudio CurrentDesktop: ubuntu:GNOME Date: Wed Apr 11 12:00:28 2018 HibernationDevice: RESUME=UUID=bedd1248-32dd-43ca-be9f-28337086ea86 InstallationDate: Installed on 2018-04-09 (1 days ago) InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Beta amd64 (20180404) MachineType: LENOVO 80VF ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.15.0-13-generic.efi.signed root=UUID=998520ff-c841-45ab-8312-2bb876ae2a0b ro quiet splash vt.handoff=1 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 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 05/31/2017 dmi.bios.vendor: LENOVO dmi.bios.version: 2JCN39WW dmi.board.asset.tag: NO Asset Tag dmi.board.name: Agera dmi.board.vendor: LENOVO dmi.board.version: SDK0J40709 WIN dmi.chassis.asset.tag: NO Asset Tag dmi.chassis.type: 31 dmi.chassis.vendor: LENOVO dmi.chassis.version: Lenovo YOGA 910-13IKB dmi.modalias: dmi:bvnLENOVO:bvr2JCN39WW:bd05/31/2017:svnLENOVO:pn80VF:pvrLenovoYOGA910-13IKB:rvnLENOVO:rnAgera:rvrSDK0J40709WIN:cvnLENOVO:ct31:cvrLenovoYOGA910-13IKB: dmi.product.family: IDEAPAD dmi.product.name: 80VF dmi.product.version: Lenovo YOGA 910-13IKB dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1762986/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : email@example.com Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp