4K 60Hz with RGB colour requires that: 1. The computer's HDMI port supports HDMI 2.0; and 2. The HDMI cable supports HDMI 2.0; and 3. The screen supports HDMI 2.0 (https://en.wikipedia.org/wiki/HDMI#Refresh_frequency_limits_for_standard_video)
It appears #1 is true because: https://www.intel.com/content/www/us/en/products/boards-kits/nuc/kits/nuc8i5beh.html It appears #3 is true because: https://www.lg.com/au/it-monitors/lg-27UD58 So I suggest the problem most likely is that you're not using a high enough quality HDMI cable. Try replacing the cable with another that you are sure supports HDMI 2.0. Although that is for 8-bit true colour only... If you are really wanting to use "deep color" (10-bit) at 4K 60Hz then you will need a computer, cable and monitor that supports HDMI 2.1 (https://en.wikipedia.org/wiki/HDMI#Refresh_frequency_limits_for_HDR10_video). Unfortunately both your computer and monitor only support HDMI 2.0 so do not support deep colour modes of 4K 60Hz. ** Package changed: xorg (Ubuntu) => ubuntu ** Changed in: ubuntu Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1808653 Title: xorg? 4k only at 30hzIntel® Iris™ Plus 655 Status in Ubuntu: Incomplete Bug description: 1. as you can see in the error log there is an authorisation issue too. 2. I can not select 4k video with 60hz. The LG 27ud58-b does support it and the Intel® Iris™ Plus 655 too. 3. When the lg monitor is in HDMI ultra hd deep color mode then the screen keeps blinking in 4k resolution. ProblemType: Bug DistroRelease: Ubuntu 18.10 Package: xorg 1:7.7+19ubuntu8 ProcVersionSignature: Ubuntu 4.18.0-12.13-generic 4.18.17 Uname: Linux 4.18.0-12-generic x86_64 ApportVersion: 2.20.10-0ubuntu13.1 Architecture: amd64 BootLog: Error: [Errno 13] Toegang geweigerd: '/var/log/boot.log' CompositorRunning: None CurrentDesktop: XFCE Date: Sat Dec 15 19:48:32 2018 DistUpgraded: Fresh install DistroCodename: cosmic DistroVariant: ubuntu ExtraDebuggingInterest: Yes, if not too technical GraphicsCard: Intel Corporation Device [8086:3ea5] (rev 01) (prog-if 00 [VGA controller]) Subsystem: Intel Corporation Device [8086:2074] InstallationDate: Installed on 2018-12-13 (2 days ago) InstallationMedia: Xubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.2) MachineType: Intel(R) Client Systems NUC8i5BEH ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.18.0-12-generic root=UUID=82e03d14-dda1-416d-910c-6bb973e28ff6 ro quiet splash vt.handoff=1 SourcePackage: xorg UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/15/2018 dmi.bios.vendor: Intel Corp. dmi.bios.version: BECFL357.86A.0051.2018.1015.1513 dmi.board.name: NUC8BEB dmi.board.vendor: Intel Corporation dmi.board.version: J72692-303 dmi.chassis.type: 3 dmi.chassis.vendor: Intel Corporation dmi.chassis.version: 2.0 dmi.modalias: dmi:bvnIntelCorp.:bvrBECFL357.86A.0051.2018.1015.1513:bd10/15/2018:svnIntel(R)ClientSystems:pnNUC8i5BEH:pvrJ72747-302:rvnIntelCorporation:rnNUC8BEB:rvrJ72692-303:cvnIntelCorporation:ct3:cvr2.0: dmi.product.family: Intel NUC dmi.product.name: NUC8i5BEH dmi.product.sku: BOXNUC8i5BEH dmi.product.version: J72747-302 dmi.sys.vendor: Intel(R) Client Systems version.compiz: compiz N/A version.libdrm2: libdrm2 2.4.95-1 version.libgl1-mesa-dri: libgl1-mesa-dri 18.2.2-0ubuntu1 version.libgl1-mesa-glx: libgl1-mesa-glx N/A version.xserver-xorg-core: xserver-xorg-core 2:1.20.1-3ubuntu2.1 version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.1.0-1 version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1ubuntu1 version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-3 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1808653/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
