Screen resolution on external monitor won't go above 2560 x 1080

[Matt White]

I have an external monitor capable of 3440 x 1440. I am using a Thinkpad T480s. Up until about 2 weeks ago, I could set the resolution of the monitor to 3440 x 1440 just fine. Now when I try, the screen goes black and I have to revert to a lower resolution. The highest it will go now is 2560 x 1080. Lower resolutions work fine as well.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xorg 1:7.7+19ubuntu7.1
ProcVersionSignature: Ubuntu 5.0.0-23.24~18.04.1-generic 5.0.15
Uname: Linux 5.0.0-23-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.9-0ubuntu7.7
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Mon Aug 12 08:56:25 2019
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
DkmsStatus:
 acpi-call, 1.1.0, 4.18.0-25-generic, x86_64: installed
 acpi-call, 1.1.0, 5.0.0-23-generic, x86_64: installed
ExtraDebuggingInterest: Yes, including running git bisection searches
GraphicsCard:
 Intel Corporation UHD Graphics 620 [8086:5917] (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Lenovo UHD Graphics 620 [17aa:2258]
InstallationDate: Installed on 2019-02-19 (173 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
MachineType: LENOVO 20L7S01200
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.0.0-23-generic root=UUID=471b6634-e334-44c7-b898-080ab93327e0 ro quiet splash vt.handoff=1
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/19/2019
dmi.bios.vendor: LENOVO
dmi.bios.version: N22ET53W (1.30 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20L7S01200
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:bvrN22ET53W(1.30):bd02/19/2019:svnLENOVO:pn20L7S01200:pvrThinkPadT480s:rvnLENOVO:rn20L7S01200:rvrSDK0J40709WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad T480s
dmi.product.name: 20L7S01200
dmi.product.sku: LENOVO_MT_20L7_BU_Think_FM_ThinkPad T480s
dmi.product.version: ThinkPad T480s
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.13.1+18.04.20180302-0ubuntu1
version.libdrm2: libdrm2 2.4.97-1ubuntu1~18.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 19.0.2-1ubuntu1.1~18.04.2
version.libgl1-mesa-glx: libgl1-mesa-glx 19.0.2-1ubuntu1.1~18.04.2
version.xserver-xorg-core: xserver-xorg-core N/A
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Kai-Heng Feng (kaihengfeng)]

Please test latest mainline kernel:
https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.3-rc4/

[Matt White (mattw922)]

I tried both 5.2.11 and 5.3-rc6. Same result with both.

[Kai-Heng Feng (kaihengfeng)]

OK, can you please find the last working version?

[Matt White (mattw922)]

I went back pretty far, into the 4.x versions, and still had the same results, so I'm guessing this isn't kernel-related. Any suggestion on what else to try?

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.