External monitor undetected over hdmi

[Rhys Davies]

After the latest updates when I plug in an external monitor over HDMI it doesn't pick it up. Unplugging and re-plugging the monitor seems to connect but immediately drops into power-saving mode.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.4.0-54-generic 5.4.0-54.60
ProcVersionSignature: Ubuntu 5.4.0-54.60-generic 5.4.65
Uname: Linux 5.4.0-54-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.12
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: rhys 6253 F.... pulseaudio
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Thu Nov 19 20:07:19 2020
InstallationDate: Installed on 2019-10-12 (404 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
MachineType: LENOVO 20KH007BUK
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-54-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-5.4.0-54-generic N/A
 linux-backports-modules-5.4.0-54-generic N/A
 linux-firmware 1.187.4
SourcePackage: linux
UpgradeStatus: Upgraded to focal on 2020-09-02 (78 days ago)
dmi.bios.date: 02/20/2020
dmi.bios.vendor: LENOVO
dmi.bios.version: N23ET71W (1.46 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20KH007BUK
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:bvrN23ET71W(1.46):bd02/20/2020:svnLENOVO:pn20KH007BUK:pvrThinkPadX1Carbon6th:rvnLENOVO:rn20KH007BUK:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad X1 Carbon 6th
dmi.product.name: 20KH007BUK
dmi.product.sku: LENOVO_MT_20KH_BU_Think_FM_ThinkPad X1 Carbon 6th
dmi.product.version: ThinkPad X1 Carbon 6th
dmi.sys.vendor: LENOVO

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

This change was made by a bot.

[AaronMa (mapengyu)]

Does the monitor work before the udpate?
What kind of monitor?

[Rhys Davies (rhys-davies)]

It did work before the update, it's a Lenovo C-22 10

[Alex Hung (alexhung)]

What is the kernel version before updating? Is it 5.4.0-53 or earlier versions?

[Rhys Davies (rhys-davies)]

I'm not certain but I don't think the update included a major update so it would have been 5.4.0-53 or -54-generic

[Rhys Davies (rhys-davies)]

Any movement on this?

[Kai-Heng Feng (kaihengfeng)]

Please test latest mainline kernel:
https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.10/amd64/

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]