Public bug reported:
I have a Thinkpad P1 Gen 2. This specific machine was customized to NOT
have a discrete Nvidia GPU. It ONLY has an integrated Intel UHD 630 GPU.
This is not a hardware issue as Windows seems to handle things
correctly.
With an external monitor connected via HDMI, boot proceeds OK with the
external monitor displaying the boot process.
I log in to a Gnome session using X.
After login, I am able to open the display settings GUI and set mode to
"single display" with the built-in LCD disabled and the external monitor
enabled. This works correctly.
However, if I then reboot the machine with the external monitor
connected:
1. Boot proceeds correctly with the boot process shown on the external
monitor.
2. After login, the external monitor is powered off and the built-in LCD
is enabled. The "display settings" GUI shows the external monitor as a
connected "Unknown Display" with the wrong resolution of 1024x768.
Attempting to use the GUI to set "single display" as above results in
the external monitor still being powered off, and the built-in LCD also
powered off. I have to press esc to cancel the display changes.
At this point, the relevant output of `xrandr` is:
````
DP1 connected 1024x768+3840+0 (normal left inverted right x axis y axis) 600mm
x 340mm
1024x768 60.00*
800x600 60.32 56.25
848x480 60.00
640x480 59.94
````
DP1 is the HDMI output, and it is listed at the wrong resolutions.
If I disconnect the HDMI cable then run `xrandr` again, the output of
`xrandr` is unchanged: it still lists DP1 as connected (!) even though
the cable is disconnected.
This bug also occurs if instead of rebooting, I simply log out and log
back in again.
The only solution appears to be to unplug the HDMI cable, shut down the
machine (not reboot or log out), power on, log in, and at the desktop
plug in the HDMI cable. At that point it works again.
Rebooting does not solve the issue. It seems that a complete shutdown is
required.
I tested on Ubuntu 20.04's stock kernel 5.4.0 and also kernel 5.7.7 and
the issue is present on both versions.
ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.4.0-40-generic 5.4.0-40.44
ProcVersionSignature: Ubuntu 5.4.0-40.44-generic 5.4.44
Uname: Linux 5.4.0-40-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.3
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: alex 1888 F.... pulseaudio
CasperMD5CheckResult: skip
CurrentDesktop: GNOME
Date: Fri Jul 3 16:00:55 2020
InstallationDate: Installed on 2020-07-03 (0 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
MachineType: LENOVO 20QTCTO1WW
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/usr/bin/zsh
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-40-generic
root=UUID=f8b7e5a7-d866-4a48-aef0-b430465ab66d ro quiet splash vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-5.4.0-40-generic N/A
linux-backports-modules-5.4.0-40-generic N/A
linux-firmware 1.187.1
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/20/2020
dmi.bios.vendor: LENOVO
dmi.bios.version: N2OET42W (1.29 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20QTCTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: SDK0R32862 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias:
dmi:bvnLENOVO:bvrN2OET42W(1.29):bd01/20/2020:svnLENOVO:pn20QTCTO1WW:pvrThinkPadP1Gen2:rvnLENOVO:rn20QTCTO1WW:rvrSDK0R32862WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad P1 Gen 2
dmi.product.name: 20QTCTO1WW
dmi.product.sku: LENOVO_MT_20QT_BU_Think_FM_ThinkPad P1 Gen 2
dmi.product.version: ThinkPad P1 Gen 2
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug focal
** Attachment added: "xrandr-broken"
https://bugs.launchpad.net/bugs/1886230/+attachment/5389496/+files/xrandr-broken
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https://bugs.launchpad.net/bugs/1886230
Title:
Thinkpad P1 Gen2 HDMI doesn't work after log out or reboot
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