System fallback to gdm login screen when hot-plugging a external monitor in 1st time

[jeremyszu]

[Steps to reproduce]
1. Install Jammy daily build
2. dist-upgrade to verify https://bugs.launchpad.net/mutter/+bug/1964037
3. reboot with no attach monitor
4. attach monitor after booting

[Expect result]
external monitor works directly

[Actual result]
system go back to gdm login screen

[Additional information]
1. the external port is connecting to dGPU.
2. happens on wayland only
3. Only back to login screen in 1st attach, 2nd, 3rd, etc.. works good

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: mutter (not installed)
ProcVersionSignature: Ubuntu 5.15.0-25.25-generic 5.15.30
Uname: Linux 5.15.0-25-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu81
Architecture: amd64
CasperMD5CheckResult: pass
Date: Thu Apr 14 21:22:47 2022
InstallationDate: Installed on 2022-04-13 (0 days ago)
InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" - Daily amd64 (20220409)
SourcePackage: mutter
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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

[Jeremy Bícha (jbicha)]

I feel like I experience the same bug.

- My system has only Intel graphics. No NVIDIA. Only the single GPU.
- Happens in both the Ubuntu [Wayland] and the Ubuntu on Xorg sessions
- I get sent to the login screen the first time I connect an external monitor. Or I get sent to the login screen the first time I disconnect an external monitor that was connected when I started Ubuntu.

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It sounds like some part of the system has crashed. To help us find the cause of the crash please follow these steps:

1. Look in /var/crash for crash files and if found run:
    ubuntu-bug YOURFILE.crash
Then tell us the ID of the newly-created bug.

2. If step 1 failed then look at https://errors.ubuntu.com/user/ID where ID is the content of file /var/lib/whoopsie/whoopsie-id on the machine. Do you find any links to recent problems on that page? If so then please send the links to us.

3. If step 2 also failed then apply the workaround from bug 994921, reboot, reproduce the crash, and retry step 1.

Please take care to avoid attaching .crash files to bugs as we are unable to process them as file attachments. It would also be a security risk for yourself.

[Michael Aaron Murphy (mmstick76)]

Fixed 2 days ago in updated gdm package.

[jeremyszu (os369510)]

Hi Michael,

do you mean the patch to disable wayland on nVidia?

[Daniel van Vugt (vanvugt)]

If there's no crash then please try Ctrl+Alt+F2. I think I saw a similar issue last week where the login screen appeared but I was not logged out. Logging in again returned me to my session but Ctrl+Alt+F2 should achieve the same.

Sounds like gdm3 might be restarting the login screen (another gnome-shell instance) too soon and forcing a VT switch away from the user session.

[Daniel van Vugt (vanvugt)]

Bug 1969097 sounds like it might explain it.

[Daniel van Vugt (vanvugt)]

Please update your system and verify that gdm3 is version >= 42.0-1ubuntu7

Does the bug still occur?

[jeremyszu (os369510)]

after upgrading to 42.0-1ubuntu7 and can not reproduce this issue (default X).
Selected to Wayland can not reproduce this issue as well.