Installed Lubuntu Mantic and Noble are flaky with two screens
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
grub2 (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
lxqt-session (Ubuntu) |
Invalid
|
Undecided
|
Unassigned |
Bug Description
Tested in an HP Probook 640 G4 with
- Intel i5-8250U CPU
- Intel 'UHD Graphics 6'
- built-in resolution 1366x768
connected to an old Samsung monitor with 1920x1080 resolution. The extermal screen is connected via HDMI (a HDMI to HDMI cable).
It works smoothly when booted as usual (with only the internal screen). After testing Lubuntu Noble live, when booting with the external screen connected, it failed to show anything (nothing on any of the screens except a white underscore on the internal screen). Alt+tab did not help.
I rebooted brutally with ctrl+alt+delete, disconnected the external screen and things worked well. When logged in, I cnnnected the external screen, and then things worked as expected. I had the correct background and could use both screens. So in order to check if it was a temporary glitch, I rebooted and cold booted several times:
1. I prepared for making a separate bug report for problems with 2 screens in Lubuntu 23.10. And it worked, when cold booted, also when the external screen is connected. Maybe some bad state in some electronic component(s) of the system was not cleared by the brutal reboot (ctrl+alt+delete) after the failure with Lubuntu Noble live.
I repeated reboot and cold boot a few times to see if things continue to work well.
2. It worked again after reboot
3. It failed like the first time after 'correct shutdown via the menu' and cold boot after a few seconds.
4. It worked well after brutal reboot (ctrl+alt+delete).
5. It failed like the first time after 'correct shutdown via the menu' and cold boot after one minute (so 'colder' than the previous cold boot).
6. It worked well when cold booted with the external monitor connected but turned off.
7. It worked well when cold booted with the external monitor connected but turned off (again), When logged in, I turned on the extermal screen and it showed what it should show.
8. It worked well when cold booted with the external monitor connected but turned off (again), When logged in, I turned on the extermal screen and it showed what it should show.
9,10. It failed when I tried to edit the grub menu with 'e'. It booted without any command to boot (and it happened twice).
11. It kind of worked, when I booted in recovery mode, but only the internal screen was active.
12. It worked well when cold booted into normal mode with the external screenconnected and turned on.
13. It worked well when cold booted with the external monitor connected but turned off, When logged in, I turned on the extermal screen and it showed what it should show.
So I would say that the function is flaky with two screens connected and the external one turned on at boot.
-o-
Please notice that the system works now, with both screens. I am not able to create a bug report when it fails, because there is only an underscore on the internal screen and nothing on the external one.
Please advice how to create a useful log file to upload (for example by booting without 'quiet splash', and what log file should I look for and upload)!
ProblemType: Bug
DistroRelease: Ubuntu 23.10
Package: lxqt-session 1.3.0-0ubuntu4
ProcVersionSign
Uname: Linux 6.5.0-10-generic x86_64
ApportVersion: 2.27.0-0ubuntu5
Architecture: amd64
CasperMD5CheckR
CurrentDesktop: LXQt
Date: Tue Dec 26 21:17:14 2023
InstallationDate: Installed on 2023-10-21 (66 days ago)
InstallationMedia: Lubuntu 23.10 "Mantic Minotaur" - Release amd64 (20231010)
SourcePackage: lxqt-session
UpgradeStatus: No upgrade log present (probably fresh install)
summary: |
- Installed Lubuntu Mantic is flaky with two screens + Installed Lubuntu Mantic and Noble are flaky with two screens |
Changed in grub2 (Ubuntu): | |
status: | New → Invalid |
Changed in lxqt-session (Ubuntu): | |
status: | New → Invalid |
My first idea is, maybe look to see if this happens on an installed system. If you can, in fact reproduce this, the next step would be to look for kernel logs. If you try booting *without* quiet, and by replacing splash with nosplash, if you don't see *anything* related to systemd units, it's a kernel issue. I don't really work with kernel packages that often, so as for the relevant logs, your guess is as good as mine (and I'm hoping the kernel team has some good documentation).
If it is not at all reproducible with a new install, I'd say the next step is to check other flavors and releases. This could be something that affects all flavors for 23.10, or just us. It could be something with the version, it could be something that affects 22.04 or 24.04 as well. There's a lot that's not certain yet, but let me be clear: verbosity is key here. I'm happy to review full syslogs and full systemd journals. I can certainly *try* reading kernel logs, and I know C/C++ so it's not impossible, but I *definitely* don't have the permissions or confidence to unilaterally deliver a fix.
Thanks in advance for your help!