Installed Lubuntu Mantic and Noble are flaky with two screens

[sudodus]

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
ProcVersionSignature: Ubuntu 6.5.0-10.10-generic 6.5.3
Uname: Linux 6.5.0-10-generic x86_64
ApportVersion: 2.27.0-0ubuntu5
Architecture: amd64
CasperMD5CheckResult: unknown
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)

[Simon Quigley (tsimonq2)]

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!

[sudodus (nio-wiklund)]

@ Simon,

Thanks for the advice.

So far I have *only* tested this in an installed Lubuntu 23.10 (as I tried to describe in the title), so yes, it happens in an installed system.

[sudodus (nio-wiklund)]

Lubuntu Noble installed:

I have Lubuntu Noble installed in my Toshiba Satellite Pro C850-19W with a generation 3 Intel i5 CPU (and built-in Intel graphics) and resolution 1366x768. This system works well when run with only the internal screen and I updated && upgraded it before trying with the external screen (Samsung 1920x1080 via HDMI).

1. Booting when the external screen is connected: Nothing is ever seen, not even an underscore. It does not even react on ctrl+alt+delete. But there is no battery, so turning off power works.

2. Booting with only the internal screen, and connecting the external screen when logged in: It works as it should work.

3. Booting with the external screen connected but turned off: Nothing is ever seen, not even an underscore. This is worse than Lubuntu 23.10 in the HP Probook 640 G4, which could manage this setting repeatedly.

4. Booting with only the internal screen, and connecting the external screen at the login screen: The external screen remained black even after logging in.

5. Booting with only the internal screen, and connecting the external screen when logged in: It works as it should work (the same as test #2).

[sudodus (nio-wiklund)]

I should mention that

- Lubuntu 23.10 is booted in the HP Probook in UEFI mode with secure boot
- Lubuntu Noble is booted in the Toshiba in BIOS mode

and I will tag also Noble as affected by this bug.

[sudodus (nio-wiklund)]

1. I edited grub in Lubuntu Noble installed in my Toshiba: to get an extra menuentry with 'nosplash' instead of 'quiet splash'. It did not help much, because I could not even see the grub menu, when connected to the external screen.

2. I cold-booted with the external screen disconnected, selected the menuentry with 'nosplash', connected the external screen pressed Enter and it worked. Text was scrolling on both screens, and I could even log in on the external screen. So in this case, the problem started already at grub and never recovered, but when connected after that, things worked well.

3. I cold-booted with the external screen disconnected, selected the default menuentry with 'quiet splash', connected the external screen pressed Enter and it worked. I could even log in on the external screen. So in this case, the problem started already at grub and never recovered, but when connected after that, things worked well.

4. I rebooted with the external screen disconnected, selected the default menuentry with 'quiet splash', connected the external screen pressed Enter and it worked. I could even log in on the external screen. So in this case, the problem started already at grub and never recovered, but when connected after that, things worked well.

-o-

These results makes me think that we should blame the fancy semi-graphical grub menu, at least when running Lubuntu Noble in the Toshiba. Maybe there is some race condition, when deciding where to send the graphics or what resolution to use.

Grub is seen when booting the HP Probook, so there must be a problem also later in the boot process.

-o-

Next I intend to connect the internal drive (a SATA SSD) via a USB to SATA adapter and boot different computers from the same Noble system. (I think it is most important to debug the developing LTS version.)

[sudodus (nio-wiklund)]

Lubuntu Noble Installed:

I tested Lubuntu Noble installed in my SSD in a Dell Latitude E7240 with an Intel i5 4200 CPU and Intel Haswell-ULT (built-in) graphics and and resolution 1920x1080, the same as the resolution of the external Samsung screen. The external screen was connected via an HDMI to HDMI cable.

1,2. I cold-booted via F12 and the temporary menu (in BIOS mode) with the external screen connected and turned on. I could see the grub menu and the whole boot process worked. Both screens work. (No need to try 'nosplash'.)

3. I rebooted via F12 and the temporary menu (in BIOS mode) with the external screen connected and turned on. I could see the grub menu and the whole boot process worked. Both screens work.

-o-

Maybe things work better when the screens have the same resolution.

-o-

1,2. Next I tested (cold-booted) Lubuntu Noble installed in my SSD in a Dell Precision M4800 with an Intel i7 4810MQ CPU and nvidia Quadro K1100M graphics using the nouveau driver (plus built-in Intel 4th gen core GPU) and resolution 1920x1080, the same as the resolution of the external Samsung screen. The external screen was connected via an HDMI to HDMI cable, but with a DP to HDMI adapter.

The internal screen worked as expected but nothing could be seen in the external drive. At shutdown a splash screen was seen quickly.

3. I cold-booted with the external monitor disconnected, logged in and then connected the external monitor, and things worked as expected.

Ubuntu Desktop Jammy Installed:

4. I have used this computer with its internal Ubuntu Desktop focal and jammy (now 22.04.3 LTS) systems with my TV as external screen, and it has worked as expected, so now I will try the internal Ubuntu Desktop jammy system: The internal screen works as expected, but I cannot get anything at all on the external screen.

Later today I have to move to the living room and the TV. Has an update && upgrade ruined the ability of the jammy systems ability to use an external screen, or is the connection via the DP to HDMI adapter problematic or is this external screen difficult to use? I noticed, that only the Intel graphics worked. The nouveau driver was not accepted, which (if I remember correctly) it was with earlier versions of Ubuntu jammy, when I watched movies via this computer and the TV screen. The current jammy kernel is 6.2.0-39-generic.

Ubuntu Desktop 23.04 Live

5,6. I cold-booted Ubuntu Desktop 23.04 live booted 'grub-n-iso', and it worked as expected with both internal and external screens connected.

Lubuntu 23.10 Live:

7. I cold-booted Lubuntu 23.10 live booted 'grub-n-iso' with the external screen connected and turned on. The internal screen worked but the external screen was black. Here I saw that nouveau was used for the nvidia chip.

8. I cold-booted Lubuntu 23.10 live booted 'grub-n-iso' with the external screen connected but turned off. The internal screen worked but the external screen was black. It did not wake up, when turned on when booted to the desktop.

9,10,11. I cold-booted Lubuntu 23.10 live booted 'grub-n-iso' with the external screen disconnected, and connected it after the system had reached the desktop. Now there was a correct ...

[Simon Quigley (tsimonq2)]

I'm going to take a chance here and say that this is a GRUB bug. I'm marking the appropriate targets for that.

Friendly neighborhood GRUB folks, does this sound like a GRUB bug to you?

[sudodus (nio-wiklund)]

It made no difference with the Dell Precision M4800 at the TV (which has also the resolution 1920x1080) with a clean cable (without an adapter) compared to the previous tests. In other words, next time I want to watch a movie on the TV via the internet, I have to find an alternative, Ubuntu Jammy can no longer do it in that computer. And there are alternatives, at least when the external screen (TV) is connected when logged in (or live booted all the way to the desktop).

-o-

Then I tested in a *Dell Latitude 3520* with an Intel i3 1115G4 (gen 11) CPU and an Intel Device 9a78 GPU (built-in) and screen resolution 1920x1080 with *Ubuntu Desktop 22.04.3 LTS* installed and updated && upgraded today.

1,2,3,4. I booted in UEFI mode with secure boot, when the external Samsung screen is connected (via HDMI to HDMI cable). From grub until and including the login screen only the internal screen showed what is happening, but *after login the external screen worked as expected*. (The second and third time, the splash screen is shown briefly on both screens, but the login screen is shown only on the internal screen.)

So this seems to be a stable alternative to watch a movie on the TV via the internet :-)

[sudodus (nio-wiklund)]

I tested Ubuntu Desktop Noble live in the Dell Precision M4800 (with nvidia), where there are problems with the current Jammy version.

1,2,3,4. I booted in BIOS mode, when the external Samsung screen was connected. The grub menu was only shown on the internal screen but starting with the splash the external screen worked as expected.

It seems stable, so there is something specifically wrong with the Lubuntu Noble flavour.

[sudodus (nio-wiklund)]

Now Ubuntu Desktop Noble live was 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 external screen is connected via HDMI (a HDMI to HDMI cable). This is the same setup as in the original bug report except that Ubuntu Desktop was tested instead of Lubuntu.

1,2,3. I booted in UEFI mode with secure boot, when the external Samsung screen was connected. The grub menu was only shown on the internal screen but starting with the splash the external screen worked as expected.

This test confirms that standard Ubuntu Desktop Noble works while Lubuntu Noble is flaky in some laptops when an external screen is connected.

[Simon Quigley (tsimonq2)]

Can we also try Kubuntu to narrow this down further, if it isn't too much to ask?

[sudodus (nio-wiklund)]

Kubuntu Noble live:

I tried Kubuntu Noble in my Toshiba Satellite Pro C850-19W with a generation 3 Intel i5 CPU (and built-in Intel graphics) and resolution 1366x768. This system works well when run with only the internal screen and I updated && upgraded it before trying with the external screen (Samsung 1920x1080 via HDMI).

1. Booting in BIOS mode when the external screen is connected: Nothing is ever seen, not even an underscore. It does not even react on ctrl+alt+delete.

2. Booting when the external screen is disconnected: it works as expected. I selected 'Try Kubuntu' and reached the desktop. Then I connected the external screen, and it works as expected.

3,4. Booting when the external screen is disconnected. At the grub menu I connected the external screen and hit enter to start the default 'Try or Install Kubuntu'. For a while there is only text on the internal screen, then splash on both screens and then both screens show the desktop. The window with 'Try' and 'Install' is on the external screen, but can be dragged to the internal one, in other words, it works as expected.

-o-

So this indicates that there is a problem to show the grub menu, and it never recovers, if the external screen is connected at boot.

-o-

I installed Kubuntu (into an SSD in the Toshiba), a basic installation using the whole drive.

Anyway, Kubuntu Noble has a basic text mode grub menu (like Ubuntu Desktop), not a fancy semi-graphical one like Lubuntu Noble. So we cannot blame that, but still, the bug appears already at grub.

Kubuntu Noble installed:

1. I rebooted when Calamares had finished. The external screen was connected, and everything was black (as expected, like the live case).

2. I turned off the power (brutal shutdown), disconnected the external screen, and cold booted. There is no grub menu (as expected). At the login screen I connected the external screen. Nothing happened, but after log in the desktop was shown in both screens, and it works as expected and I can configure the two screens, things work.

3. I shutdown gracefully, disconnected the external screen, and cold booted. There is no grub menu (as expected). At the login screen I connected the external screen. Nothing happened, but after log in the desktop was shown in both screens, and things work.

-o-

The bug is affecting the installed Kubuntu Noble system too.

-o-

Kubuntu Noble live again:

Now Kubuntu Noble live was tested in the HP Probook 640 G4 connected to the old Samsung monitor with 1920x1080 resolution. The external screen is connected via HDMI (a HDMI to HDMI cable). This is the same setup as in the original bug report except that Kubuntu was tested instead of Lubuntu.

1,2,3. Cold-booting in UEFI mode with secure boot when the external screen is connected: The grub menu is seen in the internal screen. I selected the default 'Try Kubuntu'. The splash screen is seen in both screens and the desktop is seen in both desktops. It works. Is it flaky? I will test a few times ...

4,5. Rebooting in UEFI mode with secure boot when the external screen is connected: The grub menu is seen in the internal screen. I selected the default 'Try Kubuntu'. The splash screen is seen in ...

[sudodus (nio-wiklund)]

New daily iso file:

Toshiba Satellite Pro C850-19W with an external screen connected (in BIOS mode): The installation is finished, but the installed system does not work, when booted with an external screen connected. Nothing is shown in any of the screens.

When booted with the external screen disconnected, things work, and the external screen can be connected and things work as they should.

I edited grub and could see the semi-graphical grub menu at the next boot. So probably the same method, that fixed booting the live session, should fix the installed session :-P

[sudodus (nio-wiklund)]

New daily iso file:

Toshiba Satellite Pro C850-19W

1. booted BIOS mode. Installation works with 2 screens, but the computer can only boot from the internal drive, when the external screen is disconnected. After booting (and something is shown on the internal screen), the external screen can be connected and things work correctly: The same result as with the previous daily iso file.

2. Booted in UEFI mode. Installed Lubuntu (in UEFI mode). Now things seems to work as expected after reboot and cold-boot into the installed system.

-o-

So this bug affects this old Toshiba only in BIOS mode.

[sudodus (nio-wiklund)]

Further testing the Lubuntu Noble system that was *installed in an SSD* in the Toshiba, but now connected via a USB to SATA adapter:

1. It boots correctly (in BIOS mode) in an HP Probook 6450b with an Intel i5 M 520 CPU with built-in graphics, also when the external screen is connected at boot. The graphics work correctly in both screens, when logged in - - first time test, this in an older Probook than the one where the bug was originally found.

2. It boots correctly (in BIOS mode) in a Dell Latitude E7240 with an Intel i5 4200 CPU with built-in Intel Haswell-ULT graphics, also when the external screen is connected at boot. The graphics work correctly in both screens, when logged in -- worked also before, just a second check.

3. It boots correctly (in BIOS mode) in a Dell Precision M4800 with an Intel i7 4810MQ CPU with built-in Intel graphics and nvidia Quadro K1100M GPU, also when the external screen is connected at boot. The graphics works correctly in the internal screen. However, in order to make the external screen work, it must be connected after login. -- tested before in this bug report. Now the nouveau graphics driver is active for the nvidia chip, and even when connected at boot xrandr shows that the external screen is connected, but it is still black unless disconnected and then connected after login. I think the problem with this computer can be blamed (at least partly) on the nvidia driver.

[sudodus (nio-wiklund)]

After today's tests I think I understand more about the buggy behaviour in the Toshiba Satellite Pro C850-19W, when two screens are connected, the internal one plus an external screen via HDMI.

I tested the installed Lubuntu Noble system when the SSD was connected via a USB to SATA adapter. And it worked as it should all the way, also when the external screen was connected all the time including cold-boot and reboot.

I did some more tests this time by putting various SSDs inside the Toshiba, with a cloned live Lubuntu Noble system (standard with grub 2.12~rc), and a persistent live Lubuntu Noble system and an installed Ubuntu Server Kinetic (with grub 2.0.6). And it seems that whatever operating system is in the internal drive, it will not even get to the grub menu in BIOS mode, when the external screen in connected.

-o-

I should have tested this earlier, anyway now I think that there is a bug in the UEFI/BIOS system of the Toshiba, not a bug in grub or Ubuntu.

However, the original problem exists, that causes the flaky behaviour in UEFI mode in the HP Probook 640 G4. So I will re-focus on that problem and see if things can be made stable (repeatable).

[sudodus (nio-wiklund)]

Lubuntu 23.10 installed:

I tested Lubuntu 23.10 which is installed in UEFI mode in the HP Probook 640 G4 (internal ). This matches what was described in the original bug report.

1-3. Cold-booted with the external screen connected all the time. It worked well.

4. Rebooted with the external screen connected all the time. It worked well.

-o-

I updated && upgraded Lubuntu.

5. Cold-booted with the external screen connected all the time. It worked well.

6. Rebooted with the external screen connected all the time. It worked well.

-o-

Why are things working better now?

a. Maybe the file system or some memory locations was corrupted after the previous testing and brutal shutdowns between various attempts with Lubuntu Noble live before testing the installed system.

b. Maybe the power voltage was a bit low. I had not used the computer recently, and I was/am charging it via USB-C.

c. Maybe the HDMI connection was a bit oxidized and flaky. After plugging and replugging several times, the connection might be cleaned from oxides.

Lubuntu Noble Live:

7. I plugged in Lubuntu Noble live via USB, made by cloning, and had a glitch (nothing on any of the screens except a white underscore on the internal screen). I disconnected the external screen, the system recovered, and I could connect the external screen again and things worked.

d. I suspect that I pressed F9 for a temporary menu too late, and caused the glitch. Maybe this caused some of the original glitches too.

8,9. Cold-booted with the external screen connected all the time. It worked well after alt+tab.

10. Rebooted with the external screen connected all the time. It worked well after alt+tab.

11,12. I plugged in Lubuntu Noble persistent live via USB, made by dus-iso2usb (grub-n-iso method). It worked well too after alt+tab.

-o-

So, things look more consistent (less flaky) now, at least partly because I can repeat the tests in a more consistent way.

[sudodus (nio-wiklund)]

@ Simon,

I no longer think the problems described in this bug report can be blamed on any component of any Ubuntu flavour. So maybe change the status to invalid?

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/2047456