Comment 18 for bug 2047456

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.