Screen flickers a few times in X11

[lakshayrohila]

I am using Kubuntu 24.04 Plasma 5.27.11 (X11). I upgraded from 23.10 to 24.04 yesterday only and have experienced screen flickering issues (by flickering, I mean turning on-off very quickly) 4-5 times already. The screen would flicker for not more than a few seconds though (maybe till I move my cursor).

I used to have this problem in wayland earlier. Never had this problem with 23.10 or 23.04 in X11.

Although, this is not a big problem, I thought it might be worth opening a topic about.

Please ask about any additional details required.

Thanks!

[Schwarzer Kater]

Welcome.

Did you check if this also occurs in a new user account?

And are you sure you are using X11 in Kubuntu 24.04 LTS?
You can check this e.g. in the Info Center.

Otherwise see https://www.kubuntuforums.net/forum/...805#post679805.

The more details you can give (hardware, software, your specific set-up, what you have done step-by-step, etc.) the better the chances are that somebody can help you…

[lakshayrohila]

Welcome.

Did you check if this also occurs in a new user account?

And are you sure you are using X11 in Kubuntu 24.04 LTS?
You can check this e.g. in the Info Center.

Otherwise see https://www.kubuntuforums.net/forum/...805#post679805.

The more details you can give (hardware, software, your specific set-up, what you have done step-by-step, etc.) the better the chances are that somebody can help you…

Thanks for your reply. I checked the info center, I am sure it is Kubuntu 24.04 LTS with X11.

All of my setup remains same as was earlier, although this issue started to occur only after the upgrade. Although, I find this very random.

Here are some details about my system:


An additional detail I forgot to mention: I at some point of time (before the update to Kubuntu 24.04), had tried reinstalling libgl* and libegl* libraries through apt (which seems to have caused some problem), as I thought the reason for my Firefox crashing was that package. After reinstallation, apt version of firefox even refused to create webgl context, as I had earlier opened this issue on Mozilla support: https://support.mozilla.org/en-US/questions/1445711. Now, I can understand why it happened, as I seem to have messed up some of my WebGL (EGL) related config by that reinstallation:

Can this be the cause of the flickering issue? As I mentioned earlier, this EGL problem occured well before I upgraded Kubuntu, and then the flickering issue was not there.

Please ask if more details are required. Thanks!

[lakshayrohila]

Running the `eglinfo` command in terminal, it segfaults:



Other thing I noticed is that when I tried to not move my cursor, the screen kept on flickering until I moved my cursor.

[Schwarzer Kater]

OK, I quickly read through your post on Mozilla.org - I don't know if this will help you in any way, but here is what I would do.

You seem to have already been working on these problems for some time now without success and - at least for me - it is not quite clear what you could have made worse by e.g. the things you posted on Mozilla.org.
So: I would back up the (user) data, format the partitions I want to install Kubuntu 24.04 LTS to, install Kubuntu 24.04 LTS from scratch, do those things afterwards:
Essential and strongly recommended things to do directly after a Kubuntu 24.04 LTS installation
and copy back my data.
Then I would install the programs I want to use and set up the system to my liking.
For one of my own systems that would take approximately 60 to 90 minutes (I have done those things many times and everything is properly documented) - perhaps it will take two or three hours for you at the most. I bet you have already spent more time for solving the things you posted on Mozilla.org and here.

This way you would exclude anything from your interventions that could have caused your problems and it will also exclude any errors that could (additionally) have snuck in by the release-upgrade from 23.10 to 24.04 LTS (or a possible release-upgrade from 23.04 to 23.10 before).
I think that there is a good chance that the things will work afterwards - good luck. Otherwise you will at least have excluded two major unknown factors for your problem solving…


PS: Which "apt version" of Firefox did you use in 23.10 (you mentioned this on Mozilla.org)? Because there is no "apt version" in the *Ubuntu repositories for 23.10 (and not for every *Ubuntu since 22.04 LTS), but a "fake" Firefox package that will sneakily install the Firefox Snap instead.
Or did you add the official external Firefox repository?
Or did you install the Firefox .tar to /opt (as the install traditional Firefox script does)?

[lakshayrohila]

Thanks for the suggestion! I also was thinking of reinstallation, although I think I will schedule that for some time later since the flickering problem doesn't create much nuisance to me (except for sometimes scaring me ). About the firefox problem, I do not remember how I got hold on that version of firefox. As far as I remember, I had removed the snap version and somehow installed the apt version. Then I went to the flatpak version and the problem was fixed. Now, after the Kubuntu update, I am back to snap version and the wegbl problem does not exist, just like in the flatpak version. (So, I am not really bothered about that issue right now .)

Again, thanks for the suggestion though! I will definitely reinstall, but feel too lazy to do it right now.