Primary screen missing bottom bar since today


I have a two monitor setup. Both monitors are the same (make, model, resolution, frequency), and my desktop uses the left monitor as a primary (with the bottom KDE bar), and the right monitor extends the left. I did updates this morning, these packages (from /var/log/pacman.log):

[2021-11-23T07:22:30+0100] [ALPM] upgraded fluidsynth (2.2.3-1 -> 2.2.4-1)
[2021-11-23T07:22:30+0100] [ALPM] upgraded imagemagick ( ->
[2021-11-23T07:22:30+0100] [ALPM] upgraded kimageannotator (0.5.2-1 -> 0.5.3-1)
[2021-11-23T07:22:31+0100] [ALPM] upgraded libimagequant (2.16.0-1 -> 2.17.0-1)
[2021-11-23T07:22:31+0100] [ALPM] upgraded linux (5.15.3.arch1-1 -> 5.15.4.arch1-1)
[2021-11-23T07:22:32+0100] [ALPM] upgraded linux-headers (5.15.3.arch1-1 -> 5.15.4.arch1-1)
[2021-11-23T07:22:33+0100] [ALPM] upgraded nvidia (495.44-11 -> 495.44-12)
[2021-11-23T07:22:33+0100] [ALPM] upgraded python-fonttools (4.28.0-1 -> 4.28.1-1)
[2021-11-23T07:22:33+0100] [ALPM] upgraded python-mako (1.1.5-1 -> 1.1.6-1)
[2021-11-23T07:22:33+0100] [ALPM] upgraded r8168 (8.049.02-37 -> 8.049.02-38)
[2021-11-23T07:22:34+0100] [ALPM] upgraded wine-staging (6.21-3 -> 6.22-1)
[2021-11-23T07:22:34+0100] [ALPM] upgraded wine-mono (6.4.0-1 -> 7.0.0-1)

Somehow, after rebooting, my left monitor doesn’t have a bottom bar anymore, the bar moved to the right monitor. However, the left monitor is still the primary monitor. The bottom bar is now on the non-primary monitor. The strangest thing is, when I stop using the right monitor to extend the left (for instance, let the right monitor be a copy of the left monitor), then no monitor has a bottom bar.

I can switch them around all I want, I cannot get the left monitor to be the primary monitor and have a bottom bar. All games suddenly start on the right monitor, while they usually start on the left one.

I’m not sure how to proceed. I can go back to a previous snapshot and try to update in a week, hoping that the problem is fixed by then, but I’d rather hear if somebody has an idea. As there were no KDE packages updated today (with the exception of kimageannotator, which doesn’t sound relevant), I don’t see which package could have created this strange behaviour.

try to set right one as primary and log-out-back-in if bar is still on right monitor set the left one as primary log-out-back-in and see if it is working again…

Done and done. Sadly, nothing changes, both starts show the behaviour described in my original post. 2 things might be noteworthy:

  1. The login screen is now firmly on the right monitor. That happened sometimes, but now it seems to be consistent.
  2. When changing the display settings (“Anzeige und Monitor”, “Display and monitor” in KDE settings), after changing the primary, clicking “Anwenden” (“Apply”), then logging out, the settings dialog asks me if I want to keep the changes or discard them.

it could be SDDM is the culprit… possible to set the displays already for sddm:


Path of script to execute when starting the display server. Default value is “/usr/share/sddm/scripts/Xsetup”.

Afaik you can use an xrandr script there.

I do not really see any solution using an sddm script. The problem remains that I cannot make my left monitor primary (as in, applications and games naturally get started on it) without also having my taskbar on the right monitor.

What I have done now is set everything up so that the taskbar is on the left monitor again, and the right monitor expands the left one, however, that means that the right monitor needs to be primary, and new applications and fullscreen games start on it.

Its not pretty, but it works for the time being.

Did you try downgrading to kernel stable or/and downgrading Nvidia driver?
I don’t think it’s a KDE/Plasma issue. I assume it’s a mixture of Nvidia and kernel issue.

sddm using also your two displays and it is using the same system … so it could mess with the settings for your displays.

I have two displays setup and i see that the left display is always set to primary on bootup. independent from DM/DE/WM i am using. This depends on the GPU connectors themself. left monitor is plugged on DVI and right one on HDMI… p.e.

And if i do not set up displays for DM to the same i use inside DE/WM it will screw my settings.

But on my plasma install, i can not replicate your issue.
On first login the left display was automatically set to primary, holding the panel, after simply changing the right one to be primary panes switched to the right display and stays there over reboots.
I do not setup anything for sddm.

So, today when I started my machine the strangest thing happened. I did not have a bottom bar at all. I vaguely remember that I had this problem before. I googled it and read this link (which was already read, so I knew I googled that before).

Moving the plasma-org.kde.plasma.desktop-appletsrc file and restarting recreated it. Comparing the original and the new one shows differences, and with the recreated file the normal behaviour and bottom bar are back, the primary screen has the bottom bar, all is well.

Thank you for your help.

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