Resolution changes after switching off the monitor

Hello all,

since Plasma 6 Update, my screen resolution always changing to the wrong configuration and Hz if i switch off the monitor.

Normaly i have 5120x1440 with 120Hz. So after switch off and on again, i get 3840x1080 with 100Hz. Yes can switch back to the right resolution but i can’t set the right Hz again. So i have a bad screen. The only way to fix this, is to reboot the whole machine.

Does anyone else have the same problem?

Sounds like something is crashing when you turn the screen off. Can you check with journalctl -f and then turning the screen off and on?

Cannot set is because you cannot select it or because it doesn’t apply the changes?

Are you using displayport or hdmi?

Here is the log: OSIT.CC OpenCloud

I can apply, but 120Hz are gone away from the drop-down menu.

Displayport with an Nvidia graphiscard GTX4090. Driver Version: 545.29.06

This is a 10 year old issue, it has to do with monitors pulling the hotplug pin low when turned off. It’s a feature of DisplayPort. I’m not aware of a driver fix for it. windows 7 - Turning DisplayPort monitor off disables monitor completely - Super User
Sometimes you can workaround that by disabling certain things in your monitor, as outlined in that thread.
As last ditch effort you can use HDMI, but it would be a bit of a downgrade because DP is the better connector.

If this is an 10 years old bug, i wonder why this is only now appearing on Plasma6. Unfortunately I don’t have such an option on the monitor. But I have other error messages. For example, when I try to add a widget to the desktop. Apparently the system then no longer recognises the X/Y axes.

Mär 02 12:58:05 darkbox kwin_x11[5460]: kwin_effect_blur: Failed to create an offscreen framebuffer
Mär 02 12:58:05 darkbox kwin_x11[5460]: kwin_scene_opengl: 0x501: GL_INVALID_VALUE error generated. <levels>, <width> and <height> must be 1 or greater.
Mär 02 12:58:05 darkbox kwin_x11[5460]: kwin_scene_opengl: Invalid framebuffer status:  "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT"
Mär 02 12:58:05 darkbox kwin_x11[5460]: kwin_effect_blur: Failed to create an offscreen framebuffer
Mär 02 12:58:05 darkbox kwin_x11[5460]: kwin_scene_opengl: 0x501: GL_INVALID_VALUE error generated. <levels>, <width> and <height> must be 1 or greater.
Mär 02 12:58:05 darkbox kwin_x11[5460]: kwin_scene_opengl: Invalid framebuffer status:  "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT"
Mär 02 12:58:05 darkbox kwin_x11[5460]: kwin_effect_blur: Failed to create an offscreen framebuffer

But I will get an HDMI cable and see if there is a difference.

…and the plasma panel switch always to upper side of the screen.

ok. and… i borrow me an HDMI cable (best quality v2.0). Unfortunately, I can no longer manage the resolution of 5120x1440. So this is probably not a solution. Damn.

Create a bug report at bugs.kde.org

My monitor sometimes change resolution to 640x480 when wake up from sleep. Its been happening on linux since I remember, both on gnome on kde. I never checked log before, I will report back if I found something. I am on HDMI (Intel) though not Display Port.

Same as Mika. The problem started precisely when I upgraded from KDE5 to KDE6. I’m on HDMI.

I use my monitor’s input selection to toggle between my employer-provided laptop on VPN and my personal workstation. If my workstation running KDE6 goes to sleep, when I return it is reset to an unusable resolution, either at login screen still at the dekstop.

https://bugs.kde.org/show_bug.cgi?id=482974

Happened the same problem today! Logs show

kernel: i915 0000:00:02.0: [drm] ERROR LSPCON mode change timed out
kernel: i915 0000:00:02.0: [drm] ERROR LSPCON mode change timed out
kernel: i915 0000:00:02.0: [drm] ERROR LSPCON resume failed
kernel: i915 0000:00:02.0: [drm] ERROR LSPCON mode hasn’t settled

I think my issue is related to this