SUMMARY I have two displays configured in Plasma - monitor connected by HDMI (primary) - projector (often turned off and connected by DVI) For first display I have 2 (virtual) desktops. In Pager I have set "slider effect". When I switch between them (clicking into Pager) I see desktop from second screen - sliding between my two virtual desktops. This is strange even that second display is turned off. STEPS TO REPRODUCE 1. Connect external display 2. Set "slider effect" for switching desktops 3. If is not set then set for Pager 2 (virtual) desktops 4. Switch between desktops - by clicking into Pager or using key shortcuts OBSERVED RESULT In sliding effect between first and second desktop is showing desktop from external display. EXPECTED RESULT In sliding effect between first and second desktop should not be shown desktop from external display. SOFTWARE VERSIONS (available in About System) KDE Plasma Version: 5.14.0 KDE Frameworks Version: 5.50.0 Qt Version: 5.11.2 ADDITIONAL INFORMATION
Additionally I can move mouse cursor on desktop related with projector. Even if it is turned off. SOFTWARE VERSIONS (available in About System) KDE Plasma Version: 5.14.3 KDE Frameworks Version: 5.51.0 Qt Version: 5.11.2
Are you using X11 or Wayland?
And please provide the output of: qdbus org.kde.KWin /KWin supportInformation
Created attachment 116356 [details] supportInformation
I use X11.
Created attachment 116357 [details] kscreen configuration
I don't see any bug here. You have two enabled displays. Of course the second display is considered. Turning the display off seems not to emit any hardware evemtd. You need to disable in kscreen.
Projector is usually turned off (actually in standby mode). Sometime I turns it on at evening or at night. Only I wonder why Plasma sees external display when it is turned off. Yes, I can disable it in kscreen, but then I will need to remember to do it every time when I turn off projector, and every time when I turn on I will need to configure this display. Even I can't switch on it, when is turned off I can move any window on this invisible desktop, and of course move mouse cursor itself.
Sorry, but nothing in Plasma is responsible for this behavior. Plasma is told by X11 which screens are there. X is told by the DRM subsystem. We are all just consumers of the missing hardware event. In the end better ask why your projector doesn't tell it's off.
@Martin Flöser You said: "Turning the display off seems not to emit any hardware evemtd. You need to disable in kscreen." So I did the test. I disabled second display (projector), restarted my PC and didn't see described effect. I turned on projector and it started searching (source of signal). Unfortunately Plasma shown nothing, any "Display Manager" to configure it - what I expected. Just didn't detect new display. Why? Of course in configuration (kscreen) I had set this display, only with option: "enabled": false, so I enabled it in System Settings. Now I have described effect, but also Plasma "sees" second display.
You had it disabled in kscreen. Kscreen saves the state. Sorry, but we cannot fix broken hardware - that is completely not in our stack. Report the issue to your gpu vendor or your projector vendor.
I don't think my hardware is broken. Plasma detects displays when config file for kscreen is missing. Both displays of course are turned on. Only I wonder if in described case (disabled second display) should appear "Configuration Display" applet? Or maybe this doesn't work because something is not handled in X11 or in driver (i915) :/.
> Or maybe this doesn't work because something is not handled in X11 or in driver (i915) :/. We only can present what the layers below report. The issue is either in the hardware, the driver or X Server. My guess would be hardware. That the intel driver fails in something like that is unlikely, but broken displays I have seen many (me looks at the Samsung screen in the office messing up mm and cm).