SUMMARY I'm running the latest release on Manjaro with dual screens set up. The issue I'm having is that when the displays go to standby, then wake back up, Plasma doesn't seem to remember my config. My DVI display wakes up first, Plasma detects it, snaps into single display config, then the HDMI display wakes up, Plasma detects it, and then snaps back into my configured display layout. Plasma should just remember the layout, in fact, as the computer is still running and the displays haven't actually been disconnected, there's really no need for Plasma to re-detect displays at all. STEPS TO REPRODUCE 1. run multiple displays (one waking up quicker than the other may be important, I'm not sure) 2. displays should go into standby 3. displays wake up OBSERVED RESULT Plasma re-detects attached displays twice. EXPECTED RESULT Plasma should not need to re-detect displays at all, computer should be just as I left it. SOFTWARE/OS VERSIONS Linux/KDE Plasma: 4.19.6-1-MANJARO (available in About System) KDE Plasma Version: 5.14.4 KDE Frameworks Version: 5.52.0 Qt Version: 5.11.2 ADDITIONAL INFORMATION DVI screen is an aluminum Apple Cinema Display. HDMI screen is a Dell 27" Both screens are connected to the same AMD video card running amdgpu driver.
This is using X, not Wayland.
I recently tried once again to transition to Wayland and I see this same behavior. After standby my two monitors come back up reversed left/right. Monitors do not switch after log out/login or reboot. Given my cabling it is inconvenient to reverse them physically so I am staying with X11 for now. I noticed that when in Wayland there is no 'primary monitor' selector at 'SystemSettings->DisplayAndMonitor' System: Asus Z170Pro/Radeon RX570/Fedora33,
This bug is still with us in 5.24.5, at least with wayland. I have two side-by-side monitors, with the left one rotated and the right one primary. When I return from standby, the left screen reduces the resolution, isolating both screens. I cannot move mouse between them anymore as their borders do not touch anymore. It also happens if I simply power it off and on again. From kscreen, I can see it detected much less resolution options, with the greater one being 1024x768 (much less than the supported 1920x1080). If I turn it off/on again, it correctly detects the resolution. However, as the last time it reduced the resolution, it will stick with that lower resolution until I manually fix it. The desktop background/plasmoids are also inconsistent. I normally use notes but it is rare to ever return to the same "desktop". Each boot, it looks like it create a new desktop config and forget everything I did with it. And, sometimes, the background just becomes a plain black.
I have a setup very similar to what Luiz Angelo De Luca described before me. And Plasma becomes unusable after my displays are woken up, as my main (horizontal, unrotated) display also shows content in a rotated way. Usually a reboot resolves it, apart from the background resetting to the default Fedora one on the main (unrotated) display. I don't dare touch any settings in this situation, fearing that my proper config gets accidentally overwritten by a problematic one. My system: Operating System: Fedora Linux 36 KDE Plasma Version: 5.24.5 KDE Frameworks Version: 5.93.0 Qt Version: 5.15.3 Kernel Version: 5.17.11-300.fc36.x86_64 (64-bit) Graphics Platform: Wayland Processors: 32 × AMD Ryzen 9 5950X 16-Core Processor Memory: 31,3 GiB of RAM Graphics Processor: AMD Radeon RX 6600 XT
I can confirm this bug. I have a setup with two identical monitors, same resolution and orientation, connected with HDMI. If I do not turn on the monitors on first before waking from suspend, the setup will be messed up. It might turn into single monitor, positions may be swapped, wallpapers may be swapped. This is reproducible. Sometimes just turning the monitors on and off is enough to mess up the configuration. Operating System: Kubuntu 22.04 KDE Plasma Version: 5.25.5 KDE Frameworks Version: 5.98.0 Qt Version: 5.15.3 Kernel Version: 5.15.0-50-generic (64-bit) Graphics Platform: X11 Processors: 6 × AMD Ryzen 5 3500X 6-Core Processor Memory: 31,3 GiB of RAM Graphics Processor: AMD Radeon RX 580 Series Monitors: Philips PHL243VB x 2 @ 1920/1080
Unfortunately everything people have been reporting here since the original report by Ben is unrelated and those are separate issues. For those people, if you're still experiencing those issues in Plasma 5.25 or 5.26, can you ask you to file new bug reports? Thanks. As for the original issue: > My DVI display wakes up first, Plasma detects it, snaps into single display config, then the HDMI display wakes up, > Plasma detects it, and then snaps back into my configured display layout. Plasma should just remember the layout, > in fact, as the computer is still running and the displays haven't actually been disconnected, there's really no need >for Plasma to re-detect displays at all. Unfortunately this is the way it has to be, because to the system, "disconnected" and "hasn't woken up yet" look identical, so the system has no way of knowing that there's a slow display that'a about to wake up, vs a disconnected display. If the system remembered the previous dual-display state, but the HDMI screen actually had gotten disconnected, then you could move your cursor off into where it used to be, and windows would still be there too, but all of those things would be invisible. So it has to remain the way it is, I'm afraid.