Hi.

I am running the latest and greatest KDE Neon. I've had this problem now for a few weeks. I try to work on it when I get a few minutes, but I cannot find an answer for this one.

I bought two new monitors. I removed the old monitors, and attached the new monitors to my system. Ever since then, almost every time my screen locker comes on, I come back to find that one of the screens is totally black, and the screen that should be on the right monitor is now on the left. The Right monitor has no wallpaper, no panel. I can still drag a window onto it, but the workspace itself seems dead. I cannot right click it, for example, to add a panel, change the wallpaper or any of the other context-sensitive options that should pop up. It is just dead, but usable space. I reversed my Displayport cables on my monitors to see if that helped, and made the appropriate adjustment in Plasma under the Display settings... but the problem persists

After some fumbling, I found the option to go into Edit mode (on the desktop that works), and click on "Manage Panels and Desktops"... which I've never noticed or played with before... I'm thinking it is relatively new. In that window, I see 4 displays: DP-2 (primary), DP-6, :0.0 (disabled) and :1.0 (disabled). :0.0 (disabled) has the new default KDE Neon wallpaper with the space ship landing, and :1:0 (disabled) is blank. The only screen of the four that looks right is DP-2 (primary) which has the wallpaper I explicitly set. DP-6 has the spaceship wallpaper (which I explicitly changed). I noticed that when I move these four items around, strange things happen with my screens/desktops. They do not correspond to what you think should happen.

My current hypothesis is that some part of the system still thinks it has the old monitors hooked up as well, and is maintaining two extra desktops. When the screen locks, then unlocks, it gets confused, and sets desktop 1:0 (disabled) to my right monitor, and slides DP-2 to my left monitor. What was on my left monitor before the screen locks, gets completely wiped from my configuration, and I have to reset everything for my displays. By corporate policy, screens have to lock every 5 minutes after inactivity -- so this is extremely problematic for me. It is possible my hypothesis is wrong -- i also applied some updates that day, and perhaps that introduced the problem... I'm not sure.

I would have thought that if I could delete the two unused Desktops from "Panels and Desktops Management", that would solve the problem... but there does not seem to be any way to remove them. When I click the 3 lines menu on any of them, the only option is to "swap with Desktop {whatever}". I cannot find any information on this subject.

Can someone please assist?



Thank you.

Addendum: Yikes... I just got back to my desk, unlocked my screen... now BOTH of my desktops are pure black, and not interactive... Since I cannot access "Mange Desktops and Panels" and I cannot get to "Configure Desktop and Wallpaper" when my desktops are dead, I did this:

Code: Select all

kquitapp5 plasmashell
kstart5 plasmashell

And the desktops came back to life... but they were still wrong... so something more must be going on here. I found I could not just run the second command, I had to actually quit plasmashell first... so it was not a plasmashell crash...

OK. I think I was on track with my working hypothesis above.

I just whacked all my kde and plasma settings and started over. The extra two displays disappeared, and it seems to be working normally now. That is a relief. Major pain there have to re-set up my desktops each time I leave and come back to my computer. I suppose if I knew more about the inner workings of KDE/plasma I would know which config files to address specifically, but I didn't have time to play with it. It has been a while since I refreshed my settings anyway... always good to do every year or two...

Well, I thought i had this. It worked for several days... now we are back to it... I don't show 4 monitors anymore under my "Panels and Desktop Management" window -- I see only two... but the same behavior is happening anyway... Whenever I'm gone for more than a few minutes, I come back, and one screen is pure black and unresponsive (even though I can move windows to it, I cannot right click it though). I need to redo my dektops, my panels and my desktop widgets...

doing this:

Code: Select all

kquitapp5 plasmashell
kstart5 plasmashell

Gets my wallpaper back and re-activates that monitor's desktop... but I have to do the rest by hand.

This has only gotten worse... the only real fix is to reboot. The problem is, that I'v always got at least a dozen windows open, and shutting down, restarting and getting everything open again is a lengthy process.

I have wiped my kde/plasma settings multiple times, swapped monitors around, changed the ports used on my graphics card... nothing seems to work. Every time I come back after my screensaver kicks in, it is like roulette. Most of the time, it messed up, and the only thing that seems to consistently put things back in order is a reboot of my system.

Hi, I only just joined, but I share your frustration. I have been fighting the same issue for a week, but I have finally solved it.

The problem is SDDM. When you drop to sleep, or even the lock screen, the system switches from plasma control of SDDM to SDDM auto control. If one monitor should be slower than the other to wake up and tell SDDM its awake, SDDM panics and thinks its gone, and tries to "save you" by moving the desktop to another monitor. And it messes it up as you and I have both seen. I have further issues as I use 4 screens, with two rotated. You think you got it bad?

So... the solution is to hard code the monitor arrangement and setting in SDDM using the built in XRandR tool. This should cause it to settle down. Basic instructions on how to do this are in the link below. Even though it talks about login, it applies inside plasma as well. You will want to add a "primary=" setting to the example used in the webpage, and you may need to set DPI and Scaling values. It is not as hard as it looks. Give it a shot and if you have questions give me a holler.

https://blog.victormendonca.com/2018/06 ... e-screens/

https://x.org/releases/X11R7.5/doc/man/ ... ndr.1.html

Hi Shad,

I did as you suggested, and I can definitively state that it did not work for me. However -- you did put me on the right track. The /usr/share/sddm/scripts/Xsetup file was the key for me. I didn't know about it. Since the problem seemed to be related to the unusually long "wake up" time that these monitors need, I simply put in "sleep 3" in the Xsetup file -- and that did it. It gives it a little more time for the monitor to wake up, so SDDM can address.

Thank you for putting me on the right track. It has been 24 hours, and it seems to be working. I think we got this one... but I'll give it another 24 before closing this out.

G

Ok, so this has still been a problem. My intervention above has decreased the incidence, but it definitely still happens. It drives me crazy... I have to reboot my machine every time and, most of the time, setup my widgets again from scratch.

It seems to me that the problem can be mitigated by logging in -slowly- when unlocking the screen. I'm a reasonably fast typist, especially for passwords that have been committed to muscle-memory... If I log in too quickly, the odds of the problem occurring seem to approach 100%. Once the problem manifests, the only realistic fix is to reboot, which always sucks because I'm perpetually logged into numerous systems, and have spreadsheets open, etc. It takes 5 minutes to close everything down, and 10 minutes to open everything back up again.

Ok... just bought new monitors... this is still happening. It has nothing to do with the monitors, their speed, their shape, the color of the bezel... This is is a KDE Neon thing... It is driving me absolutely nuts... Every time it happens, I lose 10 minutes. I can't afford that.

I installed the new monitors, and nuked all my KDE/Plasma settings, made sure that there are no extra displays on "Panels and Desktop Management" and it is still happening. I can't believe no one else is having this issue. I don't know to do at this point except bail on Neon altogether, which is a truly depressing proposition.

I filed a bug report on this. When I searched the bugs site, I didn't find anything... but people describe this issue in different ways. It turns out that this is, in fact, a bug in plasma. A nasty one that has bitten many users... I'm surprised no one said anything on these forums. The bad news is, there isn't a lot to do about it. No real work-around is provided. The good news is, it seems to be fixed in the next upgrade. We just have to be patient.

https://bugs.kde.org/show_bug.cgi?id=353975

grooveman wrote:I filed a bug report on this. When I searched the bugs site, I didn't find anything... but people describe this issue in different ways. It turns out that this is, in fact, a bug in plasma. A nasty one that has bitten many users... I'm surprised no one said anything on these forums. The bad news is, there isn't a lot to do about it. No real work-around is provided. The good news is, it seems to be fixed in the next upgrade. We just have to be patient.

https://bugs.kde.org/show_bug.cgi?id=353975

I think I'm experiencing this issue, if I plug in three monitors the system crashes. It's not the nvidia drivers I'm pretty sure. Hope this gets fixed soon it's pretty bad.

Thank the gods... I think they have finally fixed this... or at least close enough. It now only happens when my screen goes to sleep -- so I keep that from happening, and everything works. That was horrible... impossible to get anything done. I just hope it never returns...