Hello everybody.

First of all, I don't know if this problem is related to Plasma or Kwin, I'm guessing Plasma because of the way to workaround this that I outline further below. Feel free to move to the appropriate forum.

The problem goes like so:

I have a Thinkpad T400 with Intel GPU, and my desktop with an Nvidia 9600GT. Both are running KDE-4.6 (.0 on my Desktop, .2 on my laptop) and both show the same problem, so I don't think this is related to xrandr/Twinview (what I use in each to manage multiple screens).

At work, with the laptop, I sometimes connect an external 19" VGA monitor. At home I sometimes connect a 22" VGA monitor, besides my normal 23" main monitor. Everything works fine when switching from single screen to dual screen. I seem to have lost the ability to have separate activities on each screens as I had managed on 4.4, but that does not make me sleep less. I can add and configure panels on separate screens and everything works fine.

The problem comes when I switch back to single screen (for example, when I first turn on the laptop at work/when I am not using the external monitor, or when at home I have to give back the 22" to my parents ). At that point, something gets broken with Plasma. The symptoms I am experiencing on both my laptop and my desktop, is that windows do not show up. I mean, they are on the taskbar, I can invoke the window menu and move them around, I even see the geometry/position being displayed on where the window should be, but when I hit enter, so as to finish moving the windows, the window does not appear where it should be. It's not that it's there but invisible, since cursor does not change if I was moving a terminal, and right click always brings up Plasma's desktop menu.

The only way I have been able to workaround this was by having two different sets of plasma configuration files, one for single screen and one for dual screen, and switching between the two sets, especially when I'm about to switch back to single screen. Mind you that if I switch back to single screen, at least on my laptop I don't see an issue like the one I described, but I see it next time I relogin to KDE.

At first I thought this was a Twinview problem, related to it's closed nature, but I saw this happen again to me yesterday on my laptop, when I brought it home and turned it on.

Sorry for the length of the post, but it was the only way I could describe the issue. If anyone needs any more information, please let me know and I will be happy to provide.

Thanks in advance
GODLiKE.-

I have the same problem with my EeePC 1201n (Nvidia Ion graphics). It got to the point where I stopped using KDE altogether on it. One workaround is to create a second activity for the default screen. When you switch back to a single screen and windows won't appear, switch to the other activity and then back to the default one. Everything will magically be back to normal. It's ugly and shouldn't be that way, but it is.

I'm using KDE on another laptop right now with an Intel graphics chipset, and I haven't experienced the problem. I'm not sure if this is an Nvidia vs. KDE issue, but I wouldn't be surprised if it were.

NVIDIA (the binary blob) doesn't support XRandR at all, which may be the cause of such issues.

No, in this case, I was using Twinview, which is part of Nvidia's blob.

As it was stated above, this problem appears both with XRandR and Twinview. I have not tried the activities fix (though I did notice that on 4.4, if I had two activities, KDE automatically arranged one activity per screen when in dual-head mode. This does not seem to happen on 4.6, at least on my NVIDIA box I have two activities and they do not get assigned like so).

Is this problem known? Should we file a bug report?

This problem is clearly not nVidia related. I am using KDE 4.6 on openSuSE (all patches applied), and my Dell Studio laptop has an ATI graphics chip. I see exactly the same problem. I did not see it on 4.4.

I recently disconnected the second monitor on Toshiba Satellite laptop with an Intel graphics chipset and experienced the same problem. So, you are right, it is not limited to proprietary drivers.

This is KDE Bug #259183.
Mentioned there is that the problem resides with the file
plasma-desktop-appletsrc
and a kludge is to have two versions of that file, one for dual-screen and one for single screen.

Yes, my workaround (of course it's not a solution) is to have two sets of plasma-desktop*rc files (actually three, one for single, one for dual monitor on the right and one for dual monitor on the left). Also a script to switch between sets and reload plasma.

But of course this is no solution I upvoted the bug, I hope it gets the needed attention. If anybody else is experiencing this, please uptove it too.

Cheers
GODLiKE.-

This is my one HUGE issue with KDE. fwiw I'm working on a HP G71 laptop. At work I use a second monitor and KDE is excellent. (recently switched from Unity) But when I am on the road or working from home on single monitor I have same issue, I can NOT view or "see" the active screen except when I hit ctrl-alt-tab, so I switch to LXDE as a work around,until I get back to second monitor. I'm not skilled enough yet to know how to setup alternate desktop files as others have mentioned yet. If anyone would be kind enough to post directions on how to do this or point me in the right direction I'd be grateful. Also would like to know how to "up vote" the bug. fwiw, over all I LOVE KDE. Been using it for just over a month.

Based on one or more aliases someone else created that I found somewhere on the web, here is my work-around:

Code: Select all

alias savesingle='cp ~/.kde4/share/config/plasma-desktop-appletsrc{,-singlehead}'
alias restoresingle='cp ~/.kde4/share/config/plasma-desktop-appletsrc{-singlehead,}'
alias savedual='cp ~/.kde4/share/config/plasma-desktop-appletsrc{,-dualhead}'
alias restoredual='cp ~/.kde4/share/config/plasma-desktop-appletsrc{-dualhead,}'


Before I connect a second monitor, I enter:
restoredual
Similarly, before I disconnect and know that I will be on only the laptop screen, I enter:
restoresingle

I use the save* aliases when I have made some kind of configuration change (and, you have to use them at least once to get the restore* aliases to work).

I have a lenovo t400 with a dual monitor through a docking station, and was experiencing the same issues when trying to switch between monitors.

I tried ingham's suggestion and it does the trick for me.

I combined the aliases with xrandr:

Code: Select all

alias switchsingle='restoresingle && xrandr --output DVI-0 --off && xrandr --output LVDS --mode 1440x900 --rate 60.1'
alias switchdual='restoredual && xrandr --output LVDS --off && xrandr --output DVI-0 --mode 1680x1050 --rate 59.9'

and this allows me to use 'switchsingle' and 'switchdual' to switch between monitors on the command line.

Thanks!

I also ran into this problem yesterday. I believe it began for me once I moved my panel (on the single screen configuration) to the bottom. With both at the top it seems to work okay. I added my votes to the bug.

As panels on the top seem to be working okay for me I haven't tried this, but thought it might be useful. If you go to "System Settings" -> "Startup and Shutdown" there is an option to run a script "Pre-KDE Startup" (or you could just put a script in ~/.kde/env manually). I created a simple script to run xrandr, grep for the connected monitors, and output it to a file. It seemed to work just fine. Perhaps this could be used to detect what is connected and automatically move the correct plasma-desktop-appletsrc file into place.