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Separate X sessions on dual screens for KDE4

User avatar kazetsukai
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I've the OpenSuSE factory build of 4.6, and in the multimon category the only bugs I'm running into are (KDE4) applications like konsole not spawning on the right screen.

If on screen :0.1 I run/click konsole, then on screen :0.0 I do the same, the next konsole window spawns on :0.1 instead of :0.0. Until I

Code: Select all
killall konsole &


All konsole windows appear on screen :0.1, regardless of what screen I initiated it from. I believe Dolphin behaves the same, as do other KDE4 applications.

For now, it looks like they have Plasma in the right place. I wouldn't know about KWin, as I use Compiz (and will continue to do so until the KDE4 compositing configuration matches the featureset of Compiz in usability and customization).

As I lost 4 monitors in an unfortunate multimon mount accident I've had to buy new ones, and they're all uniform (same res, pixel pitch, size) so I don't know how well or poorly Plasma handles dead space. I have 3 now with two X screens but will have 6 by the end of the month with 4 X screens, so I will test and see how Plasma and friends handle just about any configuration I can think of.

All in all, great improvement. Thank you KDE team!
User avatar bcooksley
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This will be because Konsole, Dolphin, System Settings and other similar applications are unique applications, meaning that only one instance of them can be running at any time.

Thus, the first instance will absorb the DISPLAY variable of the screen it is started on, and all future new windows will appear on that display. This is because when you run a unique application again, it simply sends a message to the first instance of the unique application, which usually then opens a new window.


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User avatar kazetsukai
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bcooksley wrote:This will be because Konsole, Dolphin, System Settings and other similar applications are unique applications, meaning that only one instance of them can be running at any time.
In KDE3, Konsole & Friends™ all spawned new processes, which allowed for them to be spawned on multiple screens at once. KDE4's konsole only ever lists one process, be it with one or twenty windows. This saves memory and is considerably better performing.

However, from the user's standpoint, this is a bug. The user shouldn't have to manage an application to one display when the icon for that application is available on all screens... especially the default file manager and terminal application. Notably, Google Chrome and Firefox also have this limitation, but you can use profiles in Firefox to get around this (And I think the separate process architecture in FF4 may resolve this issue).

I would imagine the fix being another konsole/dolphin/etc process spawned per screen. This isn't a blocker like Plasma/KWin was, but it is definitely an in-your-face annoyance. For the time being it is probably best to use another terminal application or file manager if one needs them on multiple screens at once.

I'm running into other bugs as well, but these are less critical:
  • The 'Run Command' prompt always spawns on Screen :0.0, regardless if it was initiated from the :0.1+ Plasma workspace or from Alt-F2 when an application on screen :0.1+ has focus. (Real annoyance...)
  • Localization of the Plasma panel, in addition to widgets, the desktop and context menus is only applied on Screen :0.0's instance. Does this need to be re-set for every instance?

Overall, I'm really impressed by the progress. Once I have a solid list of bugs, I'll start filing them against the tracker.
EyeOfCat
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different plasma have same resolution.
I have 2 mons 1280x1024 and 1024x768. plasma on small one (:0.1) have 1280x1024.
there can be some workaround with compiz, but it isn't all

-window doesn't recieve back keyboard(and sometimes mouse) focus when i switched to app on another screen and then returned to it. I have to change window state(roll it up or turn it to taskbar) to make it get back input focus.
-can't set up all the settings on plasma :0.1, they are in inactive state.
-localizateion problem as well.
-lancelot appears only on :0.0

will be tools in kde settings to configure two displays when they are separate x screen, like xfce4(this de offer complete support to separate X screen) has?
might0254
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I just tried the dual screen configuration the it works perfectly. Thank you so much for posting this useful information :)
koosjr
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I am using KDE for the past 9 years. I started using dual monitors on Mandriva 2008 Spring with KDE 3.5.9 and it worked perfectly although I had to manually write the xorg.conf file.

I use two different screens on different resolutions and both are running a separate X-session. One screen is driven from the onboard Intel card and the other from a Nvidia card.

However, my OS is pretty old by now and I really do need to upgrade to take benefit of the new browsers and software - although the old versions serves me well.

I tried Mandriva 2010.2 as well as Kubuntu 11.04 but on neither of them I could make a dual monitor setup run in any way. Only a single monitor runs at a time. With the xorg.conf file that worked on my KDE 3.5.9, it does not even start KDE.

Dual monitor setups are common today since it helps a lot to improve productivity. If one is used to multiple monitors, there is simply no way going back to a single monitor.

I searched all over the net to try and find help on how to get dual monitors to work on KDE 4.X but without much success. None of the tools like RandR can config the system and since I am not a programmer but just a normal user, it is obviously not an issue I managed to solve.

What exactly is the issue here? Dual monitors worked perfectly on KDE 3.5.9 and although a loyal Linux user, I simply cannot understand how it so often happens that things that worked perfectly in an versions, simply does not work in newer versions. I really do need two monitors, it makes a huge difference for day to day tasks.

The only other option, is to go to Ubuntu with Gnome because it works there, but I could never get to like Gnome.

Any advise or update of status for KDE would be appreciated.
User avatar kazetsukai
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While the KDE team has provided the bare minimums to get multi screen working, its still buggy/hacky and we're just not seeing application-level support. This is true across the board (not just with KDE).

I have a dreadful feeling in my gut that this issue is the victim of X11, and the lack of support for compositing + merged/mixed framebuffers (Xinerama). I don't honestly think it is reasonable for every application developer to add support for multiple screens/multiple processes when other platforms just don't have this issue.

For those that have a business requirement to have -separate (X11)screens-, I don't think there can reasonably also bee a requirement for single session. If you need multi screen, you're likely better off with multiseat.

For those with a need for more than two (physical)screens with one session (not necessarily more than one X DISPLAY), there are a couple (albeit expensive or hacky) workarounds.

1) A solution like Matrox TH2G - you can drive 3 screens on one DVI port at 1920x1080_50 each, as long as it is uniform (all screens the same resolution). Combined with TwinView you can accommodate up to 6 (physical)screens with full functionality. I have a 6 screen setup and this is really THE only way to get everything working 100%. Cost? $300 per DVI port.

2) Use Xinerama(deprecated...), and XGL (deprecated!!!) on top of it. I used to do this, it works if you have packages. NVIDIA, amongst others have objected to this approach and overall people agreed: You're abstracting hardware features from the applications this way. On the other side, almost everything works, until it starts breaking from decrepit and unmaintained code.

I really hope solutions like Wayland address this, its a glaring limitation.
Tilo
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My apologies if this is in the wrong section.. I have a question that I felt would be best answered on this forum.. My brother and I are trying to play a emulator on monitor 2, while I stream the internet/play games on monitor 1. Unfortunately, this is not possible. As soon as his emulation is set up and try to go to monitor 1 to look up something, he becomes unable to play his game.
I have a Dell XPS 8300
with 3.40ghz
8 gigs of ram
Windows 7 64 bit

Any help would be wonderful and greatly appreciated :)

P.S. We have the copies of the games, they are just to scratched to read.
User avatar kazetsukai
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It looks like Dolphin added multi DISPLAY support in a recent version. I've switched from SuSE to Arch so things are a little newer.
non7top
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Yup, yakuake,konsole,rekonq and many others are still broken. I'm not even able to use hotkeys on my second screen. Makes me very sad since separate screen is a killer feature when comparing win7 to kde4.
houzi
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I made my xorg.conf file in Gnome and copied it without any changes to my new Slackware/KDE partition.
It uses xinerama and is not perfect since I don't think that my GPU is handling the rendering very well. It does however provide me with a dual screen desktop with the right monitor being in portrait mode.

My xorg.conf.

Hope this will help while we're waiting for Wayland or better xorg support.
sashcroft
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Hey houzi,

Thanks for the share, i still can't find any fix to the problem, so i suppose i'll try your config file til i find a better way, thanks :)

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Baileykos
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f it is so easy to implement that a normal user can do it, it should be peace of cake for someone who already know the code and already have the developing tools set up. And there are always more important issues like families, friends and a real job. If those thing was not more important I would be busy reading op on all the things needed for fixing bugs in kde :)
Thanks , :(
Lachu
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I didn't read whole topic, but I have an idea.

Login manager should allow to drop input/output device. When user login, login manager will search for dropped devices and pair each free device into new session. New session will only starts with not dropped devices used by login manager.


Lachu, proud to be a member of KDE forums since 2008-Nov.
User avatar Nate_KS
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I have been away from KDE for some time. For a couple of months I have been running Slackware Current along with the latest Plasma5 packages from the alienbob repository on my Thinkpad T410 laptop. My experience has been very positive with no crashes and a very smooth and responsive desktop. I would also like to move to the same setup on my desktop machine, a ThinkCentre M73 with onboard Intel graphics with dual monitor outputs.

For several years I have run Debian and now Devuan on this machine with a custom xorg.conf that enables ZaphodHeads mode and using Xfce for my desktop. It has worked well over the years with having independent desktops on each monitor so that I have four workspaces on each desktop. The beauty of this setup is that changing a workspace on Screen 0 does not change the current workspace on Screen 1 and vice versa. At present I change focus between the screens merely by moving my mouse to which ever screen I want to use.

I would like to have this capability when using Plasma5 but so far have only been able to achieve an extended desktop where both monitors share a given workspace. This makes it impossible to have Emacs open on Screen 1 and then on Screen 0 switch between the workspaces that I use for browsing or reading mail without also losing access to Emacs on Screen 1.

What am I overlooking?


Happy Slacker and Plasma 5 user!

 
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