Hey all

Ever since trying, I have had problems with dual monitors in KDE. The output is displayed as soon as an external monitor is plugged and everything works fine, except I can only clone the output (or disable one of the screen and use the other one only), but I cannot have an extended desktop: I can set it up from Systemsettings, but when I press 'Apply' nothing happens.
I had such problem at least in SC 4.9 and 4.10, but I was hoping that it would be solved with kscreen (v. 1.0.1 as released in kubuntu 13.04) but the problem is elsewhere.
I recall having it to work at some point, I'm not sure what I did and when it did stop working.

I use an ATI card with fglrx 9.012 from ubuntu repos.
The dual screen works absolutely fine in gnome, so it's not a driver problem.

I don't even know where to put my hands or where to look for a log/report

thanks for all the help you'll want to give me

As you are using fglrx, have you tried using the ATI tools to configure your monitor setup?

ah! believe it or not, I hadn't thought of it, but it was that way I managed to have it working, months ago. and it still works, if I just reboot (or restart X) after configuring the settings.
odd enough, now I can even configure both "Clone" or side-by-side screens in KDE System settings, and they'll both work without restart.

So the problem is solved, thank you!
but I still wonder why it works that way, how long I can keep these Catalyst settings fixed and working (might be wrong but I don't recall changing them myself, so I'd suppose an update has reverted them?), and whether I/we can hope for an out-of-the-box working solution

In regards to a KDE provided solution, many distributions are now adopting KScreen from KDE 4.11 onwards, which will provide significantly enhanced support for a variety of setups. It will depend on the capabilities of your graphics driver to provide accurate information on your displays however, and to allow KScreen to make configuration changes (those using proprietary drivers may be potentially limited here).

I know, and Kubuntu is already providing Kscreen 1.0 in its 13.04 version (alongside KDE 4.10), and that is what I'm currently using.
Is it though a correct interpretation, that if it works with one (open-source) system like Gnome, there's no reason it shouldn't work with KDE?

While this is usually the case, the methods invoked by the GNOME tools may be different to those used by KScreen - which can expose bugs or other issues in the drivers. It appears that this may be the case here.