My installation of Kubuntu 12.04 does not switch to the default external monitor when I plug in nor does it switch back to the laptop monitor (Intel HD 3000) when the external one is plugged out. Both are recognized in the System Settings -> Display and Monitors -> Size and Orientation. I can set the settings manually, but I want it to happen automatically. The hardware key doesn't work if the machine woke up without the external monitor. Any ideas?
I have the exact same problem and would like to know if theres a workaround for this. Its one of the reasons preventing me from switching unfortunately. I have been told that it is possible using xrandr but i am not sure how...
Edit: Im actually appalled at how hard it is to get Kubuntu (or any other linux distro as far as i can tell) to just "work" as you would expect it to.
The best option i have found till now is to run the xrandr command using the --auto option at startup. This will automatically enable all available displays to their preferred resolution/rate etc
In Kubuntu, this can be run at startup in ~.kde/share/config/krandrrc
[Display] ApplyOnStartup=true StartupCommands=xrandr --auto
There are still a few problems however.
If for example you want to enable only your external monitor if it is available and enable your laptop display if it is not available, this appears to be quite hard to do without writing some bash script to parse the output of the xrandr command.
Another problem which i really find annoying is that xrandr (or kubuntu/linux) does not adjust itself well when you remove a display on the fly. If i have my external monitor plugged into my laptop and decide to remove it while kubuntu is running, all i seem to get is error messages and i cannot seem to find a way to automatically make it switch to the laptop display (as you would naturally expect it to).
I really really hope theres a better alternative to this setup. It must put a lot of users off to create such a complicated an elaborate setup just to get external monitors working.
I might post this reply as a new question in the hopes that someone would be able to point out better options.
EDIT2: I also noticed that gnome session automatically performs this switching so its deffinatly functionality that is available.
Why does Kubuntu not have such a standard feature?
EDIT3: Kubuntu 13.04 actually has this automatic switching feautre. It has been implemented as part of kde 4.10. The only problem is that i find Kubuntu 13.04 really really buggy compared to 12.04
EDIT4: Kubuntu 13.10 has been released and I can honestly say that it is a very stable version which you should change to. It contains the support for switching automatically between different display configurations as you plug in and out monitors. Highly recommended!