[SOLVED] Mageia 4 KDE docking station display selection ?

[merlin]

I have a Dell Latitude E66430 laptop and a Dell docking station with HDMI connected monitor. I am using KDE.

Ideally, I want to use the LCD laptop screen when undocked and to use the HDMI monitor when docked.

The LCD laptop screen uses a Intel chipset and the HDMI output uses a nVidia chipset.

xorg.conf seems to setup both graphics drivers (using noveau for nVidia) but puts the HMDI monitor logically to right of the laptop's LCD screen. But I only want 1 screen at a time.

I modified xorg.conf to use just the HDMI output and this works until I dock the laptop then the HDMI monitor goes blank with only a mouse (mouse can disappear off the left edge of the screen). Undocking, allows the HDMI to show my KDE desktop.

Does anyone know how to modify the KDE behaviour of the docking mechanism so that I can use the HDMI output to show my KDE desktop whilst docked ?

[merlin]

Solved it. There is a KDE program called kscreen which shows the current monitors.

However, kscreen is context sensitive. This means, what kscreen shows in docked and undocked situations can be different. Therefore, in undocked mode, I only saw HDMI-1 as expected. But then I tried whilst docked and discovered DP-2 was to the left of HDMI-1 but my laptop screen was not active because of my xorg.conf setting. I used kscreen whilst docked to untick the DP-2 monitor and that allowed HDMI-1 to be used on it's own.

[merlin]

kscreen messes up when the laptop is left alone. I turned off the screensaver but something seems to be sensing when the user input is idle.

The mess up causes my external monitor to show no output. If the laptop is then undocked then the HDMI comes alive again but docking again shows no output again.

I determined that the kscreen settings are stored here:
~/.kde4/share/apps/kscreen/

I deleted the directory containing the kscreen files
rm -rf ~/.kde4/share/apps/kscreen

I docked the laptop again and kscreen does not show the KDE panel anymore but I can right click on the desktop to access "run command". I enter "kscreen" to run the kscreen GUI and unclick DP-2 with only HDMI-1 selected. Clicked OK, and the KDE panel comes back onto my external monitor screen. This is working again.

I have found out to stop kscreen from being used by doing:
disable KScreen KDED module (KDE4 System Settings -> Startup and Shutdown -> Service Manager, uncheck "KScreen 2")

Lets hope my external monitor display is now stable.