Configuring dual screens in Debian KDE can be tricky when the input monitors are of two different types. With Nvidia drivers, there is a solution with a couple of steps, when your monitor connection is not matched. For instance, a VGA and DVI as used in this example, can cause KDE to only recognize one monitor, typically the VGA. There is a two-step process to get through this.
Step one is to get the graphics driver to recognize the other monitor. To do this, click atl + f2 to get a search box and type kdesudo nvidia-settings. This will prompt for your sudo password and open a system GUI screen. Click the X Server Display Configuration. In the Layout box are the two screens. They might be stacked on top of each other, so use your mouse to grab a screen and drag it over next to the other.
Next, set both the x screen 0 configuration and resolution to auto. Set the position to left of. Click apply, and adjust as needed to get your screens looking right. Click on Save to X Configuration File. Note that this will save some but not all of your settings on reboot. To be sure it is going to act right every time, follow the next steps.
Open a commad prompt and log in as root. Open a terminal and from your home directory, type ls -al.
#ls -al
This will display all the hidden folders that start with a '.' followed by the folder name. You should see a folder called .kde. Next, cd into .kde/share/config. The ls command will show you a large amount of text files and other files that run to specify KDE settings.
# cd ./kde/share/config
Use the nano editor to open krandrrc.
# nano krandrrc
After the header comments, add in the monitors you wish to configure. For example, if you run xrandr on the command line and see you have a VGA-0 and a DVI-D-0, you would add the following:
xrandr –output DVI-D-0 –auto –left-of VGA-0
Type control and X to save, then test with a reboot.
