# First create a modeline
~$ cvt [width] [height] [hertz]
# e.g: cvt 1920 1080 120
# You will get a modeline in the output of this command Copy it!
# Note: Dont close the terminal after done theres an extra step in the end!
# Next create a new resolution mode
~$ sudo xrandr --newmode [modeline from cvt output]
# Now you need your moniters/displays "Display name".
# To get this..
~$ xrandr
# You should see something like "HDMI1" , "VGA-1" or "Virtual1" (If using a virtual machine).
# copy this this is the display name
# Now add the new resolution to your display monitor.
# The modline name is the name in " " in the modline.
~$ sudo xrandr --addmode [display name] [modeline name]
# After this open display settings.
# Your new resolution should be visible now! :)
# To make the changes stay on your next restart copy the secont and third command to ~/.profile.
# This file executes on each login so the commands will automatically run.
# Here's how you do this:
#open a new terminal
~$ sudo nano ~/.profile
# dont change anything just go to the bottom of the file and paste the commands. :)