I'm a new Linux user trying to change the screen resolution as there is no option under display. I have successfully managed to add new resolutions by fluke by following online guide. I don't have a GPU, I don't know if this is the issue? Below is my xrandr -q output.root@kali:~# xrandr -qxrandr: Failed to get size of gamma for output defaultScreen 0: minimum 1280 x 1024, current 1280 x 1024, maximum 1280 x 1024default connected 1280x1024+0+0 0mm x 0mm   1280x1024       0.0*   1920x1200_60.00 (0x145)  193.2MHz        h: width  1920 start 2056 end 2256 total 2592 skew    0 clock   74.6KHz        v: height 1200 start 1203 end 1209 total 1245           clock   59.9Hz  1440x900_59.90 (0x156)  106.3MHz        h: width  1440 start 1520 end 1672 total 1904 skew    0 clock   55.8KHz        v: height  900 start  901 end  904 total  932           clock   59.9Hz
How to set custom resolution using xrandr when the resolution is not available in 'Display Settings'
command line;kali linux;xrandr;resolution
Here are the steps you need to add a new custom resolution and apply it. Following steps are for adding a 1920x1080 resolution, but you can use it for any other resolution you want. But make sure your monitor and onboard graphics support that resolution.# First we need to get the modeline string for xrandr# Luckily, the tool gtf will help you calculate it.# All you have to do is to pass the resolution & the-# refresh-rate as the command parameters:gtf 1920 1080 60# In this case, the horizontal resolution is 1920px the# vertical resolution is 1080px & refresh-rate is 60Hz.# IMPORTANT: BE SURE THE MONITOR SUPPORTS THE RESOLUTION# Typically, it outputs a line starting with Modeline# e.g. 1920x1080_60.00  172.80  1920 2040 2248 2576  1080 1081 1084 1118  -HSync +Vsync# Copy this entire string (except for the starting Modeline)# Now, use xrandr to make the system recognize a new# display mode. Pass the copied string as the parameter# to the --newmode option:xrandr --newmode 1920x1080_60.00  172.80  1920 2040 2248 2576  1080 1081 1084 1118  -HSync +Vsync# Well, the string within the quotes is the nick/alias# of the display mode - you can as well pass something# as MyAwesomeHDResolution. But, careful! :-|# Then all you have to do is to add the new mode to the# display you want to apply, like this:xrandr --addmode VGA1 1920x1080_60.00# VGA1 is the display name, it might differ for you.# Run xrandr without any parameters to be sure.# The last parameter is the mode-alias/name which# you've set in the previous command (--newmode)# It should add the new mode to the display & apply it.# Usually unlikely, but if it doesn't apply automatically# then force it with this command:xrandr --output VGA1 --mode 1920x1080_60.00Original source: https://gist.github.com/debloper/2793261I also wrote a script that does all these steps automatically. You can try it out if the above steps seem too complicated for you: https://gist.github.com/chirag64/7853413