1. Find the monitor or display using the xrandr command

$xrandr

Here, DP-1 will be your Display / Monitor ID

2. Get the Modeline string using one of below command

cvt 1366 768

or

gtf 1920 1080 60

3. Add new mode using Modeline output

xrandr --newmode "1920x1080_60.00"  172.80  1920 2040 2248 2576  1080 1081 1084 1118  -HSync +Vsync

4. Add created new mode to desired display

xrandr --addmode DP-1 "1920x1080_60.00"

Once this is done you can see the Resolution in the Settings > Display > Resolution dropdown.

5. Add to your bash profile to make it permanent

sudo gedit ~/.profile

Add below two commands to there.

xrandr --newmode "1920x1080_60.00"  172.80  1920 2040 2248 2576  1080 1081 1084 1118  -HSync +Vsync 
xrandr --addmode DP-1 "1920x1080_60.00"

Note : Check the maximum resolution that monitor supports also otherwise it will display something like this.

References :

• https://blog.mohessaid.com/fix-external-monitor-resolution-in-ubuntu-20-04-9c24cee65950
• https://unix.stackexchange.com/questions/227876/how-to-set-custom-resolution-using-xrandr-when-the-resolution-is-not-available-i
• https://askubuntu.com/questions/138408/how-to-add-display-resolution-for-an-lcd-in-ubuntu-12-04-xrandr-problem

#display, #ubuntu