cvt 1024 768 # 1024x768 59.92 Hz (CVT 0.79M3) hsync: 47.82 kHz; pclk: 63.50 MHz Modeline "1024x768_60.00" 63.50 1024 1072 1176 1328 768 771 775 798 -hsync +vsync xrander --newmode "1024-768_60.00" 1024 1072 1176 1328 768 771 775 798 -hsync + ysync xrandr --addmode default "1024X768_60.00"

In this example video width is 1024 and height is 768. Substitute these values with desired values.

The output would be...

Use the above results in this command xrandr --newmode [rate] [[width] [start] [stop] [total]] [[height] [start] [stop] [total]] [-|+hsync] [-|+ vsync] which will create the mode for the driver:

Last add the mode to the driver indicating the driver name and the mode name: