install xrandr
$ sudo apt-get install xrandr
check current modes
$ xrandr
Screen 0: minimum 8 x 8, current 1360 x 768, maximum 32767 x 32767
DVI1 unknown connection 1360x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1360x768 59.80*+
VGA1 connected primary 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1024x768 60.00*
800x600 60.32 56.25
848x480 60.00
640x480 59.94
find new mode to add
$ cvt 1360 768
# 1360x768 59.80 Hz (CVT) hsync: 47.72 kHz; pclk: 84.50 MHz
Modeline "1360x768_59.80" 84.50 1360 1432 1568 1776 768 771 781 798 -hsync +vsync
add new mode
$ xrandr --newmode "1360x768_59.80" 84.50 1360 1432 1568 1776 768 771 781 798 -hsync +vsync
check new mode
$ xrandr
Screen 0: minimum 8 x 8, current 1360 x 768, maximum 32767 x 32767
DVI1 unknown connection 1360x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1360x768 59.80*+
VGA1 connected primary 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1024x768 60.00*
800x600 60.32 56.25
848x480 60.00
640x480 59.94
1360x768_59.80 59.62
set new mode
$ xrandr --output VGA1 --mode 1360x768_59.80 --auto
