O mesmo problema aqui.
~$ lspci
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
Corrigido dessa maneira. Primeiro calcule vesa cvt:
~$ cvt 1280 720
# 1280x720 59.86 Hz (CVT 0.92M9) hsync: 44.77 kHz; pclk: 74.50 MHz
Modeline "1280x720_60.00" 74.50 1280 1344 1472 1664 720 723 728 748 -hsync +vsync
defina xrandr:
~$ xrandr --newmode 1280x720_60.00 74.50 1280 1344 1472 1664 720 723 728 748 -hsync +vsync
~$ xrandr --addmode VGA1 1280x720_60.00