➜  ~ cvt 1680 1050 60+
# 1680x1050 59.95 Hz (CVT 1.76MA) hsync: 65.29 kHz; pclk: 146.25 MHz
Modeline "1680x1050_60.00"  146.25  1680 1784 1960 2240  1050 1053 1059 1089 -hsync +vsync
➜  ~ xrandr --newmode "1680x1050_60.00"  146.25  1680 1784 1960 2240  1050 1053 1059 1089 -hsync +vsync
➜  ~ xrandr --addmode None-1 "1680x1050_60.00"
➜  ~ xrandr --output None-1 --mode "1680x1050_60.00"
xrandr: Configure crtc 0 failed
➜  ~ xrandr --output None-1 --mode 1680x1050_60.00
xrandr: Configure crtc 0 failed