Dual screen with Awesome WM

xrandr –output HDMI-1 –off
xrandr –newmode “1680x1050_gtf” 147.02 1680 1784 1968 2256 1050 1051 1054 1087 -HSync +Vsync
xrandr –addmode VGA “1680x1050_gtf”
xrandr –output VGA –mode “1680x1050_gtf” –left-of LVDS

1. My first attempt turned out the error “xrandr: cannot find crtc for output VGA”, the reason was I did not turn HDMI-1 off. I dunno how HDMI-1 exists on my laptop, but for sure i have to kick it off.
2. Awesome WM is awesome, and it default support dual screen.
3. My LCD is 22′ and 1680×1050