1. Use the latest Nvidia graphic driver from X updates PPA (260.19.29/270.18 is tested).
2. Modify /etc/X11/xorg.conf to add the two lines to the "Device" section:
Option "ConnectedMonitor" "DFP-0"Option "CustomEDID" "DFP-0: /proc/acpi/video/IGPU/LCD0/EDID"
With these two steps, LCD should work well. Additional external monitors can be added. Also, support of brightness control can be added. Following are my xorg.conf: