View source for DPMS

== Display Power Management Signaling ==
A VESA interface standard that defines four power management modes for monitors in idle state: 
#on
#stand-by
#suspend
#off. 
Using DPMS, the display controller (typically the video card or chip from which the monitor receives signals) sends a signal along two signal lines to the monitor, instructing it to enter into one of the four power management states.  Those two lines are the horizontal sync (h-sync) and vertical sync (v-sync) lines.

=== Linux X11 ===
As of Xorg 1.8 DPMS is auto detected and enabled if ACPI is also enabled at kernel runtime. 

See [https://wiki.archlinux.org/index.php/Display_Power_Management_SignalingDisplay Power Management Signaling]