Graphics Administration Guide (July 2008)

The actual amount of power saved and the recovery time for each of the states is monitor
dependent and may vary widely. The customer can compensate for this by choosing
an appropriate level for the monitor that is currently in use.
By default, the DPMS level used is 0 or On (i.e. no power savings). If you wish to use
power saving, set the following XF86Config file entries before starting the server:
standby time, suspend time, and off time. Also set the Option “DPMS” “on” in the
monitor section.
DPMS should not be confused with screen blanking or screen saving. Screen blanking
will merely cause the screen to go dark. Screen saving will display a changing pattern
on the screen to avoid the burn-in of a static image. Neither of these will cause any
power saving to occur.
The DPMS Extension lets individual users customize their personal DPMS settings to
meet their work styles and any restrictions imposed by their employers. For example,
an employer may decide that all monitors must save power after 30 minutes of idle
time. The individual user may decide that 30 minutes is too long, and adjust the time
downward to meet their work preference.
More information (including sample code) on the DPMS Extension entry points can
be found online, via the man pages. The extension entry points are:
DPMS
DPMSQueryExtension
DPMSGetVersion
DPMSCapable
DPMSSetTimeouts
DPMSGetTimeouts
DPMSEnable
DPMSDisable
DPMSForceLevel
DPMSInfo
XFree86 provides four options that may be set in the ServerLayout section that may be
used to support this functionality. The options are: blank time, standby time, suspend
time, and off time. The following example sets these to 10, 20, 30, and 60 minutes
respectively.
Section “ServerLayout”
. . .
Option “blank time” “10”
Option “standby time” “20”
Option “suspend time” “30”
Option “off time” “60”
. . .
EndSection
display power management signaling (DPMS) 27