DPMS - Display Power Management Signaling
Reduce Power Bill
DPMS is used to communicate between your monitor and computer to make your computer turn off your monitor when you have been neglecting it for a given period of time. DPMS is the interface to the Energy Star power saving functions for your monitor. Basically it lets your monitor suspend and power off automatically from inactivity.
In the Monitor section add:
Option "DPMS" "true"
Next, in the ServerLayout section add:
Option "StandbyTime" "10" Option "SuspendTime" "20" Option "OffTime" "30"
change your DPMS settings on the fly
xset dpms 300 600 900
DPMS in KDE
- You can find it under Peripherals -> Display. It is the third tab labeled Power Control
Special Notes: Nvidia users... Seems the latest drivers (The 6111 series atleast) don't support the standard DPMS setup. I had to add the following to my Device section as well:
(**) Option "dpms" "true" (**) NVIDIA(0): DPMS enabled
BlankTime is "fake" screen blanking: it makes the screen black but the backlight and power supply stay on. It doesn't actually do anything to reduce the power usage. Think of it as a really boring screen saver. The timeout defaults to 10 minutes.
In more recent Xorg versions, like the 7.2 that comes with Ubuntu's "Gutsy Gibbon", BlankTime is gone, and instead there is a Screen Saver section, which includes the options prefer blanking, allow exposures, timeout, and cycle. It works differently, too: prefer blanking actually switches the monitor to powersave mode (the alternative, if you turn it off, is an ugly X cross-hatch pattern) and there doesn't seem to be any way to get the old "fake blank" behavior back. I don't know what the difference is between timeout and cycle; the manual page doesn't say, nor does anyone else. Gutsy sets them both to 600 seconds.
In a CRT, this turns off the electron gun, but leaves everything else powered on so that the screen can recover quickly. The timeout defaults to 20 minutes.
This turns off the monitor power supply in addition to the electron gun. By default this timeout is set to 30 minutes.
This turns off all power to the monitor and is the most power conservative state. By default this happens after 40 minutes.
The default values are built into X, and need not appear anywhere else. That's why, if you grepped for timeouts, you may not have found them.
They can also be set via xset. You can set the blank timeout with:
xset s blank xset s 300
will tell X to use screen blanking after the system has been idle for 300 seconds (five minutes).
xset dpms 0 360 420
disables DPMS standby and sets the DPMS suspend time to 360 seconds and the off time to 420 seconds. In theory, this combined with the previous xset commands would first blank the screen at five minutes; then at six minutes, the display would go to suspend, turning off another minute later.
Timeouts can also be specified in the X configuration file: /etc/X11/xorg.conf. In the "Monitor" section, you need a line like:
Then, in the "ServerLayout" section (for Xorg 7.2 and later, make a separate ServerFlags section instead), include lines like this:
Option "BlankTime" "4" Option "StandbyTime" "0" Option "SuspendTime" "0" Option "OffTime" "5"
Caution: note the numbers are all small. xorg.conf needs times specified in minutes, not seconds as with xset.
Hint: when debugging timeouts, try setting them to unusual numbers like 765 or 666 instead of 300 or 600. That makes it easier to be sure whether you're seeing your own numbers or something coming from a system setting somewhere else.
Testing the monitor blanking modes. This will blank the screen (or activate the screensaver program, if you're using one) after a delay of one second. You need the delay because X gets a little confused about the order of events; it will blank the screen but immediate un-blank it, thinking the activity of your typing the command happened recently enough to come out of screensaver mode.
sleep 1; xset s activate
To turn the screen OFF after a delay of one second. You can also use standby, suspend, or on instead of off.
sleep 1; xset dpms force off
Sometimes it turns out that Xorg actually doesn't use DPMS when it's supposedly using DPMS, at least on a lot of systems. xset dpms force off merely makes the screen black; the backlight stays on.
Verify that the backlight does indeed turn off with: (vbetool's dpms options also include on, standby, suspend and reduced.)
vbetool dpms off
vbetool is part of the pm-utils package:
- Summary: Power management utilities and scripts for CentOS
- Description: The pm-utils package contains utilities and scripts for CentOS useful for power management.
DPMS (Display Power Management Signaling) is a standard to reduce power consumption in monitors. Typically, both the monitor and the video card must support the DPMS standard in order to receive any benefit from it. DPMS specifies four modes of operation (in order of increasing power savings): "Normal", "Standby", "Suspend" and "Off". Two signal lines, "Horizontal Sync" and "Vertical Sync" provide a method for signaling these four different states to a DPMS monitor.
A good technical resource on DPMS is available at http://webpages.charter.net/dperr/dpms.htm.
If you have a DPMS-compliant monitor, you might want to try enabling support for it under the Monitor section of your XF86Config file:
Section "Monitor" ... Option "DPMS" EndSection
To manipulate the DPMS functions, you can create/modify the following items in the ServerLayout section.
Section "ServerLayout" Option "BlankTime" "10" # Blank the screen in 10 minutes Option "StandbyTime" "20" # Turn off screen in 20 minutes Option "SuspendTime" "30" # Full hibernation in 30 minutes Option "OffTime" "40" # Turn off DPMS monitor EndSection
It's worth noting that BlankTime is not actually a power saving level at all. The screen is sent a "fake" blanking effect and defaults to activate after 10 minutes. Alternately, it can indicate the number of minutes until the screensaver should activate. It has nothing to do with DPMS.
Of course, all of this can also be activated "on-the-fly" by using xset. If you don't have access to your system's XF86Config file, a good place to put these commands would be in your ~/.Xsession or ~/.xinitrc file.
bash$ xset -dpms # Disable DPMS bash$ xset +dpms # Enable DPMS bash$ xset s off # Disable screen blanking bash$ xset s 150 # Blank the screen after 150 seconds bash$ xset dpms 300 600 900 # Set standby, suspend, & off times (in seconds) bash$ xset dpms force standby # Immediately go into standby mode bash$ xset dpms force suspend # Immediately go into suspend mode bash$ xset dpms force off # Immediately turn off the monitor bash$ xset -q # Query current settings
If instead you're using the Linux console (not X-Windows), you'll want to use setterm(1):
bash$ setterm -blank 10 # Blank the screen in 10 minutes bash$ setterm -powersave on # Put the monitor into VESA power saving mode bash$ setterm -powerdown 20 # Set the VESA powerdown to 20 minutes
Here's what I've tried, with no success: 1. Deleted acpi RPM package (didn't think this would have anything to do with behavior; it didn't). 2. Commented out xorg.conf Option "dpms" in Monitor section. 3. Deleted xorg.conf Option "dpms" in Monitor section. 4. Typed Option "dpms" "false" in xorg.conf Monitor section. 5. Typed Option "DPMS" "false" in xorg.conf Monitor section. (Case sensitive?). 6. Typed Option "dpms" 0 0 0 in xorg.conf Monitor section. 7. Edited /etc/gdm/-all- Default shell scripts (Init, PostLogin, PreLogin, PostSession): 7a. Included xset -dpms 7b. Included xset dpms 0 0 0 None of those worked, and every time, Xorg.0.log has: (II) Loading extension DPMS (II) SAVAGE(0): DPMS capabilities: StandBy Suspend Off; RGB/Color Display (**) SAVAGE(0): DPMS enabled Is it possible the S3 Savage driver has DPMS enablement hardcoded? Any ideas how to get DPMS disabled?
In the KDE Control Center, drill down through Peripherals, Display, to the Power Saving tab. Check the Enable Power Saving checkbox and set time for "Switch Off Monitor." In a non-KDE environment, find "Display Power Management." That's what automatically turns off DPMS when the system is idling.
DPMS (Display Power Management Signaling) is a standard from the VESA consortium for managing the power supply of video monitors for computers through the graphics card. The most common use is to shut off the monitor after the computer has been idle for some time.
There are multiple settings that influence monitor power savings:
- xorg.conf: The monitor section can contain a DPMS option:
Section Monitor ... Option "DPMS" ... EndSection
- xorg.conf: The ServerFlags section can contain a NoPM option:
Section "ServerFlags" ... Option "NoPM" "true" ... EndSection
- xset can be used from the command line to turn DPMS on/off:
xset -dpms and: xset +dpms
- KDE sometimes has a control panel for power management where DPMS can be selected.
- Often the BIOS also has options for power management
But probably DPMS will work if you add the DPMS option to the Monitor section and make sure that the NoPM section is not placed in ServerFlags. You can also add the following lines to ServerFlags in order to control when the display should be turned off:
Section "ServerFlags" ... Option "StandbyTime" "1" Option "SuspendTime" "2" Option "OffTime" "3" ... EndSection
Screen goes blank but returns when mouse is moved or keyboard is used
Edit your /etc/X11/XF86Config-4 or /etc/X11/xorg.conf file, and look for:
Section "ServerFlags" #DontZap # disable <Ctrl><Alt><BS> (server abort) #DontZoom # disable <Ctrl><Alt><KP_+>/<KP_-> (resolution switching) AllowMouseOpenFail # allows the server to start up even if the mouse doesn't work
Option "blank time" "0" Option "standby time" "0" Option "suspend time" "0" Option "off time" "0" Option "NoPM" "1" EndSection
Also, look for:
Section "Device" Identifier "device1" VendorName "nVidia Corporation" BoardName "NVIDIA GeForce 256 (generic)" Driver "nv" Option "DPMS" EndSection
In this case, you would need to either delete the Option "DPMS" line, or change it to # Option "DPMS" to comment it out. The next time you start XFree this change will take effect.
Section "Monitor" Identifier "monitor1" VendorName "Plug'n Play" HorizSync 30-85 VertRefresh 50-160
# Sony Vaio C1(X,XS,VE,VN)? # 1024x480 @ 85.6 Hz, 48 kHz hsync ModeLine "1024x480" 65.00 1024 1032 1176 1344 480 488 494 563 -hsync -vsync
# TV fullscreen mode or DVD fullscreen output. # 768x576 @ 79 Hz, 50 kHz hsync ModeLine "768x576" 50.00 768 832 846 1000 576 590 595 630
# 768x576 @ 100 Hz, 61.6 kHz hsync ModeLine "768x576" 63.07 768 800 960 1024 576 578 590 616 EndSection
Ensure that there isn't an Option "DPMS" in the Monitor configuration.
Configure XOrg to use DPMS.
Section "Monitor" Option "DPMS" Section "ServerLayout" Option "OffTime" "20"
If you use nvidia-drivers you need to add the following to the "Device" Section.
Option "DPMS" "TRUE"
The DPMS standard (Display Power Management Signaling) was developed to extend the useful life of PC monitors as well as to conserve the relatively high amount of energy used by monitors when not required.
The DPMS compliant video controller and the DPMS compliant monitor use the Horizontal sync and Vertical sync signals to control the power mode of the monitor. Because there are 2 signal lines, it allows 4 modes of operation. Normal, Standby, Suspend and Off. The DPMS compliant video card will toggle the sync lines on or off to select the power mode and the monitor will react as follows:
|OFF||ON||Standby---RGB guns off, power supply on, tube filaments energized, (screen saver mode)|
|ON||OFF||Suspend---RGB guns off, power supply off, tube filaments energized.|
|OFF||OFF||Pwr off----Small auxiliary circuit stays on to monitor the HS/VS signals to enable power on when data needs to be displayed on the screen.|
Typical recovery times. (Picture on screen)
|H-sync||V-sync||Power used||Recovery time|
|OFF||ON||<110 watts||2-3 secs|
|ON||OFF||<15 watts||2-3 secs|
|OFF||OFF||<5 watts||8-10 secs|
* The actual wattage will vary with the screen size of the monitor.(14/15" = 85-100W----16/17" = 95-120W----20/21" = 110-140W )