DPMS not working in 4.5

Duncan 1i5t5.duncan at cox.net
Sat Aug 28 09:26:04 BST 2010

gene heskett posted on Fri, 27 Aug 2010 23:22:19 -0400 as excerpted:

> It did not survive the reboot, so I've "xset dpms 250 300 600" and will
> test shortly by leaving it alone once I get caught up with the email.
> Where, if kde (or the pclos versions of drakex) cannot set for a
> default, is there some place in the /etc/X11 tree where I can add or
> change this so it works automatically when x is started?

OK, so you can at least use xset to verify the settings, and to set it 
each time you restart X (it's an X setting, so restarting X will normally 
make it reset, no full reboot needed).  That's progress. =:^)

I don't know much about PCLinuxOS except that it's based on Mandriva, 
which I haven't used since I switched to Gentoo back in 2004.  But the 
generic X and KDE stuff will likely apply.

First point: Altho they're sometimes set in the same places, DPMS and 
screensaver settings are logically separate, from X's perspective.  That's 
why xset lists them separately.

On modern display hardware, generally LCDs of some type these days, but to 
a lessor extent but still true to some degree, on half-modern CRTs as 
well, the "warm-up time" time the display used to take to come back to 
life is almost non-existent.  As such, screen savers as such are generally 
an anachronism, unless you happen to prefer seeing the screen still active 
and don't care about the additional power use vs simply having them turn 
off.  Similarly, it seems a lot of monitors return fast enough from full 
suspend mode, which is low enough power they don't even have an off unless 
you physically switch them off, that they've basically done away with 
standby as well.  The result is that DPMS standby/suspend/off often mean 
the same thing, and the monitor will enter suspend) at the first timeout, 
traditionally standby.

At least, that's what I've observed here, on quite a lot of hardware.

Meanwhile, note that unlike CRTs, LCDs (particularly desktop models, 
laptop models are a bit different due to the battery constraints they work 
under) often use very nearly the same energy in "on but screen blanked" 
"black" state, as they do in full-white state.  This is because the lamps 
powering them often remain at full power as long as the monitor is on, 
with "black" simply meaning the LCDs are set to full opaque mode, letting 
virtually no light thru.  (Laptop displays and desktop units with "dyanamic 
contrast" are often exceptions to this, turning the lamp down for dark 
scenes, as an all-black display obviously is, both reducing power usage 
and resulting in a higher "dynamic contrast" rating.)  So again, even a 
screen-blanking screen saver may not actually save any energy over simply 
leaving the thing on, and LCDs generally don't have the burn-in problems 
of CRTs or plasma displays, so yet again, either simply leaving the thing 
in normal operating mode, or going ahead and triggering full suspend, is 
generally the way to go.

Of course, those with a reason to use a console locker (enter password to 
resume) may still want to run a screen saver for that, since that's the 
timeout mechanism used there, but again, that's an entirely separate 
function from the display suspend/power-down functionality.

Now that /that's/ dealt with...

There's two ways you can automate your DPMS settings.  One is using the 
normal xorg.conf, or a file with the same DPMS settings dropped in 
xorg.conf.d if you're running xorg-server 1.8 or higher.  (FWIW, 1.9 just 
came out a few days ago, and that's what I'm running now.  I upgraded from 
one of the release candidates, which I'd been running for a few weeks.  
The xorg.conf.d directory makes things MUCH simpler! =:^)

The other would be simply sticking a bash script in your kde startup, that 
automates the xset stuff you're using now.

Let me know which way you want to go, and if you want to try the xorg.conf
(.d) method, the version you're running and whether you already have a 
config or are going "xorg.conf-less" at present, and we can take it from 
there.  (This assumes of course that whatever proprietary drivers you 
might be running use the standard xorg.conf options... I don't do 
servantware, see the sig, so I'll help you if it's standardized, if not, 
you're on your own or find help from someone else.)

Or, if you know anything about shell scripts, you can likely figure out 
the xset thing on your own, and similarly with xorg.conf, if you know 
anything about it, or know how to read manpages and/or your nvidia driver 

Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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