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Ubuntu 1904, both X and Wayland. AMD 2400G, ASUS motherboard with 3 screens: HDMI,VGA,DVI.

When I leave my computer, it will blank the screen after the timeout, then my 3 monitors will fall asleep, but they will wakeup after 10 seconds or so, and never enter power save mode again. They will keep showing the lock screen.

So it is a costly affair, burning 100 Watts, and shortening lifespan of my screens.

Also when I turn off my screens manually:

xset dpms force off

They turn off, and wake up after 10 seconds.

Could be this bug 1292041. But I doubt because it's is also happening when powering off the screens with xset.

How do I get my screens to enter powersave mode?

Janghou
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2 Answers2

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WORKAROUND

Change the setting of your monitor from input select: auto to a fixed input, e.g. hdmi.

Here, with a AOC Q3279VWFD8 (WQHD):

OSD -> extra -> input select -> hdmi (was auto)

That fixed my problem, also that setting prevented my other monitors from entering powersave mode (turning off). It seems a monitor can poll the graphic card through HDMI (CEC?), preventing powersave mode. Probably cable type plays a role as well.

Still I consider this a bug, IMHO powersave mode should work with default settings of monitors.

Janghou
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  • My Philips monitor didn't presented such an option to fix the input selection. Though changing the OSD Time Out to 5 seconds also resolved the issue in my case. – Rodrigo Oliveira Dec 18 '20 at 17:06
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    Glad that helped. Should we file a bug? – Janghou Dec 22 '20 at 08:08
  • If there isn't any already open, yes. I just haven't got the time yet to search for it. Would you check it and open it? If you do add the link to the bug to your answer and I'll subscribe to it. – Rodrigo Oliveira Dec 22 '20 at 10:57
  • Not sure against which package I should file it. Not the gnome-screensaver package. – Janghou Dec 28 '20 at 20:09
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Only thing that helped was turning off the automatic screen lock. even if the monitor was set to auto=off , and hdmi selected, the problem still happened after manually locking the screen, it came back on in about 5 seconds by itself and left all the connected monitors on too.

nkshirsa
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