Wake up monitor from standby and show the screen without blocking further standby [Ubuntu 16.04]

Question

After some time the monitor goes to standby mode. I want to wake up the monitor by a shell script. I already can wake up the monitor itself by xset -display "$DISPLAY" dpms force on. But I only see a black screen with the mouse pointer. And as side effect it does not go to sleep after another couple of minutes.

What I want is to wake the monitor and Ubuntu like when I move the mouse or press any key but without really doing this! So xdotool is not a solution. I see whats going on on the screen and after some minutes it goes to sleep again.

How to get this done?

Solution

The only thing I could find on your situation was this webpage (Can't wake up monitor once dpms put it into sleep) from Archlinux. It's a long read but at the very bottom one poster recommends your script say this:

sleep 1 && xset dpms force standby && sleep 8 && xset dpms force on

Note this user tip implies it is based on having turned off DRI3 in /etc/X11/xorg.conf.d/20-intel.conf and using DRI2:

Section "Device"
   Identifier  "Intel Graphics"
   Driver      "intel"
   Option "DRI" "2"
EndSection

Please note this is the best I could come up with for your problem and felt compelled to post it because there have been no other answers. Since I can't reproduce your problem I have no idea if it will work for you as it has for others.

If it doesn't work I encourage you to google as much as you can using appropriate keywords.

Comments

[WinEunuuchs2Unix]

Do you have wired USB keyboard and mouse?

[Michael]

Yes. I'm currently trying a solution by using the mouse using xdotool. But this could cause side effects.

[WinEunuuchs2Unix]

I've favorited your question and will try to look at xdotool tonight.

[Michael]

xdotool works. The side effect: It is a user input. I need a solution that doesn't use mouse or keyboard.

[WinEunuuchs2Unix]

I took a quick peek at xdotool. It's not a package I want to install and learn. Hopefully someone else here is using it and can provide support, alternatively you might want to post your question to the developer (if possible).

[Michael]

Still no solution for this. I searched now for DBus signals. Thought there would be a wake signal or something. But didn't find one.

[WinEunuuchs2Unix]

I posted an answer below and would like to know if you've had a chance to try it.

[Michael]

As it is a generic OS image for different PC hardware this is not a way I want to go.