For several years spanning multiple previous releases of Fedora (running KDE instead of Gnome), I've been able to use the following script to force my display to standby:

sleep 5
xset dpms force standby

Now, running Fedora 25 Workstation 64-bit with KDE, this script no longer works. (Fedora 25 with KDE uses Xorg, not Wayland). The display goes dark, but within 30 seconds it comes back on. The script produces the desired result on the same PC with Ubuntu 16.10.

Note: On the previous releases my PC had an AMD processor and I was running the 32-bit version of Fedora. Concurrent with my upgrade to F25 64-bit was a switch to an Intel processor.

One solution I'm aware of is to put the above script into a loop. Can someone suggest a better solution?