Forcing display sleep on DP monitors?

nicky9499 · March 16, 2022

G'day gents,

Recently I bought an LG 32GK850G. It accepts DP and HDMI (1.2) but I went with the former to take advantage of 1440p at 144hz. This is my second DP monitor, the other being a Viewsonic 32" 1440p on another triple-screen setup that I've used for over a year without any issues. I can turn if off and on at any whim, it doesn't affect the desktop or any windows be they open or closed. Therefore, this is my first time learning about this annoying thing called DDC, wherein certain DP monitors will totally drop off the grid as far as Windows is concerned after powering off, and because I run multi monitor, this throws the entire desktop into chaos. Every. Single. Time. Open windows are resized, minimized windows are crammed into the other monitor. Icons are scattered. It's a royal mess.

Now the LG has "deep sleep" setting.

When enabled, it drops out permanently, leaving the other monitor (in portrait mode) with a rotated desktop since Windows now treats that as the primary display.

When turned off, it drops out momentarily, the portrait monitor gets messed up for a second, but is then re-detected. However the desktop is already trashed.

Either way, LG's implementation of DDC or sleep mode appears to be garbage.

Today, I noticed Windows going to "display sleep" while idle and both monitors showed "entering sleep mode" before turning off!

When I wiggled the mouse, the desktop was exactly as I left it.

However, sometimes I have to leave 3D programs running, and they appear to prevent this "Windows-initiated sleep mode".

Setting the display sleep timer (or even screensaver timer) to 1 minute does nothing.

I also tried THIS and THIS, both of which appear to do the same thing and have the same result - it works for two seconds, then both monitors wake right back up.

Question:

Is there any way to FORCE Windows to put displays to sleep regardless of whatever is running in the background?

Side note: this is Windows 7, but it will be upgraded to dual boot with Windows 10 next week, so ideally the solution would work on both but more importantly W10.