In my case, whenever I try a new BIOS or new driver, I then set the monitor turn off time to 2 minutes or 5 minutes or whatever for testing purposes.
Then I let the laptop sit on the Windows desktop for a few minutes until the screen turns off.
Then I try to turn the screen on by touching the trackpad, pressing a key on the keyboard, or pressing the power button.
It never works, and I have to hold the power button to turn the laptop off.
Then I set it back to never turn off the display.
Then I test sleep/wake by closing the lid, making sure it entered sleep mode, then opening the lid and making sure it wakes up. This works without issue.
The display off and on functionality used to work as expected, back in late 2017 / early 2018. But some time in 2018, it stopped working. My guess is it's either some Windows 10 update, some driver update, or some incompatibility between the two.
I have also testing enabling the USB wake functionality in the BIOS as well as changing the battery charging mode to Standard instead of Adaptive.
This issue was temporarily resolved when we set up a new local admin account.
Please create a local admin account by following this link & check if the issue persists.
I'm having the same problem (Screen hibernating and not waking up even though mouse and key board is active and power button is white) as of about 6 months ago on my Inspiron 23, Model 5348, but I figured away to activate the screen without rebooting (most of the time).
On my all-in-one screen based PC, there is a button above the power button on the right side of the monitor which cycles the monitor interface between HDMI and PC. I cycle through this one time (PC->HDMI->PC) and the screen turns on.
Here are my PC details:
Any further info on this or how to fix it?
I can check if a new user profile fixes it for testing purposes, but I won't be able to do so for some time (weeks or months) as I am away from that laptop. I'll report back when I can, but even if a new user profile fixes it, I would hope Dell is looking into the actual cause in order to find a permanent fix, and hopefully one that can be applied to existing user profiles.
We were able to fix this with a temporary local admin account.
This has been escalated to our product team & they are working on this. There is no issue with the hardware here as the system works fine with a new account.
I am afraid, we do not have an ETA on this & not sure when the update will be available. If I get an update in a couple of days, I will update on this thread.
Yes. I have changed the amount of time the monitor stays on during inactivity. I have not changed the sleep mode because I don't want this computer to go to sleep. If it does, I cannot access the media server, remotely.
FWIW, uninstalling the driver and reinstalling it at start up seemed to work temporarily but the problem came back. Right now, I've changed the power and display settings so the computer does not go to sleep and the monitor does not turn off. I don't think this is a great option because I worry about screen burn and of course, I only need the monitor on when I'm using it.
In the meantime, I manually put the computer into sleep mode, overnight but when I awoke this morning, it would not wake.
 I wonder if something woke it, during the night....like the dog bumping into the cabinet it rests on, moving the mouse and waking the machine. If this is the case, it then went to sleep on it's own and cannot come out of sleep mode so, unlike brianms, I don't know if manually putting it to sleep resolves the problem. Also, if a simple move of the mouse can wake it, even that doesn't seem like a good temporary solution.
Any word on a fix? I really hate to leave my monitor on, 24/7 but when letting it go to sleep means I have to force a shutdown, there's really no better solution....not to mention that I can't gauge whether or not my current tasks are working, which means that forcing a shutdown means losing data or progress.