Mikeserv Support Forum

While I was sitting in front of my machine my Sceptre display (the better one) suddenly went dark and wouldn't wake up, while the Asus display next to it was fine. I unplugged it from its power brick and plugged it back in, made no difference. So assuming it was finally done, which seemed like a safe assumption because it was a Sceptre, I dug out my other Sceptre (the one that doesn't wake from sleep half the time) and hooked it up, and it was the same thing. So it didn't seem to be the display's fault. I rebooted and all was back to normal. I swapped the better Sceptre back in place. Not sure what happened.

Sounds like there was nothing to power the port on the graphics card back up, until reboot. Typical display power management fuckery.

It just did it again, this time it failed to wake from sleep. Unplugging the power and replugging it made no difference. I was in the same distro as the last time, CatchyOS. A different session didn't help either (just logged out and back). I knew it likely wasn't the display since it previously did the same thing with the other Sceptre. I decided to try moving it to a different DP port on the card, and while I was back there about to do that I heard the disconnect/reconnect sound in Plasma multiple times, but the screen stayed off. I changed it to a different port and at first it still remained off, but then I noticed it was on. Maybe it developed a faulty port.

So this time rebooting or powering off the computer didn't fix it?

That may have worked, it did the first time, this time I just tried logging out and back, and then moving it to a different port on the card.

It's possible that power management fucked it up and it doesn't reset until the driver does, or something.