I have an XB241H G-Sync monitor. It works perfectly when using HDMI...
but with Displayport, it works fine when freshly powering up the computer. It works fine when waking up from hibernation....
but when waking up from sleep, which is my preferred method, the monitor will power up, the splash screen will pop up, then "no signal"... The PC is on, as it can play music and if I plug in a different monitor, it's working...
I have tried the following:
lowering the Hz
swapping DP cables
using High performance mode
turning off link state
making sure connections are tight
switching to different DP ports on my GTX 970