R9 270X Displayport problems

So this is the card that I'm using currently.


I was using the displayport connection to my monitor while I was using Windows 7, but then I upgraded the OS to Windows 8.1 and when the computer went into sleep mode or hibernate mode the displayport stopped working completely. I can still use it on HDMI, which is what I'm doing right now but I want to know how to get the displayport working again. Anybody got anything on this?