I bought this monitor last year and have tested VGA, DVI, and Mini DisplayPort and those work. I don't have a cable to test HDMI, but my initial plan was to use DisplayPort. I bought a certified DP cable Accell UltraAV 3m/10ft B088C-010B cable to test the DisplayPort and it is not working. The display just says it will go to powersave mode in 5 minutes.
I know for sure the DisplayPorts on my videocard are all working. The monitor works fine with the included DisplayPort to Mini-DisplayPort cable. The revision on this monitor is REV A04. I have tried setting the monitor to DisplayPort 1.2 and that doesn't work either. Do I have a defective DisplayPort?