I have the same problem as here. P2416D blinks randomly every few minutes, and happened continuously for almost 2 months now. I have changed the HDMI cable cause I was thinking it was a bad cable problem. But cable itself is fine, and not the issue here.
I also installed the DDM software since you mentioned it could help. I can see the brightness changing to different modes for different programs, but P2416D still blinks from time to time (made me very annoying). I would NOT use VGA or Display port because my laptop (HP Spectre X360 ultrabook) only equipped with HDMI (and mini Display), and I have multiple HDMI cables available. Since both my laptop and P2416D have HDMI port, It's not worth the hassle to get another cable or adapter to try mDP at all. By the way, my previous monitor worked well with my laptop. It's definitely not my laptop's problem. HDMI connectivity was one of the major reason why I chose P2416D. No matter what, HDMI on P2416D should not give you this annoying blink all the time.
Could Dell please offer some solution regarding to this problem? It seems like not just me but many people having the same problem. Installing DDM software is not the solution obviously.
