I have a dell latitude laptop and I have two dell P2412 display connected to it through the dell docking station. One monitor is connected through the HDMI port and the other is connected through the VGA port. The one that is connected to the VGA port will not wake up after the system goes to sleep. I have to cycle the power 3-10 times before it finally wakes up and picks up the signal from the laptop. I have tried making that display the main display and that did not help. I tried changing the power setting to never go to sleep. Not sure what else I can try to fix this problem.
Swap the P2412Hs on the ports used on the dock. If the same issue happens with the other P2412H now on the VGA port, the fault is not with the P2412Hs. The fault is either the dock or the laptop. If so, test each P2412H directly to the laptop. If the "wake up" issue does not appear, the fault must be the dock.