Hi.
I have just recieved a new U2415 (manufacture date August 2014, revision A00).
All has been fine with the monitor until i turned it off when I went out.
When i turned the monitor back on again the text was very distorted with lines across the screen. While in this state the display turned off and on every few seconds (could be 1 second or could be 10 seconds).
Rebooting the PC has the monitor working again until you turn it off and the same issue occurs. This is 100% repeatable.
The system this occurs on is an i7-860 with MSI P55-GD85, 16GB RAM and EVGA GTX750Ti.
This issue occurs with the supplied DP to mDP cable (DP on GPU, mDP on the monitor). I have also tested it with a DP to DP cable I received with a P2314H and this also has the same issue.
The issue does NOT occur with HDMI nor does it occur when switching the monitor to DP1.2 however when using DP1.2 there is no display when powering on the PC until it reaches windows therefore this is not a solution but a work around as it is a bit useless if needing to access the BIOS.
Also the issue does NOT occur in DP1.1 mode in the BIOS. The monitor can be turned off and on in BIOS fine, this issue only occurs once windows has loaded (I don't know if it occurs whilst windows is actually loading due to the wonders of SSDs :))
I have also tested the monitor on a second PC running an Intel DH77DF (H77 mini ITX board) with 8GB RAM and an i5-3470S using the on board Intel HD2500 GPU. The issue does NOT occur on this system in UEFI/BIOS, Windows or Linux/Fedora 21 KDE.
The windows version used is Windows 7 Home Premium on the mini ITX/Intel GPU system and Windows 7 Ultimate on the PC/nvidia GPU system.
Just for extra testing the fault occurs with DDC/CI enabled as standard and Fast mode enabled.
I have also tested this with the Dell monitor driver installed and without, same both times.
I'm guessing this looks like compatability with nvidia hardware and/or drivers and the monitor?
Is there any way to get around this other than using HDMI or DP 1.2?
Thanks
*edit*
I've also tested this in safe mode on the nvidia machine where the issue does not occur and also with a Fedora 21/KDE live boot disc which was also fine.
Same when changing the monitor to 5:4 mode. Oddly, changing resolution in windows to something like 1600x1200 doesnt reproduce the issue when turning the monitor off but ALL 16:10 resolutions do. (although at 1600x1200 sometimes the display will be distorted but turning off and on again resolves that).
I've also taken a few pictures to try show but I don't know if you can see much
Pic 1
Pic 2
Pic 3