U3011 via DisplayPort "forgets" it is Hi-Res, Drops to 640*480

David Lean,

Since DP (DisplayPort) is both video and audio, I am wondering if your computer is somehow allowing them to enter some power save mode which is then causing the monitor to not be seen? For example, a network card has a Power Management tab in the device manager. There is an option in there to "Allow the computer to turn off this device to save power". Since the U3011 uses the computers USB port, audio, and video card, you need to find all three of those and make sure they are not being "turned off" by the computer.

I do not believe it is a Power management feature as that would not persist between reboots. Also I'd expect it to affect both screens at the same time & not just the one connected via DisplayPort. 

NB: I'm running Windows Server 2012 (installed over a freshly reformatted drive with nothing but the OS installed.). I've also tried a fresh install of Windows 8 but did it didn't fail in the 2 days I was running the test. (which proves nothing as sometimes it is OK for longer than that. )

I did get the following error earlier this week

"DisplayPort Link Failure
The system has detected a link failure and cannot set the requested resolution and refresh rate on your DisplayPort display. Your display might not support the requested resolution or there may be an issue with the cable connecting the display to your computer"

So as my cable is 3meter, I've swapped it out for a 2 meter one, to see if that makes a difference.

Thanks for your thoughts

I'll keep trying to narrow it down.

danblake,

Try toggling DDC/CI off, then on in your monitor OSD (On Screen Display) to see if it helps.

Thanks.   Tried toggling DDC/CI off. Still same issue.   Noticed that if I powered monitors off then the resolution and refresh rate would stay correct, even though I'd still get the error message.   Went in to power management and stopped monitors from going into standby.  Now they keep correct resolution and refresh rate,  though again I still get the error messsage.

Duplicate Post - Sorry!

I have a similar problem on a U2713H. I did not have it on the U2408WFP it replaced. What was the solution to the OP's problem?

I tried turning on and off various energy and power management features but nothing changed the behaviour. The monitor will sometimes display the proper resolution when the computer comes out of standby but not every time.

Problem definition

DELL Hi-Res Monitors fail to wake correctly from Power saver mode, They indicate their Max Screen resolution is 640*480. 

1. This issue seems to be related to using DisplayPort interface on the newer model DELL displays. ie U27.. & U30..'s
2. It is possibly associated with the quality &/or length of the DP cable. I say that because the problem occurs more often with my rightmost U3011 which is connected via a 3m cable. The other screens use a shorter 2m cable. And it is not the specific monitor as I've swapped them around in order to isolate the issue. Note: I'm using really high quality cables. & have tried a few from different vendors. So I suspect a timing or signal strength issue.

Problem resolution(s)

1. Remove power from the monitor for 30 secs. ie: Turn it off at the wall or physically pull the cable out of the back of the monitor. Pushing the blue power button on the screen is NOT sufficient.  (This is not always necessary, but always works)
2. Sometimes you also need to change the screen resolution on windows, which is easy if it is not your only monitor.

Other suggestions. 

1. Avoid the problem. Disable the Power saver mode. in your OS (ie in Windows, OS/X) or linux. Instead turn the power off (blue button) when you step away from your desk.). NB: This will also power off the screens USB ports, so don't plug your external disks into your screen's USB ports  if you take this approach.

2. Occasionally you can solve the problem just by changing the Screen resolution in Windows. For Multi-monitor display. Set it to "Disconnect this display" Hit OK. Then "Extend desktop to this display" & if you are lucky, You'd be able to change the resolution to normal. If not power off. & repeat.

3. I've not explored the option of using the On-Screen display (OSD) to set the DDC/CI feature to disable. Nor have I tried disabling the Audio Power saver feature. These may be relevant. as DisplayPort & HDMI both carry Audio as well as Video. Yet these Monitors do not use the Audio signal. It is possible that something is causing them to not wake up properly.

My 2 U3011s are working better without plugging anything into the USB hub on either - but I still have issues with the following:

1. Changing resolutions on one or both after wake-up
2. Windows migrating to the Upper Left of Left monitor and making themselves all the same size
3. Occasionally a monitor that won't wake up at all and I have to unplug it to bring it back

I'm using 2 Accell DP cables to my monitors. Supposedly these cables don't have pin 20 connected and are VESA compliant but I've yet to probe them.They are these IIRC: http://www.accellcables.com/B143B.html

Other config items: Asus P8Z68 Deluxe Pro, Core i7 2600K unlocked,  Windows 7 Pro, 16GB, Video: Asus 2GB HD7870 with this software:

Driver Packaging Version    12.104-130328a-155980C-ATI
Catalyst Version    13.4
Provider    Advanced Micro Devices, Inc.
2D Driver Version    8.01.01.1295
2D Driver File Path    /REGISTRY/MACHINE/SYSTEM/ControlSet001/Control/CLASS/{4D36E968-E325-11CE-BFC1-08002BE10318}/0000
Direct3D Version    9.14.10.0969
OpenGL Version    6.14.10.12217
Catalyst Control Center Version    2013.0328.2218.38225
AMD Audio Driver Version    7.12.0.7714

I found this article helpful for the window resizing  answers.microsoft.com/.../1653aafb-848b-464a-8c69-1a68fbd106aa