Dell U2711 x DisplayPort Issues in Sleep mode

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tami

Lifer
Nov 14, 2004
11,588
3
81
I've got a strange question with my dual Dell U2711 monitor setup which is hooked up to a Radeon HD 6950 derivative: one is connected to the dual-link display port at 2560x1440, and the other is connected to DisplayPort at 2560x1440 because I can't get 2560x1440 on DVI with two displays.

Dell acknowledged to me about a year ago that the U2711 doesn't work well with DP configurations. This was in Twitter over a direct message with them basically saying "there are issues with DisplayPorts", so I didn't get enough clarity nor do I know if I can address this as well as I'd like or even at all. That's why I'm coming to AT for more qualified experts to help ;)

The issue seems to have some OS specificity. For example, I was on Windows 7 until last month, and normally, the monitor would go to sleep after 1 minute and then wouldn't power on. I'd end up rebooting the PC to get the computer to "kick" the monitor awake again.

In February, I upgraded to Windows 8. Now, the problem manifests itself completely differently and far more often: the DP connected monitor doesn't always power off. It dims, sometimes displays colorful squiggly lines as if the monitor is broken. Sometimes it looks like a black screensaver is on (the monitor screen is powered on, rather than off). Sometimes only about 50% of the screen is dimmed and the rest is visible "behind the dim." I can provide pictures if need be. I'd say the power-off in monitor-sleep mode is hit or miss; 60% of the time, it exhibits the behavior I described - 40% of the time, it powers off as I desire.

Does anyone know a way around this, save for buying a new video card or upgrading my U2711? I like having two identical monitors with identical resolutions, so I'm not really keen on that idea...
 
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tullnd

Junior Member
Jan 22, 2005
13
0
61
Hi. I have two U2713HM's. Not the same monitor, but also has some issues with DP.

I'm running mine off a Sapphire 6970. Both of mine are running off DP.

I was using Monoprice mini-DP to DP cables previously on my HP ZR24W's that worked fine. When I switched, I started having issues where it wouldn't detect the resolution correctly. One would sometimes load up right, the other only at 1920x1080 max. Sometimes unplugging and reconnecting would fix it. Mostly I had to reboot.

I replaced the monoprice cables(they allowed me to exchange them even at almost 2 years old), and it didn't help. Finally, I saw some info about DP 1.2 cables being the issue. The monoprice cables I had are only 1.1 officially.

I bit the bullet and ordered some actual 1.2 cables, at a rather high $25 for the pair. However, it worked. No more weird resolution issues.

I had only twice experienced the screen NOT waking from sleep. I've only experienced it once since I switched the cables over...and it resolved by simply powercycling the monitor quickly...and I think changing the input would have worked too(powercycling the screen is faster though). I let my computer both sleep and hibernate often, and I have only experienced it once in the 3 months I've had these using the new cables.

You may want to give some 1.2 cables a try.

I used the Accell B143B-007J cables. 6.6feet long. Also available at 3.3feet. These are actually on the official certification page for DP 1.2.

There are a LOT of DP1.2 cables out there for less, but I needed mini-DP 1.2 to DP 1.2 and that was a bit harder to find.
 
3

3DVagabond

Lifer
Aug 10, 2009
11,951
204
106
There are a lot of cables out there that don't follow the spec. Accell do and have cleared up issues for a lot of people.
 
U

_UP_

Member
Feb 17, 2013
144
11
81
If you are going to try the cable, there was a whole thread about the non-VESA compliant cable here. I remember reading it a while ago.
They suggested trying to block pin #20 on the cable (as that is the issue with most cables). In one of the last posts, they link this page, that shows how to do it. You might as well give it a go before getting a new cable. It just might do the trick. Good luck!
 
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tami

Lifer
Nov 14, 2004
11,588
3
81
_UP_ said:
If you are going to try the cable, there was a whole thread about the non-VESA compliant cable here. I remember reading it a while ago.
They suggested trying to block pin #20 on the cable (as that is the issue with most cables). In one of the last posts, they link this page, that shows how to do it. You might as well give it a go before getting a new cable. It just might do the trick. Good luck!
Click to expand...

Interesting, thanks. I actually plunged and bought the cable, but no worries - I have this troubleshooting step at my disposal too. I'll definitely see if that's the way to go. Thanks!
 
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tami

Lifer
Nov 14, 2004
11,588
3
81
@james1701 - yes! And the Accell cables didn't work. Really bummed right now :(
 
james1701

james1701

Golden Member
Sep 14, 2007
1,791
34
91
I am using the Accell cable too. I went back to the dual link DVI, and everything works great.

I did have trouble when we were on the 13 series driver with insane flicker even with the DVI-D. The 14's have eliminated that, and everything works great on DVI.

So disappointing.

I am curious if we could ask for an RMA on these cables and if that might fix it? I sent them an email asking their advice. At least it proves the monitor is not bad.
 
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T

tami

Lifer
Nov 14, 2004
11,588
3
81
I'd love to use DVI, but it's a dual-monitor setup and the second monitor's resolution would go down to 1920x1080. This monitor supports 2560x1440. I can't lose so much resolution...

I'm quite confused by this. Seems like it could be an OS issue (it was better with Win7 but bad with Win8) then... why is it not behaving properly with Windows 8?
 
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tami

Lifer
Nov 14, 2004
11,588
3
81
Yeah, the second DVI scales down, as does HDMI. 1920x1280. ugh. I'm stuck with DP and it's crap.
 
D

dn7309

Senior member
Dec 5, 2012
469
0
76
what advantage do you get for using Display port when DVI is available for the same performance?
 
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tami

Lifer
Nov 14, 2004
11,588
3
81
@dn7309 see, that's the thing - it's not the same performance. Please read the post in its entirety as I addressed this point three times, and in fact, it's mentioned in the first sentence of the post.

Here's the fourth attempt to clarify why dual DVI with my particular card (also linked twice in the thread) does not work on a dual monitor setup:

DVI connection 1: 2560x1440 resolution
DVI connection 2: 1920x1080 resolution. Can't go higher. I have two monitors with identical 2560x1440 resolution. I'm not willing to lose so much resolution. It's simply not acceptable to me.
 
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tami

Lifer
Nov 14, 2004
11,588
3
81
[I was wrong. The observations I wrote about here are incorrect.]
 
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jefbak

Member
Sep 5, 2004
47
0
0
My U2711 just had a problem like this where the displayport suddenly stopped working. I ran across a dell forum response that said to remove the USB upstream cable from both the monitor and the PC if it was connected. I did that, the displayport connection started working again.
I went though a lot of testing different cables and connections before I came across that suggestion... ugh. http://en.community.dell.com/support-forums/peripherals/f/3529/t/19567748.aspx
 
james1701

james1701

Golden Member
Sep 14, 2007
1,791
34
91
I'm trying removing the upstream USB now. It may take a day or two to manifest itself, so I can't claim it a fix yet. I did have trouble with pages like Google flashing and flickering for no reason. So far, that has not started yet. I'll keep my fingers crossed and report back in a few days. I hope this fix works.
 
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Bull Dog

Golden Member
Aug 29, 2005
1,985
1
81
my first Dell U2711 purchased in March 2011 ran just fine on DisplayPort for years. Never had a single issue....even in Windows 8. Then back in January 2014 I decided to take advantage of my three year no dead pixel warranty and get the stuck pixel on my U2711 replaced.

Now I'm having the same "display not turning off properly" issue with my new U2711's DisplayPort....
 
james1701

james1701

Golden Member
Sep 14, 2007
1,791
34
91
I may have accidentally found a solution. I made two changes with one being the more likely culprit.

First, we used to use the flags settings in Chrome to disable hardware acceleration. That disappeared a while back with only a few remnants of those flags remaining. I was looking in the Chrome settings advanced section there is a area labeled System. There are two check marks. I unchecked the use hardware acceleration when available tick.

The second possibility has to do with Windows themes. I had always chosen my own background. I was messing around with the default themes, and downloaded a few from the link and used several of those. I am on Windows 8.1, but there could be a bug in the Windows code.

I made both changes the same evening. For the last two days, I have not had a single instance of the sleep problems with my monitor linked in my videos I made. Someone else might want to give one or both of these a shot, and report back if that helps.

Another thing I found when using Aida and my G19 keyboard. I set Aida to show me the resolution and refresh rate on the G19 screen. When the monitor tries to sleep and starts acting weird, the resolution is changed from the default setting to some other random setting, usually 3455x900 and a refresh rate of 75Hz. That resolution is not always the same, but it is a change that might be worth noting.
 
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