Display Port Cable Issues

Craz

Craz

New member
caveman-jim said:
I had better luck with 13.1 and 13.2 and eyefinity after I swapped out my display port dongles, apparently 12.11 wasn't as sensitive? somthing changed anyway... very odd. looking at buying new cables now. :nuts:
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Check your displayport cables when I was troubleshooting the x79 system hang awhile back I found my cables were not compliant with VESA standards. I used to get displayport link failure messages all the time. Here is some info from my post i made on another website:

If you read the VESA Displayport standard it states.
Here on page 147

3.2.2 DP_PWR Wire

A standard DisplayPort cable must have no wire for the DP_PWR pin.
Only captive cables supplied with cable powered Branch Devices or cables permanently attached to Sink
Devices are permitted to have the wire for DP_PWR. These captive/attached cables must have a standard
DisplayPort plug connector (as specified in Section 4.2.1) on one end only. The other end must either be
permanently attached or have a custom connector.

If you look at the pin out for a DP cable.

Pin out

External connector (source-side) on PCB
Pin 1 ML_Lane 0 (p) Lane 0 (positive)
Pin 2 GND Ground
Pin 3 ML_Lane 0 (n) Lane 0 (negative)
Pin 4 ML_Lane 1 (p) Lane 1 (positive)
Pin 5 GND Ground
Pin 6 ML_Lane 1 (n) Lane 1 (negative)
Pin 7 ML_Lane 2 (p) Lane 2 (positive)
Pin 8 GND Ground
Pin 9 ML_Lane 2 (n) Lane 2 (negative)
Pin 10 ML_Lane 3 (p) Lane 3 (positive)
Pin 11 GND Ground
Pin 12 ML_Lane 3 (n) Lane 3 (negative)
Pin 13 CONFIG1 connected to Ground1)
Pin 14 CONFIG2 connected to Ground1)
Pin 15 AUX CH (p) Auxiliary Channel (positive)
Pin 16 GND Ground
Pin 17 AUX CH (n) Auxiliary Channel (negative)
Pin 18 Hot Plug Hot Plug Detect
Pin 19 Return Return for Power
Pin 20 DP_PWR Power for connector (3.3 V 500 mA)

On a standard Displayport cable being used to hook up monitor to video card.
Pin 20 DP_PWR Power should not be connected. It is back feeding 3.3v back into the video card causing all kinds of issues. A lot of company are pushing out products that are not following the correct VESA Displayport Standards.

I tested this by removing my video card and connecting Displayport cables. These are Monster Digital Life cable.

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Measured here from negative lead on meter to screw on back of card.

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And Reading 3.3v on video card. (MSI 7970 reference card)

ecc694abimg0241.jpg


The cables I found to be compliant are Belkin Displayport Male to Displayport Male. I did away with using the Mini-DP to DP cables and am using the Mini-DP to DP female dongle that was included with my MSI reference 7970's.

Here is a link to the compliant cables.
http://www.amazon.com/gp/aw/cr/B0017U61M8/ref=aw_d_cr_electronics

I tested monster displayport cables and some cheap startech cables. Both were non compliant pin 20 was connected back feeding 3.3v. Belkin is the brand of cable I am using now. I havent had a displaylink failure since switching to the belkin compliant cables.

Anyways, I hope someone finds this info usefull..
 
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Craz said:
Stuff...
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Mayyyyte, you're an absolute legend...

I've been plagued, almost gone insane, with this issue for the last year with the dreaded 'not optimised resolution' error on my Samsung S27A950s.. I have 3 of these monitors, so in any one 5 hour stretch, I get 4-5 error messages which drives me bonkers..

I've replaced the cables 4 times, gone back to Samsung as I believed it was a hardware fault/design flaw, all of which has resulted in nothing but frustration, expensive troubleshooting and time wasted.

I just cannot believe that 99% of all displayport cables aren't to spec, as even the officially supplied samsung cables do the same thing. You'd think that someone would have come across the issue before now as displayport has been out for some time now, 2? years, and mostly all available cables are still wrong..

I've just placed an order with with amazon for those belkin cables (which you can't even buy in australia), so fingers crossed that it's all resolved.

If you're ever in Australia, I'd love to buy you a beer as thanks.. Many, many thanks.
 
Tried this on a 6670 and a 6870, both showed ~2.9v on pin 20. Used two different cables, one DP-DP and one mDP-DP to my Dell P2210h monitor.

I'll check into this more.
 
caveman-jim said:
Tried this on a 6670 and a 6870, both showed ~2.9v on pin 20. Used two different cables, one DP-DP and one mDP-DP to my Dell P2210h monitor.

I'll check into this more.
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so is this just for Eyefinity or any time you get a lot of displayport link failure messages

I get displayport link failure messages once to twice a week with a DisplayPort to DVI Dual Link Active Adapter and have to reboot
http://www.startech.com/AV/Displayp...pter-Converter-DP-to-DVI-D-2560x1600~DP2DVID2
I can't use the built in DVI-DL at 2560x1600 for grain noise in some colors on both of my 7970 directcu ii

the adapter fixes the grain noise but the displayport link failures are a pain, I got two of the adapters and both do it
 
caveman-jim said:
I only see the link failures in Eyefinity groups.
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I can confirm it. Since I bought new monitors last week (two of them with DisplayPort) I'm suffering it. Even changing Windows desktop resolution from 5760x1080 to 1920x1080 makes all monitors start flashing, disconnecting and the Windows sound of "new hardware connected" plays every few seconds.

Starting a game for the first time is a nightmare. If the game does not detect and configure itself for Eyefinity resolutions and tries to launch in 1920x1080 or something like that, it may take a while to get to the game options and configure it.

It sometimes end in a full system crash. Horrible.
 
caveman-jim said:
It's the cables.... more on this soon.
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It will be interesting to see what you figure out. When I was having the system freezes Raja from asus, if I remember correct suggested I check the cables. I tested the cables and moved on and didn't even think about the link failures and not getting them until you all started mentioning having issues. I then realized I didn't have anymore since changing the cables back then.
 
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Craz said:
It will be interesting to see what you figure out. When I was having the system freezes Raja from asus, if I remember correct suggested I check the cables. I tested the cables and moved on and didn't even think about the link failures and not getting them until you all started mentioning having issues. I then realized I didn't have anymore since changing the cables back then.
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Thanks for the info, article coming soon. :)*
 
Having bought 3 belkin cables from amazon, I can confirm that it hasn't fixed the issue..

It's the same as it ever was...

$110 down the drain.. doh! lol
 
caveman-jim said:
Thanks for the info, article coming soon. :)*
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so should I try to figure out which is pin 20 and disconnect it if it is connected on these displayport to dvi adapters
to stop these link failures and displayport lower setting applied

and thanks for the coming article
img0189tm.jpg
 
bill dennison said:
so should I try to figure out which is pin 20 and disconnect it if it is connected on these displayport to dvi adapters
to stop these link failures and displayport lower setting applied

and thanks for the coming article
img0189tm.jpg
Click to expand...

That's an interesting thought. Do you have a multi-meter? If you do, I'd like you to test the following, if it's not too much trouble.

Remove GPU from computer. Plug in DVI cable to monitor and to your powered, active DP-DVI adapter. Plug DP adapter into DP output on card. Test the DP pins (as you saw on the other post) for presence of voltage (should read 3.3v but might be around 3v).

If you find a point where you get voltage, use your third arm :manches2: to snap a quick pic and send it to me, please. Also that means yes, you need to find the pin 20 inside the adapter and disable it because that's DP_PWR signal feeding back into the card.
 
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caveman-jim said:
That's an interesting thought. Do you have a multi-meter? If you do, I'd like you to test the following, if it's not too much trouble.

Remove GPU from computer. Plug in DVI cable to monitor and to your powered, active DP-DVI adapter. Plug DP adapter into DP output on card. Test the DP pins (as you saw on the other post) for presence of voltage (should read 3.3v but might be around 3v).

If you find a point where you get voltage, use your third arm :manches2: to snap a quick pic and send it to me, please. Also that means yes, you need to find the pin 20 inside the adapter and disable it because that's DP_PWR signal feeding back into the card.





No. The feature was removed because it was possible in theory for the downloader to be tricked into downloading something else, that wasn't an official AMD catalyst update which you'd run, i.e. software on your system would change the download and then you'd download and run it thinking it was an update. AMD removed the feature when they discovered the vulnerability but weren't aware of any exploits. I'd say you were fine but you can check out your system using a free online virus scanner to be sure.
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ok
I will try latter
but how about if I read pin 20 from the adapter dp cable to what the inside of adapter case as ground ?
or one of the ground pins
570pxdisplayportconnect.png


will have to plug it into a live usb plug to as that powers it to
and use small pins on my meter
I would think pins 2 and 20 would work

my asus 7970 directcu ii has a back plate that blocks that points on back and I don't want to void waranty
 
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When poking around just make sure what you are reading is not the Hot Plug Detection, it also has 3.3v on it. If you find 3.3v on the card leave the cable plugged in to the video card then disconnect it from the monitor then OHM the cable from pin 20 on the connector to where you are measuring 3v +/-. If you have one lead on the point you are reading 3v and the other on pin 20 you should read around .3 ohms if pin 20 is connected, and making good connection with the meter probe on both ends. You can also use this method to test with no power at all. I didn't put this in my original post but it is something I used to double check my finding because, I was unsure about the circuit board layout on the 7970 and if what I was reading was actually pin 20. With out much published info, it is trial and error each video card/monitor is different. But from what I have read from alot of post, these adapters and cables can cause a lots of grief. Until you eliminate a bad cable or adapter you are pretty much guessing at what can be causing monitor issues. It is no different then a bad DVI cable just a little more complex. Displayport is still relatively new, hell I been waiting for displayport hubs forever!

Also the picture you posted make sure you get the orientation correct! That pic is what you would see looking at a source device (AKA starring at a empty connector on a card or monitor). So your cable if you were to plug that in, looking at pin 20 would be the bottom left pin if you are look at it as if you are plugging the cable into the picture.

Again: Sorry if I am unclear on my post I am terrible at communicating. Tech background and yeah my hand writing is terrible as well!
 
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Craz said:
When poking around just make sure what you are reading is not the Hot Plug Detection, it also has 3.3v on it. If you find 3.3v on the card leave the cable plugged in to the video card then disconnect it from the monitor then OHM the cable from pin 20 on the connector to where you are measuring 3v +/-. If you have one lead on the point you are reading 3v and the other on pin 20 you should read around .3 ohms if pin 20 is connected, and making good connection with the meter probe on both ends. You can also use this method to test with no power at all. I didn't put this in my original post but it is something I used to double check my finding because, I was unsure about the circuit board layout on the 7970 and if what I was reading was actually pin 20. With out much published info, it is trial and error each video card/monitor is different. But from what I have read from alot of post, these adapters and cables can cause a lots of grief. Until you eliminate a bad cable or adapter you are pretty much guessing at what can be causing monitor issues. It is no different then a bad DVI cable just a little more complex. Displayport is still relatively new, hell I been waiting for displayport hubs forever!

Also the picture you posted make sure you get the orientation correct! That pic is what you would see looking at a source device (AKA starring at a empty connector on a card or monitor). So your cable if you were to plug that in, looking at pin 20 would be the bottom left pin if you are look at it as if you are plugging the cable into the picture.

Again: Sorry if I am unclear on my post I am terrible at communicating. Tech background and yeah my hand writing is terrible as well!
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ok thanks
i'm a hvac technician so i'm a little over my haed
my writing is 6 and 8 gauge wire :lol:

no power on pin 20 to ground, I think
but I don't think the dp to dvi active adapter is turning on without being fully hooked up

and my hp lp3065 input button won't switch to a dead cable

I have a extra adapter so I think just cut pin 20 wire and try it
when I get a chance
 
Figured I'd join in on this conversation about displayport and its issue..

I own 3x Samsung S27A950 (120hz & 3D) monitors connected to an Asus 7970 DCUII via 3 full sized displayport cables. Over the course of about 1.5? years, I've been living through a displayport nightmare, in that I'd get constant dropouts with the dreaded 'Not optimal resolution' message.

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Whenever I get the error, I have to switch the monitor off, which resets the screen and gets rid of the error. As you're all well aware, because displayport is classed as a device, when you switch off the monitor, it removes it from the PC. So if i'm playing a game, the game will crash and cause me to severely rage. Because I have 3 monitors, I'll get like 4-5 crashes in any one 5 hr gaming session, so it's been driving me bonkers. The reason why I want to stick to displayport is that I run eyefinity 3D, so that I get games, in eyefinity, in 3D across 3 screens. When it's working, it's phenomenal, like jawdroppingly gorgeous..

Over the course of 1.5 yrs, I've replaced the cables 5? times now. I've got samsung to supply their own cables, which did nothing. I've sent the monitors back to samsung which they did a 'firmware update'. I gave up with samsung as it was going nowhere, even if they were helpful.

Fast forward to last week, when I did some googling and noticed that few other people were having issues with displayport and that it was remedied by disabling DDC in their monitor (my monitor doesn't have any setting to disable it), and further googling showed that AMD External Events Utility is the equilivant of this. I hastily disabled it, and low & behold, the dropouts _almost_ vanished.. I wrote about this on HardOCP, and was pointed to this thread, with the cables confirming to be the issue.

I went ahead and bought the belkin cables from amazon, and re-enabled the Events Utility. Guess what? The dropouts are back. Disabling the Events Utility has stopped the dropouts..

I can't help but feel that the cables aren't the issue. More likely the dodgy AMD drivers as it's been an issue in the past, and perhaps was never actually fixed. In the release notes for 10.1 cats, it has this point..

"DisplayPort™ "Lower Setting Applied" and "Link Failure" messages will no longer appear after driver installation and reboot with DP displays connected to the mini DP port"

It's the exact same error that I get whenever a display fails. However, I'm using full sized DP connectors..
 
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Vladdo said:
Fast forward to last week, when I did some googling and noticed that few other people were having issues with displayport and that it was remedied by disabling DDC in their monitor (my monitor doesn't have any setting to disable it), and further googling showed that AMD External Events Utility is the equilivant of this. I hastily disabled it, and low & behold, the dropouts _almost_ vanished..
Click to expand...

Can't wait to get home and try this, and if it indeed fixes the problem, I'll ask AMD about it. Thank you very much for your post.

EDIT: Tested it, it didn't change anything for me :-(
 
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