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January 9th, 2017 12:00

U2417H, DP 1.2 daisy chain mirrors, but does not extend.

I have 2 new dell U2417H which I am trying to connect to my machine via daisy chained displayport. The computer I have it connected to is an HP 400 G3 SFF.  I have confirmed that this computer supports MST via displayport. The current configuration of the connections are as follows:

CPU DP > First Monitor mDP input > First Monitor DP output > Second Monitor mDP input

Both monitors currently have displayport 1.2 enabled. I have done factory resets to both just to be sure. 

Even though the display is mirrored on both monitors, windows does not detect more than one monitor attached.  I am running a fresh install of windows 10 64 bit (I have also tried it on an identical machine fresh out of the box with the same result). I have updated the video drivers to the latest release. It is an onboard Intel HD 530 which supports multistream via displayport. 

Is there any issues with using mDP ports instead of full sized form factor displayports?  Currently The monitors only came with mDP to DP cables and the new cables are on the way, but are a couple of days away. From what I can tell, using mDP shouldn't be an issue because there is no difference other than they are different form factors.

2 Posts

June 7th, 2017 16:00

I had this exact same issue with Dell U2717D monitors.  The monitors were mirrored and showed up in the display manager as one single monitor.  I played with enabling/disabling DP 1.2 on the second monitor to no effect.  Finally I found out that there was another setting in monitor configuration that was simply called "MST".  Evidently this is called "Multi-Stream Transport".  Once I ENABLED MST (in addition to DP 1.2) on the first monitor, the displays un-mirrored themselves and Windows treated them as separate monitors.  Enabling DP 1.2 and MST on the second monitor allowed me to daisy-chain a third monitor.  They are all recognized as 3 separate monitors and can have independent resolution settings.  At least for me, MST was the key.  The MST setting on the U2717D is under DISPLAY -> MST.  For me, at least, this fixed the issue of the displays mirroring while daisy-chained.

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January 9th, 2017 13:00

The second in the chain should be set to MST/DP 1.2 Off. I would also swap them (current primary U2417H change to secondary U2417H) to see if the issue is the same. No, primary U2417H on mDP should work.

3 Posts

January 10th, 2017 06:00

Just switched the secondary to the primary with the same configuration, but it has the same result.

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January 10th, 2017 09:00

Not sure what else you can do but test them on another system with a dedicated video card that has DP or mDP and also testing with a DP to DP cable on that HP. Where did you find HP documentation that stated its onboard DP out port supports DP 1.2 daisychaining? That is not mentioned here or here ?

3 Posts

January 10th, 2017 11:00

Tested with DP to DP, same result. It does mention it on the first PDF you linked. On page 22 it is listed under the 400 G3 SFF (small form factor), which is the model I have:  

1 VGA

1 DisplayPort

with multi-stream

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January 11th, 2017 08:00

I do not think that  the monitors are at fault here. Then the only other option is to test them on another computer. Preferably a computer with an added video card that has DP out or mDP out. Also contact HP support and ask if they successfully tested that system in a two monitor DP 1.2 daisychain.

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June 8th, 2017 09:00

MST (Multi-Stream Transport) and DP 1.2 are the same thing.

Which is why I stated above, "The second in the chain should be set to MST/DP 1.2 Off.". As I showed in the picture, the U2417H manual calls them both out, "DP1.2 with MST option". As does your U2717D manual =

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January 19th, 2018 08:00

I'm going to try this same set-up, but with a laptop that has Radeon 540 graphics. The laptop has one USB type C and one HDMI - do you recommend using the type C port or the HDMI? I need to buy a new cable to connect to the mini display port on the first monitor. Thank you!

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January 20th, 2018 08:00

You cannot start with computer HDMI out to daisychain U2417H. It will have to be the laptop USB Type-C out port.

Computer USB Type-C out --> USB Type-C to DP cable --> #1 U2417H DP in (MST On)
#1 U2417H DP out --> U2417H DP to mDP cable --> #2 U2417H mDP in (MST Off)

2 Posts

February 6th, 2018 12:00

I tried the same, but didn't work. I am using it with Macbook Pro. Is there a solution for Macbook pro?

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February 6th, 2018 13:00

 

Unknown by Dell. As you can see in the image below taken directly from the monitor page, the Apple proprietary hardware, operating system (including Windows bootcamp), cabling, and drivers were not tested/validated by Dell.

U2417H.JPG

Since we at Dell are not trained in the usage of the Apple hardware and operating system, you should ask the Apple users on the Apple Forum for troubleshooting and cabling opinions.

February 23rd, 2018 08:00

You will find DP chaining is unsupported by Apple, used to work in older versions of OS X, but like everything with Apple they think they know best ;-)

February 23rd, 2018 08:00

Hi Guys

I am also having problems with the buggy DP and a Precision 4600m. I have a pair of U2414H, in fact I have 3, but I am only using 2, which have always been a little temperamental, but DP chaining worked ok with my 4600m, Windows 7 x64 and the ATI M5950. They are the older A01 rev, I bought them new and didn't know they had problems, I read else where Dell were RMA'ing them to upgrade the firmware which is supposed to fix a lot of the DP issues, they are now out of warranty and were when I found out... great :-/

Yesterday I decided to test KDE neon from a live USB stick but found that DP chaining wasn't working and plugged in an HDMI cable to test, which worked fine. When I went back to Windows and plugged my DP cable back in, both displays have decided to mirror, with the second monitor not showing up in device manager/screen resolution, nor the ATI catalyst control center. Both monitors work as expected when plugged in direct via DP. Display Port v1.2 is enabled on the first monitor in the chain, although it was enabled on both when working perfectly.

I have tried:

Different display port cables

Different monitors, I have a few U2415's.

I have uninstalled and reinstalled the Video drivers, trying both Dell and the more recent AMD versions.

Can anyone clarify, if I remove the ATI card, does the 4600m drop back to using the Intel HD graphics?

Kind regards

Kevin

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