Intel Iris Plus Graphics DP 1.4 can't output 4K@60Hz on ICL platform, need advanced troubleshooting

[pumachen]

Dear Intel Support Team,
I have a Surface Pro 7 with an Intel Iris (R) Plus Graphics card (GPU driver version: v26.20.100.7641). From everything I understand, 4K@60Hz should be capable of outputing DP 1.4 with this computer and manufacturers like Lenovo, HP and Dell are putting infos about USB-C or TBT3 that can output DP 1.4.

I'm going DP out via a USB-C Docking Station. All my cables are 4K high speed rated for 4K@60Hz. We did test it on MacBook Air 13" and AMD laptop with ryzen 3rd and 4th gen and it was perfectly working under MacOS and Windows!

So where the problem is? I've included my screenshots showing the issue, also the DxDiag and msinfo. Could you please help me get this working??? I can provide any additional information if you needed.

Thank you so much for your time!

[n_scott_pearson]

First of all, you only need DisplayPort 1.2 support in order to achieve 4K@60Hz, so this isn't a DisplayPort 1.2 vs. DisplayPort 1.4 issue.

Secondly, when you have a problem like this, the first thing that you should do is eliminate the dock from the equation. Connect the monitor directly to the USB-C interface. If it works then, you will know that the dock is responsible for the limitation and not the graphics engine.

Your response should (also) include Information about the dock being used.

...S

[Billy0101]

Hi, Scott

The Dock integrated USB3.0 data which means it will be 2 Lane DP, so to achieve 4K@60Hz need HBR3 capability. If ICL did support DP1.4 capability? The same Dock is capable to light 4K@60Hz with AMD Radeon™ VEGA8 which supports DP1.4 output. On the other hand, we also verify that ICL is capable to have Dual 4K@60Hz in 4 Lane DP application and it proves that ICL perform in DP1.4 output. However, how come it's not able to achieve single 4K@60Hz in 2 Lane DP application? Kindly advise.

Billy

[n_scott_pearson]

Again, I can only suggest you verify proper operation with the monitor directly connected to the USB-C port. If that doesn't work, you will need to see what ICL has done. Are you running the latest-available BIOS for this ICL board? If it works, then you will need to see what was done in the dock.

That's all I have, let us know once you have tested without the dock. At that point Intel Customer Support may have to investigate what is going on...

...S

[Billy0101]

Thanks Scott,

Yes, I've updated to latest Driver and FW released from Intel and USB-C cable directly to USB-C monitor or with USB-C to DP monitor can achieve 4K@60Hz with no problem. However, that's not the main issue we are facing. From ICL platform to Monitor directly there is USB3 signal which means USB-C port SSTX1/SSRX1/SSTX2/SSRX2 is running DisplayPort data that HBR2 is capable to perform 4K@60Hz. Therefore, please help to clarify what capability ICL can support? HBR2 or HBR3? If ICL does support HBR3, is there any limitation that we need to pay attention to?

Billy

[n_scott_pearson]

Here is a snippet from the datasheet:

...S

[Dabsihi]

> I'm going DP out via a USB-C Docking Station. 

I think that's the problem. Your Dock may only support DP 1.1 or lower. You should try a USB-C to DP1.4 cable, without any *Docking* things.

[Billy0101]

No, my Dock does support DP1.4 & DSC. I am able to work with 4K@60Hz on AMD platform but not only on ICL platform.........that's the reason I come here to get support.

[n_scott_pearson]

You need to be talking to Microsoft. There are things that they could have done in their USB-C port design which could preclude this from working. Sorry I don't have a better answer, but everything else says it should work.

...S