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Explorer
Explorer
3,359 Views
Registered: ‎08-31-2016

HDMI Pass-through design: hdmi output blinking black screen

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Hi,

 

I'm observing blinking black screen while checking the HDMI Output at UHD@60fps. I'm testing the ZCU102 Pass through example design ( https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18842083/HDMI+FrameBuffer+Example+Design+2018.1 ). 

 

However with UHD@30fps I am not seeing this blinking problem. My monitor and cable both supports UHD@60fps.

 

What could be reason for this problem in the example design from xilinx?

 

Vinay

 

Vinay Shenoy
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Explorer
Explorer
2,759 Views
Registered: ‎08-31-2016

Hi @xud,
In the mean time, I was able to purchase and check with a new UHD@60fps monitor ( LG 24UD58). I am not seeing any HDMI blinking/black screen issues.
I think the previous monitor doesn't work well with UHD@60fps.

Thanks for your support @xud @watari

Vinay

Vinay Shenoy

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Teacher
Teacher
3,356 Views
Registered: ‎06-16-2013

Hi @vinay_shenoy

 

I'm not sure. But I think that this information is helpful for you.

 

https://www.xilinx.com/support/answers/70515.html

 

Best regards,

 

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Scholar
Scholar
3,339 Views
Registered: ‎08-07-2014

@vinay_shenoy,

 

Are you connecting the HPD (hot plug detect) pin properly?

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Explorer
Explorer
3,329 Views
Registered: ‎08-31-2016
Hi @watari,

I don't think blinking black screen could because of ES Retimer IC.

We have successfully checked output at 4K@60fps for Xilinx HDMI pass through example design ie., SDK based xilinx example design without frame buffers and this design works fine in ZCU102.

Vinay Shenoy
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Explorer
Explorer
3,329 Views
Registered: ‎08-31-2016
Hi @dpaul24,

Yes, HPD assertions are proper.
Vinay Shenoy
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Xilinx Employee
Xilinx Employee
3,289 Views
Registered: ‎08-02-2007

@vinay_shenoy

 

I need to check if I can reproduce the problem. Can I check if you see issues on ZCU102 production board or ES board?

 

Can you type "d", and then print out the event logs, which may give me more hint?

 

What you test UHD@60fps, do you refer to 3840x2160 or 4096x2160? If your monitor only supports 3840x2160p60, but HDMI design outputs 4096x2160p60, it's likely to have blink issues. I have seen this before.

 

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Moderator
Moderator
3,271 Views
Registered: ‎10-04-2017

Hi @vinay_shenoy,

 

To add to the list of open questions:

 

Have you changed the reference clock constraints of the design? Are they being set to the system default of 297MHz or have you changed this?

 

 

-Sam

 

Don't forget to reply, kudo, and accept as solution.

Xilinx Video Design Hub
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Explorer
Explorer
3,252 Views
Registered: ‎08-31-2016

Hi @xud

 

I observed this issue with ZCU102 production board.

 

By UHD @60 I mean 3840x2160 @60fps. I'm giving input at this resolution and my monitor too supports this.

 

Are you able to reproduce this problem at your side?

 

Regards,

Vinay

 

Vinay Shenoy
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Explorer
Explorer
3,251 Views
Registered: ‎08-31-2016

@samk

 

I have not changed the default constraints. 

 

Vinay Shenoy
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Teacher
Teacher
3,201 Views
Registered: ‎06-16-2013

Hi @vinay_shenoy

 

There are different TMDS clock calculation formula between UHD@30Hz and UHD@60Hz.

 

Under UHD@30Hz TMDS Dtata = TMDS Clock /10 (Color Depth=8bit)

Over  UHD@30Hz TMDS Dtata = TMDS Clock /40 (Color Depth=8bit)

 

I guess, I suspect the following, if your monitor and calbe both support UDH@60fps.

Would you make sure them ?

 

- Insufficient eye diagram (Especially TMDS Data lane)

- Large diffrebce between ideal TMDS clock frecueny and accutual TMDS clock frequency

  => Some monitor might not be able to output video signals.

- Clock jitter

 

Best regards,

 

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Xilinx Employee
Xilinx Employee
3,002 Views
Registered: ‎08-02-2007

@vinay_shenoy

 

As per discussed, I have used your boot image and done following test :

  • QD780D (4kp60 RGB without Audio) – ZCU102-QD780D  : I don’t see flicker images. Also there is no error in received image
  • QD780D (4kp60 RGB with Audio Dolby TrueHD 192khz) –> ZCU102 -> Dell UP 3216Q, I don’t see the flicker, and audio can be detected properly

It's confirmed that your LG 40UF670T is only compatible with HDMI 1.4. 

 

As I mentioned previously, it's known that you will see flicker image when you are trying to send a stream has higher bandwidth than the max bandwidth of your Sink. 

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Explorer
Explorer
2,957 Views
Registered: ‎08-31-2016

Hi @xud

 

Just for you information, the blinking of image/video may not been seen if you're checking for few seconds to a minute.

Hence, I'd request you to check the design by keeping the image/video running at UHD @60fps for about 2 - 5 minutes.

 

Please let me know your observations

 

Regards,

Vinay Shenoy

Vinay Shenoy
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Xilinx Employee
Xilinx Employee
2,951 Views
Registered: ‎08-02-2007

@vinay_shenoy

 

There is a known issue that DP159 ES chip on the board may cause video blinking. It can occur on ZCU102 production board, or ES board. The only way to check the date code of DP159 chip.

 

Can you send the picture of DP159, or contact TI, and ensure the chip on board isn't ES chip?

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Xilinx Employee
Xilinx Employee
2,849 Views
Registered: ‎08-02-2007

Just an update on this issue :

Vinay doesn't see this issue on ZCU102 HDMI example design with standalone driver, he only sees this issue in ZCU102 base TRD and ZCU102 Frame Buffer example design.

 

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Explorer
Explorer
2,760 Views
Registered: ‎08-31-2016

Hi @xud,
In the mean time, I was able to purchase and check with a new UHD@60fps monitor ( LG 24UD58). I am not seeing any HDMI blinking/black screen issues.
I think the previous monitor doesn't work well with UHD@60fps.

Thanks for your support @xud @watari

Vinay

Vinay Shenoy

View solution in original post

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Explorer
Explorer
2,625 Views
Registered: ‎08-31-2016

Hi @xud

In couple of my boards, I'm not able to get the HDMI RX video properly. I have ensured that the hardware settings are same as in case of working board.

What I see is that the hdmi_hb helper core (for RX path) output doesn't toggle. This status will toggle whenever there is RX data activity at VPHY Controller. Is it possible to solve this issue by tuning any VPHY or RX Subsystem parameters?

Please give me your inputs

Best Regards,

Vinay Shenoy

Vinay Shenoy
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