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Scholar mrbietola
Scholar
298 Views
Registered: ‎05-31-2012

ZynqMP DisplayPort Linux driver no support for YCBCR?

Hi, i'm trying to enable graphics for a Zynq MPsoc.

I have live video in YcbCr and live output in YCbCr. Graphics will be RGB. I enabled the converter inside DP.

In linux my application run Xorg, it modifies the output bringing back RGB output. I can't see any graphics.

I read in the driver page

https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18842105/ZynqMP+DisplayPort+Linux+driver

that  12 bit YUV formats are not supported.

What doues this mean? that i cannot use output as YCbCr from DP when using linux?

That would make sense considering that i don' see the graphics.

Since i need an SDI video chain, i should then configure the DP to work in RGB and do the 444:422  RGB YCbCr outside right?

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5 Replies
Moderator
Moderator
276 Views
Registered: ‎11-09-2015

Re: ZynqMP DisplayPort Linux driver no support for YCBCR?

Hi @mrbietola 

The page only mentions that 12-bits YUV is not supported. But this still means that 6/8/and 10-bits YCbCr are supported.

Do you get any output with RGB?

Once again, you are in an unsupported usecase (using the live output without the PHY) so I am not sure what will be the behaviour of the driver


Florent
Product Application Engineer - Xilinx Technical Support EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**
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Scholar mrbietola
Scholar
175 Views
Registered: ‎05-31-2012

Re: ZynqMP DisplayPort Linux driver no support for YCBCR?

Hi @florentw ,

i make the graphics work with RGB, the problem was the xorg.conf config because the timing it uses must be the same of SDI (in my case for 1280x720@50Hz), not the timing for display port (DMT timing if i'm not wrong).

Anyway displayport live output is always 12 bits per component RGB or YCbCr(from the manual), if i configure everything rgb i have no problem (so live input, graphics and live output).

If i set llive video to YCbCr, when linux starts it reconfigures the output and i see wrong colors. So i would like to know if this is expected and if there is a gentle way to tell linux (or Xorg) that i use YCbCr. As an alternative, i'm thinking about configure the DP output after linux load overwriting the linux behaviour

Moderator
Moderator
83 Views
Registered: ‎11-09-2015

Re: ZynqMP DisplayPort Linux driver no support for YCBCR?

HI @mrbietola 

Sorry about the delay on this. Were you able to make any progress and find how to set the color space in linux?


Florent
Product Application Engineer - Xilinx Technical Support EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**
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Scholar mrbietola
Scholar
57 Views
Registered: ‎05-31-2012

Re: ZynqMP DisplayPort Linux driver no support for YCBCR?

i haven't tried yet, i was looking at thr device driver bindings, the old specifies the color space, maybe i can specify it also with the new.

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Moderator
Moderator
48 Views
Registered: ‎11-09-2015

Re: ZynqMP DisplayPort Linux driver no support for YCBCR?

HI @mrbietola 

You will be able to change what clolor space you say you support, so setting YUV422 only might be a solution.

But I guess there should be another solution from linux side to set the default. But I do not have enough knowledge on linux for that...

@sandeepg 

Would you know how to set the default color space used by xorg for the displayport controller?

Thanks


Florent
Product Application Engineer - Xilinx Technical Support EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**
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