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This is upsetting on principle alone. But I'm also upset because I have my PC hooked up to my TV for couch gaming and was hoping to do that on Linux sooner rath

This is upsetting on principle alone. But I'm also upset because I have my PC hooked up to my TV for couch gaming and was hoping to do that on Linux sooner rather than later when HDR works properly. I wasn't aware HDMI 2.1 was another problem... I guess Windows is sticking around for that.

macNchz 3y ago
FWIW I have my Linux desktop hooked up to a 4k/120hz TV via a $30 CableMatters DisplayPort->HDMI dongle that seemingly supports most of the relevant functionality, as far as I can tell. It even works very smoothly over a 50 foot active fiber optic HDMI cable. There is a ton of discussion about these dongles in the issue thread linked in the article.
- Cu3PO42 3y ago
  That's an excellent point. Coincidentally I also have a 15m active fiber optic HDMI cable. If and when this is the last blocker, I'll definitely look at available adapters!
- account42 3y ago
  Can you provide the exact model? Does "most of the relevant functionality" include VRR/FreeSync? Not that it would be a complete solution for me since I'm limited to DP 1.4.
  - soulbadguy 3y ago
    >include VRR/FreeSync? I have been looking for a display port -> hdmi adapter with vrr support for a while.AFAIK, nothing on the market currently supports it, including the cable from cablemod mentioned by OP
boomskats 3y ago
HDMI 2.0 is capable of doing 4k @ 120Hz, but only up to YCbCr 4:2:0 8bit instead of the full YCbCr 4:4:4 10bit (though I'm not sure how close wayland is to 10bit support). It will be fine for gaming, just not for everyday PC use. FWIW I also didn't realise this until just now. I've been running my desktop at 4k@120hz recently for the buttery smooth neovide, but have been noticing that text rendering, especially syntax-highlighted text, looks awful. I'd seen the same oled panel render text way better in WSL/Windows (both using a custom pixel geometry[0] via Mactype, but also without), so I spent more time than I'm willing to admit to wrapping my head around custom pixel layouts and hinting in freetype. But no, turns out it was this all along. If you want to see the effect of 420 vs 444 chroma subsampling on text rendering, this writeup[1] has some great test images and is well worth a read. Also, if you happen to have an LG OLED panel, you can get a little debug window that confirms your signal format and refresh rate, by pressing the green button on the remote 7-8 times. [0]: https://github.com/snowie2000/mactype/issues/720 https://github.com/snowie2000/mactype/issues/720 [1]: https://www.rtings.com/tv/learn/chroma-subsampling https://www.rtings.com/tv/learn/chroma-subsampling
- _kb 3y ago
  Another immensely useful source and pattern generator is also https://www.extron.com/article/testpattern https://www.extron.com/article/testpattern.
- Cu3PO42 3y ago
  I once had a bad cable, which forced a 4k@60 monitor into chroma subsampling. Or rather Windows decided it would rather enable Chroma subsampling than drop resolution or framerate. I immediately noticed there was something wrong. I agree it's terrible for desktop use. I would probably also have blamed freetype if it only happened on Linux, though.
- account42 3y ago
  > It will be fine for gaming I disagree. Gaming can involve lots of (colored) text too. And besides, if you have invested in a 4k@120Hz monitor are you really going to accept chroma subsampling even for non-text content? I hate how the connection just magically switches to chroma subsampling (and/or DSC with newer connection standards) instead of that being something you have to explicitly enable. Well with my montor (and AMD card limited to HDMI 2.0 due the BS in TFA) it at least defaults to 60 Hz but there is no indication what the consequences of setting it to 120 Hz are. You're not even told that your connection has been downgraded by any OS I have tried. Absurd that you have to result to these test patterns.
0xedd 3y ago
There are different cable converters available. That said, if the hardware is user hostile don't use it. What are birthdays for if not throwing out trash and replacing it.
- Cu3PO42 3y ago
  What is the hardware I would be replacing here? My TV? I'm not aware of any options with DP support. My GPU? I only just replaced my 3070 Ti with a 7900 XTX because of the open source drivers and much better Linux support. The converters are an excellent point though. Not sure why I didn't think of them...
  - account42 3y ago
    AFAIK there is no converter that is a complete solution, i.e. can translate all the features including VRR/FreeSync.
- account42 3y ago
  > What are birthdays for if not throwing out trash and replacing it. You are free to send me a couple grant for my birthday to buy a new equivalent TV with display port connectors. Except you can't even do that because such a TV does not exist.

macNchz 3y ago

FWIW I have my Linux desktop hooked up to a 4k/120hz TV via a $30 CableMatters DisplayPort->HDMI dongle that seemingly supports most of the relevant functionality, as far as I can tell. It even works very smoothly over a 50 foot active fiber optic HDMI cable. There is a ton of discussion about these dongles in the issue thread linked in the article.

Cu3PO42 3y ago
That's an excellent point. Coincidentally I also have a 15m active fiber optic HDMI cable. If and when this is the last blocker, I'll definitely look at available adapters!
account42 3y ago
Can you provide the exact model? Does "most of the relevant functionality" include VRR/FreeSync? Not that it would be a complete solution for me since I'm limited to DP 1.4.
- soulbadguy 3y ago
  >include VRR/FreeSync? I have been looking for a display port -> hdmi adapter with vrr support for a while.AFAIK, nothing on the market currently supports it, including the cable from cablemod mentioned by OP

boomskats 3y ago

HDMI 2.0 is capable of doing 4k @ 120Hz, but only up to YCbCr 4:2:0 8bit instead of the full YCbCr 4:4:4 10bit (though I'm not sure how close wayland is to 10bit support). It will be fine for gaming, just not for everyday PC use. FWIW I also didn't realise this until just now. I've been running my desktop at 4k@120hz recently for the buttery smooth neovide, but have been noticing that text rendering, especially syntax-highlighted text, looks awful. I'd seen the same oled panel render text way better in WSL/Windows (both using a custom pixel geometry[0] via Mactype, but also without), so I spent more time than I'm willing to admit to wrapping my head around custom pixel layouts and hinting in freetype. But no, turns out it was this all along. If you want to see the effect of 420 vs 444 chroma subsampling on text rendering, this writeup[1] has some great test images and is well worth a read. Also, if you happen to have an LG OLED panel, you can get a little debug window that confirms your signal format and refresh rate, by pressing the green button on the remote 7-8 times. [0]: https://github.com/snowie2000/mactype/issues/720 https://github.com/snowie2000/mactype/issues/720 [1]: https://www.rtings.com/tv/learn/chroma-subsampling https://www.rtings.com/tv/learn/chroma-subsampling

_kb 3y ago
Another immensely useful source and pattern generator is also https://www.extron.com/article/testpattern https://www.extron.com/article/testpattern.
Cu3PO42 3y ago
I once had a bad cable, which forced a 4k@60 monitor into chroma subsampling. Or rather Windows decided it would rather enable Chroma subsampling than drop resolution or framerate. I immediately noticed there was something wrong. I agree it's terrible for desktop use. I would probably also have blamed freetype if it only happened on Linux, though.
account42 3y ago
> It will be fine for gaming I disagree. Gaming can involve lots of (colored) text too. And besides, if you have invested in a 4k@120Hz monitor are you really going to accept chroma subsampling even for non-text content? I hate how the connection just magically switches to chroma subsampling (and/or DSC with newer connection standards) instead of that being something you have to explicitly enable. Well with my montor (and AMD card limited to HDMI 2.0 due the BS in TFA) it at least defaults to 60 Hz but there is no indication what the consequences of setting it to 120 Hz are. You're not even told that your connection has been downgraded by any OS I have tried. Absurd that you have to result to these test patterns.

0xedd 3y ago

There are different cable converters available. That said, if the hardware is user hostile don't use it. What are birthdays for if not throwing out trash and replacing it.

Cu3PO42 3y ago
What is the hardware I would be replacing here? My TV? I'm not aware of any options with DP support. My GPU? I only just replaced my 3070 Ti with a 7900 XTX because of the open source drivers and much better Linux support. The converters are an excellent point though. Not sure why I didn't think of them...
- account42 3y ago
  AFAIK there is no converter that is a complete solution, i.e. can translate all the features including VRR/FreeSync.
account42 3y ago
> What are birthdays for if not throwing out trash and replacing it. You are free to send me a couple grant for my birthday to buy a new equivalent TV with display port connectors. Except you can't even do that because such a TV does not exist.