this post was submitted on 29 Feb 2024
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[–] altima_neo 23 points 8 months ago (5 children)
[–] [email protected] 87 points 8 months ago (1 children)

USB-C display output uses the Display Port protocol

[–] [email protected] 24 points 8 months ago (2 children)

Can it use others, and is there a benefit? USB C makes a lot of sense; lower material usage, small, carries data, power and connects to almost everything now.

[–] [email protected] 52 points 8 months ago (6 children)

I believe USB-C is the only connector supported for carrying DisplayPort signals other than DisplayPort itself.

The biggest issue with USB-C for display in my opinion is that cable specs vary so much. A cable with a type c end could carry anywhere from 60-10000MB/s and deliver anywhere from 5-240W. What's worse is that most aren't labeled, so even if you know what spec you need you're going to have a hell of a time finding it in a pile of identical black cables.

Not that I dislike USB-C. It's a great connector, but the branding of USB has always been a mess.

[–] [email protected] 17 points 8 months ago* (last edited 8 months ago) (2 children)

would be neat to somehow have a standard color coding. kinda how USB 3 is (usually) blue, maybe there could be thin bands of color on the connector?

better yet, maybe some raised bumps so visually impaired people could feel what type it was. for example one dot is USB 2, two could be USB 3, etc

[–] [email protected] 20 points 8 months ago (1 children)

Have you looked at the naming of the usb standards? No you havn't otherwise you wouldn't make this sensible suggestion.

[–] [email protected] 6 points 8 months ago (1 children)

the shenenigans with USB 3 naming you mean? you're right, this would be too logical for USB lol

[–] [email protected] 2 points 8 months ago (1 children)

Don't worry, they made it worse with usb 4.

[–] [email protected] 1 points 8 months ago (1 children)
[–] [email protected] 3 points 8 months ago (1 children)

USB 3.2 2x2 with 20 Gbps is the same as USB 4 Gen 2×2 with 20 Gbps

USB 4 Gen3x2 has 40 Gbps and was then renamed to USB 4 1.0

[–] [email protected] 4 points 8 months ago

jesus what the fuck

[–] [email protected] 3 points 8 months ago

Please think of the shareholders... :(

[–] [email protected] 4 points 8 months ago (1 children)

I think that the biggest issue with dp over usbc is that people are going to try to use the same cable for 4k and large data transfers at the same time, and will then whine about weird behaviour.

[–] [email protected] 1 points 8 months ago

4K works for mine (it's 3.2).

[–] [email protected] 3 points 8 months ago

Yep, very true. I didn't understand this until I couldn't connect my Mac to my screen via the USB C given with the computer, I had to buy another (and order it in specifically). Pick up a cable, and I have no idea which version it is.

[–] [email protected] 1 points 8 months ago

Yeah I have multiple USB cables, some at 30w, and some at 140w. Get them mixed up all the time! More companies need to at least brand the wattage on the connectors.

[–] [email protected] 1 points 8 months ago

Dont forget the limited length. I cant remember exactly but usb c delivering power has a max length of arpund 4 metres

[–] [email protected] 0 points 8 months ago

This is the big issue I have with with "USB C". USB c is just the connector which can be used for so many things. What actual is supported depends on things you can't see, like the cable construction or what the device supports.

[–] [email protected] 6 points 8 months ago (1 children)

There's some really high bandwidth stuff that USB-C isn't rated for. You have to really press the limits, though. Something like 4k + 240Hz + HDR.

[–] [email protected] 1 points 8 months ago (2 children)

That doesn't even seem so unreasonable. Is that the limit though? My cable puts a gigabyte a second down it so I wouldn't imagine that would hit the limit.

[–] [email protected] 2 points 8 months ago (2 children)

It is trivial arithmetic: 4.52403840*2160 ≈ 9 GB/ s. Not even close. Even worse, that cable will struggle to get ordinary 60hz 4k delivered.

[–] [email protected] 3 points 8 months ago* (last edited 8 months ago)

4.5 × 240 × 3840 × 2160 ≈ 9 GB/s

It seems markdown formatting ruined your numbers because of the asterisks. Whatever is written between two of those turns italic, so they're not ideal for multiplication symbols here on Lemmy (or any other place that implements markdown formatting).

[–] [email protected] 1 points 8 months ago (1 children)

I think the maths got a bit funky there. I don't think a cable capable of such speeds would struggled to do 60Hz at 4K, it surely doesn't need close to a gigabyte a second?

[–] [email protected] 2 points 8 months ago

It surely does. Check pirates post for clean math formatting

[–] [email protected] 2 points 8 months ago

USB-C with Thunderbolt currently had a limit of 40Gbit/sec. Wikipedia has a table of what DisplayPort can do at that bandwidth:

https://en.wikipedia.org/wiki/DisplayPort

See the section "Resolution and refresh frequency limits". The table there shows it'd be able to do 4k/144hz/10bpp just fine, but can't keep above 60hz for 8k.

Its an uncompressed video signal, and that takes a lot of bandwidth. Though there is a simple lossless compression mode.

[–] [email protected] 20 points 8 months ago (1 children)

USB C is just a connector, you might be referring to Displayport over USB C which is basically just the same standard with a different connector at the end. That or Thunderbolt I guess

[–] [email protected] 4 points 8 months ago

I thought thunderbolt was DP passthrough as well

[–] [email protected] 13 points 8 months ago

USB C seems like a good idea but in reality all it really did was take my 5 different, not interchangeable, but visually distinct, cables, and make them all look identical and require labeling

[–] [email protected] 8 points 8 months ago (1 children)

I love having mysterious cables that may or may not do things I expect them to when plugged into ports that may or may not support the features I think they do.

[–] [email protected] 4 points 8 months ago

If the implementation is so broad that I have to break out my label maker, can we even really call it a "standard"

[–] [email protected] -1 points 8 months ago

you mean thunderbolt?