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by dathinab 659 days ago
> The only real thing holding onto DisplayPort is eARC and some minor CEC features for AV receiver/soundbar use. Introducing some dedicated audio port would not only be a huge upgrade (some successor to toslink with more bandwidth and remote control support), but would also remove the pressure to use HDMI.

USB-C

I mean think about it

USB-C/DP alternative mode is good enough as upstream for most use cases (including consoles)and has some additional future feature potential, and still has some USB bandwidth left usable for various things including CEC

for eARC-like use-cases (i.e. sometimes audio+video upstream, sometimes audio downstream) you have a few choices (one needs to be standardized):

- always create a DP alt mod channel upstream, use audio over USB for downstream, technically that already can work today but getting audio latency synchronization and similar right might require some more work

- switch the DP alt mode connection direction or have some audio only alt mode, which either requires a extension of the DP alt mode standard, or a reconnect. But I think the first solution is just fine

as an added benefit stuff like sharing input devices became easier and things like Roku TV sticks can safe on some royalties ... which is part of where the issue is there is a huge overlap between big TV makers and HDMI share holders, I mean have you ever wondered why most TVs don't even have a single DP port even through that would be trivial to add?

which is also why I think there is no eARC like standard for USB-C/DP alt mode, it only matters for TVs and TVs don't have DP support

honestly I believe the only reasons why TVs haven't (very slowly) started to migrate to USB-C/DP alt mode is that most of their producers make money with HDMI

and lastly there is some trend to PCIe everything in both consumer and server hardware. In the consumer segment it had been somewhat limited to the "luxury" segment, i.e. Thunderbolt. But with USB4 it slowly ends up in more and more places. So who knows PCIe based video might just replace both of them (and go over USB-C)

1 comments

> and lastly there is some trend to PCIe everything in both consumer and server hardware. In the consumer segment it had been somewhat limited to the "luxury" segment, i.e. Thunderbolt. But with USB4 it slowly ends up in more and more places. So who knows PCIe based video might just replace both of them (and go over USB-C)

Thunderbolt/USB4 is not PCIe. It's a transport layer that can run multiple applications at once, sharing bandwidth based on use. This is opposed to USB-C Alternate Mode, where pins are physically reassigned to a specific application, which uses the pins regardless of whether it needs the bandwidth.

PCIe is then one of the supported applications running on top of the transport.

I know, but this isn't relevant for the argument, if anything it's in favor of some future protocol replacing HDMI/DP/USB-C+DP alt while using the USB-C connector.
I was just pointing out specifically that there is no such thing as PCIe-based video - nor is there any need for that.

Support for USB4/Thunderbolt DP will proliferate, but there is still benefit to a DP altmode as it's free to implement (the host controller just wires its existing DP input lanes directly to the USB-C connector) and allows for super cheap passive adapters.

If USB-C ends up becoming the standard video connector as well, it will most likely be DP altmode as you then only need a cheap USB-C controller to negotiate the mode.

There isn't really any pressure to invent a new protocol. https://xkcd.com/927/