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HDMI Forum rejects AMD's HDMI 2.1 open-source driver

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Re: HDMI Forum rejects AMD's HDMI 2.1 open-source driver

#71

Post by account42 »

shmerl wrote: post #14
kelnos wrote: post #11

Earlier quoted context omitted.

> Does it though? Does it really? Of course not. It's just protectionism and rent-seeking. > I don't understand this move from HDMI Forum. They're handing a win to DisplayPort. I don't think so, at least at this point. Most people don't have hardware that requires HDMI 2.1 in order to get full use out of them, and of those who do, not all of them use Linux and/or care about open source drivers. Sure, that situation m…

May be it can change if USB 4 will sneak in and supplant HDMI in those devices, since it can route both HDMI and DP.

Is HDMI over USB even a thing that any real devices support? But yeah, demand for mobile phone support might force TV manufacturers to adopt DP over USB.

Re: HDMI Forum rejects AMD's HDMI 2.1 open-source driver

#72

Post by globular-toast »

eqvinox wrote: post #43
shiroiushi wrote: post #10

Earlier quoted context omitted.

>They're handing a win to DisplayPort. Is this useful, if all the relevant devices only have HDMI ports and not DP?

FYI: USB Type-C ports are DP ports on most modern laptops. You just need the correct cable (or a display with Type-C connector.) I have one of these https://www.club-3d.com/en/quick-view/2470/ (actually works both directions, e.g. if you have a portable display with only Type-C connectors like this https://www.hp.com/us-en/shop/pdp/hp-e14-g4-portable-monitor — BUT it can't power the display, you need to use another c…

The "relevant devices" is surely referring to the displays here. I would love to go DP for everything but the best I can seem to find is computer monitors with 1 DP input and usually 2 or more HDMI. For living room type displays you won't find DP at all.

Re: HDMI Forum rejects AMD's HDMI 2.1 open-source driver

#73

Post by kristjank »

I really hope HDMI snags hit some critical mass and it gets reliquished to the dying TV/home theatre domain where it can rot into obscurity. DisplayPort has its own issues, but they're much smaller than the constant industry fuckups HDMI produces. It's Oracle: the interface.

Re: HDMI Forum rejects AMD's HDMI 2.1 open-source driver

#75

Post by taneliv »

shiroiushi wrote: post #34
taneliv wrote: post #31

Earlier quoted context omitted.

Incompatible licenses would mean that no distribution would have kernels that support it, though. It would be a second class citizen, compiled via DKMS or something, and often broken on a lot of hardware. The difference to broken MP3 support is that if your music file does not play, you can still browse the Internet and write emails and play games, but if your graphics driver is busted, you can do none of those thing…

Why would the licenses be incompatible? AMD owns the code, so they can release it under whatever license they want, including GPL or BSD. They could even put into the public domain if they wanted. AFAICT, the code has not been released at all, so this point about licenses is simply wrong: it doesn't have a license at all right now. As for a broken driver, that's an easy fix I think. From my reading of the article, th…

Exactly like you are saying, if I'm not misunderstanding the situation: the code is unlicensed for anyone who is not AMD. That is incompatible with GPL2 license of the kernel. Without HDMI Forum's approval it can not be licensed, either, since the point is that AMD does not own the secrets contained within.

(If the driver is leaked, I would imagine it to be illegal to distribute it. Companies might elect to not actively support even the fallback mechanism, if it has no other use cases. Probably not a big hurdle and something an installation package should be able to solve, but a hurdle nevertheless.)

Re: HDMI Forum rejects AMD's HDMI 2.1 open-source driver

#77

Post by globular-toast »

ThatPlayer wrote: post #38
vzaliva wrote: post #33

There was a post here on HN some time ago ( https://news.ycombinator.com/item?id=36681814 ), basically explaining that HDMI is terrible and DisplayPort is a much better technical solution. So, perhaps people should favour DP instead of HDMI and gradually switch?

I don't think it's quite that simple. DP is still missing HDMI features like ARC and CEC, which are important for TVs. Even on my personal computer setup, I use the HDMI 2.1 ports on my monitor/GPU over the DP 1.4 ports because the DP port just doesn't have the bandwidth for 2560x1440 @ 240hz with 10-bit colour. That requires ~30 Gbit/s, more than DP1.4's ~26 Gbit/s. Neither my monitor nor my GPU support DP2.0 which…

ARC and CEC are only necessary because of this stupid situation where TVs are like displays with shitty media centres built in. ARC is only a tiny bit more convenient anyway; it's not that hard to run an audio cable back from the TV to an audio receiver and you'll be hiding the cable anyway so it matters not the slightest what it looks like.

In 2002 there was XBMC (later renamed to Kodi). Microsoft even had Windows XP Media Centre Edition in 2005. At that time it was perfectly possible to set up a media centre that could do everything. No need for shitty TV remotes and CEC. You would use a much higher quality remote of your choice. Oh how far we've come in 20 years...

Re: HDMI Forum rejects AMD's HDMI 2.1 open-source driver

#78

Post by account42 »

adrian_b wrote: post #22
shiroiushi wrote: post #17

Earlier quoted context omitted.

It seems the issue with this open-source driver is supporting some of the highest-performance modes of HDMI (like 4K @ 120Hz). Would that even work in a DisplayPort-to-HDMI adapter?

While there are no fundamental reasons for any video mode to not work, most of the DisplayPort to HDMI adapters that are currently on the market do not support the latest standard versions of DisplayPort and/or HDMI, so when a very high performance mode is desired, it might not work. However, the main use of adapters is when you travel and you find in your temporary office an HDMI-only monitor, or when you must use a…

A problem is also that many video cards that do support HDMI 2.1 only support display port DisplayPort 1.4 which has less bandwith. This makes the sitution with the open source AMD drivers even more annoying because even with an active adapter that supports all the required features (which most don't) you can't get the full HDMI 2.1 resolutions/refresh rates that way.

Re: HDMI Forum rejects AMD's HDMI 2.1 open-source driver

#79

Post by Fnoord »

agilob wrote: post #16
shiroiushi wrote: post #10

Earlier quoted context omitted.

>They're handing a win to DisplayPort. Is this useful, if all the relevant devices only have HDMI ports and not DP?

Well, yes. The only relevant device with HDMI that I have is a raspberry pi.

You don't own any monitor or TV?

Re: HDMI Forum rejects AMD's HDMI 2.1 open-source driver

#80

Post by adrian_b »

eqvinox wrote: post #45
adrian_b wrote: post #15

Earlier quoted context omitted.

What I find very annoying is that a very large number of small computers and laptops have both DisplayPort and HDMI, but they have full-size HDMI connectors and only USB Type C DisplayPort. Using Type C for DisplayPort instead of the good full-size DisplayPort connectors is less reliable (easy to disconnect accidentally) and it permits only shorter video cables. More importantly, this blocks the Type C connector, whi…

> The reverse adapters, from HDMI to DisplayPort, are much more expensive and much bulkier, so usually they are not acceptable. That's because those are active converters — contrast DisplayPort has "DP++" which means the source port is electrically capable of transmitting either DP or HDMI signals; the graphics card can switch modes. The adapter is a tiny IC to signal doing that switchover and just wires the data lan…

The DisplayPort connector includes a supply voltage. While it is weaker than in USB, it is strong enough to provide power to an active DisplayPort to HDMI converter, which can have the appearance of a video cable that can connect a DisplayPort source to an HDMI sink.

On one of the HDMI pins there is a DC voltage, but it has other purposes and it is too weak to provide power for a video converter.

This is why an HDMI to DisplayPort converter always requires an additional external power supply.

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