Valve: HDMI Forum Continues to Block HDMI 2.1 for Linux

Posted by OsrsNeedsf2P 1 day ago

Valve: HDMI Forum Continues to Block HDMI 2.1 for Linux(www.heise.de)

870 points | 470 commentspage 3

Asmod4n 1 day ago|

Couldn’t AMD just release that as firmware/binary blob and call that from the open source driver to circumvent the issue?

waysa 1 day ago||

Adapting DP to HDMI using the Synaptics VMM7100 chip is apparently the best (most feature complete) workaround for now. It's the same one that Intel uses in their Arc GPUs.

preisschild 1 day ago|

Is this the one in the Cable Matters 102101-BLK DP->HDMI adapter?

blastersyndrome 1 day ago||

Legally speaking, what is stopping someone from just reverse-engineering the specification and publishing it online somewhere?

superxpro12 1 day ago||

Probably a lawyer with little legal standing that is however funded by a very large checkbook.

Avamander 1 day ago||

I suspect there isn't anything really stopping them (especially in the EU) except threats.

Aachen 1 day ago||

Article without GDPR-noncompliant consent wall: https://archive.is/8ED2m

irusensei 1 day ago||

For PCs I go for DisplayPort or USB-C on devices nowadays. The DisplayPort connector has the advantage of being good with a clipping mechanism.

modeless 1 day ago||

This is fundamentally about DRM, isn't it? There is a working open source implementation already, but the HDMI cartel won't allow an open source implementation to have the encryption keys required to interface with the DRM in existing devices?

jsheard 1 day ago|

Source devices aren't required to output a DRM'ed signal though, are they? I think the DRM is only required on the receiver side. In that case a compliant source wouldn't need any keys, and besides, that wasn't a blocker for the previous HDMI versions which supported DRM too.

modeless 1 day ago||

IIUC they're required to do a handshake involving encryption. Which is a form of DRM to enforce centralized control over the device ecosystem even if the subsequent video signals are not encrypted.

janc_ 22 hours ago||

That sounds like an anti-competitive action by a near-monopoly player…

freeopinion 1 day ago||

I always choose DP. I didn't even know there was this issue with HDMI.

jonny_eh 1 day ago||

Is the a USB-C/Thunderbolt to HDMI 2.1 dongle? Send Displayport and audio over USB-C and then let that hardware handle the HDMI handshaking.

klipklop 1 day ago|

There isn't one that supports VRR/Gsync/Freesync well. What gamers want is chroma/RGB 4:4:4 + HDR + VRR/Freesync + 4k,120hz for their Linux PC on a TV. This is not possible with any DP --> HDMI 2.1 dongle on the market. They need support at the driver level to make this work. This is what the idiots at the HDMI forum are blocking. The only way to have high quality visuals on a PC/TV setup is to run Windows. That really sucks.

sunshowers 1 day ago|||

I do actually have this setup going with a Cable Matters adapter [1] + a custom firmware I found [2] and

> chroma/RGB 4:4:4 + HDR + VRR/Freesync + 4k,120hz for their Linux PC on a TV

works great now on my LG C4 TV with Bazzite's gaming mode, though:

* 144Hz is unstable

* 12-bit color is unstable (10-bit works fine), and gamescope doesn't have a way to limit color depth (kwin does), so I had to put in place an EDID override

* in the EDID, limiting the FreeSync range to 60-120Hz (which should still allow frame doubling/tripling) seemed to be better -- the default 40Hz caused a bit of flickering because the AMD driver would drop the refresh rate down to 38.5Hz or so.

Should write about this in more detail.

[1] https://www.amazon.com/dp/B094XR43M5

[2] https://forum.level1techs.com/t/it-is-possible-to-4k-120-hdr...

klipklop 1 day ago||||

I can't edit now, but it seems that there is a new dongle on the market that might be able to do this with some changes (whitelists?) to the AMDGPU driver in Linux.

Fire-Dragon-DoL 1 day ago|||

This is terrible.

Aren't there on the market big "pc monitors" instead of tvs?

raggi 1 day ago||

Not with good measured performance no. There are some which advertise good numbers (such as high refresh rates) but are unable to drive the panels to visibly change pixels at anywhere near the refresh rate.

agoodusername63 1 day ago|

I just use a DisplayPort to hdmi cable. Works well on my 4k@120 TV

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