The HDMI standard is essentially ubiquitous more than 20 years after its debut. It's so common that it can be easy to forget that it's a proprietary standard—which can be a problem for fans of free open source software. AMD has been hoping to give a gift to the Linux faithful in the form of an open source HDMI driver, but that quest appears to be ending. The HDMI Forum has reportedly rejected AMD's legal justification, forcing it to keep the driver under wraps.
The HDMI Forum was set up in 2002 by companies like Sony, Panasonic, and Maxell, but it now has nearly 100 members. The Forum's job is to oversee the development and licensing of the HDMI standard, and it doesn't allow open access to the technology. That has been a thorn in the side of the most demanding Linux desktop users. If you want to drive a 4K or 5K monitor at high refresh rates over HDMI, you're out of luck.
AMD, a long-time member of the Forum, has been working on an open source version of the HDMI 2.1 specification since last year. That's when AMD developer Alex Deucher announced that AMD's legal team was working to determine what features the company could deliver without running afoul of its obligations to the Forum. With such a driver, AMD's open FreeSync standard could work over HDMI with high resolution and refresh.
As of late 2023, AMD had submitted its request to the HDMI Forum and was waiting for a decision. Deucher has posted an update on an issue tracker thread he's kept open for three years, and it's bad news. The Forum has rejected AMD's request, and Deucher does not believe there's a way to release the open HDMI 2.1 driver without getting AMD in hot water. The thread has attracted dozens of new replies from disappointed Linux users decrying the Forum's stubbornness.
Precisely what rules AMD would breach if it released the driver is unclear. According to Ars Technica, Forum members pay a $15,000 annual fee, but none of the publicly available documentation strictly forbids creating an open version of the specification. However, the HDMI Forum's source code license is rather restrictive. Some commenters in the issue tracker have speculated that the Forum could be concerned about ripping protected video streams. Still, digital pirates hardly need an open HDMI driver to rip video content.
This might be the nail in HDMI's coffin as far as Linux users are concerned. DisplayPort is a newer standard with better output support on Linux. AMD could implement new HDMI features in closed source drivers or binary blobs, but Deucher has not said how or if the project will move forward.
