Photograph of a bunch of HDMI cables tied together in Lafayette, California, November 13, 2020. (Photo by Smith Collection/Gado/Getty Images)
The HDMI Forum, the licensing group that oversees the HDMI standard, has notified AMD that it does not allow open source implementations of the HDMI 2.1 (or HDMI 2.1+) specification, blocking tools such as AMD’s FreeSync from working over HDMI connections at resolution/frequency combinations such as 4K at 120Hz or 5K at 240Hz.
This can be a problem for Linux users in terms of getting the highest resolution image to the highest frame rate display, at least when it comes to HDMI connections.
In January 2021, the Linux blog Phoronix noted that the HDMI Forum does not offer public access to the HDMI 2.1 specification. Alex Deucher, an AMD engineer who has been involved in the development of the company’s open source offerings for a long time, has been maintaining the thread for at least two years and has now reported a negative result, transmits ArsTechnica.
In February 2023, Deucher reported that «is working with our [AMD] legal team to figure out what we can do while still meeting our obligations to the HDMI Forum». Two months later, he reported that AMD had launched «with core functionality, now we have to go through each feature with the legal department and determine if we can disclose them without violating our obligations to». The summer and fall of 2023 passed and the legal due diligence was still ongoing, and in October the decision was «in the hands of the HDMI Forum».
Deucher has now proposed the current resolution:
Unfortunately, the HDMI Forum rejected our proposal. At this time, an open source implementation of HDMI 2.1 is not possible without violating the requirements of the HDMI Forum.