Although the HDMI Forum last week rejected AMD's proposal to implement HDMI 2.1+ features in open-source drivers, it looks like the open-source Nouveau driver for Nvidia's GPU will receive a warm reception by the standard-setting organization, reports Phoronix. As a result, advanced HDMI capabilities will work on Nvidia-based graphics cards under Linux. There is a catch though.
Nouveau is an open-source graphics device driver for Nvidia graphics cards, which provides an open-source alternative to Nvidia's own driver. Nouveau supports a wide range of Nvidia GPUs and fully supports 2D and 3D acceleration, video playback, and power management, which allows to take full advantage of some of the best graphics cards around. However, when it comes to HDMI and some other features, Nouveau relies closed-source firmware.
As a result, Karol Herbst, a long-time contributor to the Nouveau project, believes that since Nvidia's closed-source driver already supports HDMI 2.1, there is no reason to believe that Nouveau cannot achieve similar support as much of the display functionality handling in Nouveau is managed by Nvidia's closed-source firmware binaries.
"Even though AMD might not be able to add support for HDMI 2.1 [to open-source Linux drivers], Nouveau certainly will as Nvidia's open source driver also supports HDMI 2.1 so there is no reason to believe that at least some drivers can't support HDMI 2.1," Herbs wrote at Mastodon. "It is quite backwards, but apparently having all the logic inside firmware (like Nvidia does) will probably help us implementing support for HDMI 2.1."
It should be noted that the integration of HDMI 2.1+ functionality has yet to occur in Nouveau. Nvidia's own kernel driver implements HDMI 2.1 functionality through the use of GSP firmware blobs. This approach allows for a separation of proprietary and open-source components, enabling the Nouveau driver to potentially adopt a similar method for HDMI 2.1 support. The integration of HDMI 2.1 functionality into Nouveau would depend on the ability to utilize these firmware blobs effectively though.
AMD has been trying for three years to enable support for 4K@120Hz and 5K@240Hz through HDMI 2.1 for Linux users. The HDMI Forum limits public access to its specifications, allowing only authorized manufacturers and developers to access the technical details needed to implement HDMI features in their products (and pay royalties to the developers of these technologies). While this decision ensures the quality and consistency of the HDMI experience, it significantly impedes the support for open-source drivers. Nvidia has a different approach to Linux drivers by essentially closing details of HDMI 2.1 features implementation from the open-source community.
