The building blocks that were still missing from AMDGPU’s modern HDMI implementation are finally arriving on the Linux side. If the series of patches goes through to the end, Valve’s Steam Machine could no longer be limited to 4K 60 Hz on its HDMI port.
HDMI 2.1: AMD adds DSC to the Linux display stack
According to information spotted by Phoronix, the latest round of HDMI 2.1 patches for the open source driver AMDGPU now includes the Display Stream Compressionor DSC. This addition completes the work already undertaken by AMD around the Fixed Rate Linkor FRL.
FRL and DSC serve two distinct functions. FRL replaces signaling path TMDS inherited from HDMI 2.0 and becomes necessary for higher bandwidth modes. DSC compresses the video stream with a so-called visually lossless method, in order to reduce the volume of data transmitted by the cable.
Combined, these two mechanisms make it possible to consider modes like 4K Ã 240 Hz or 8K Ã 120 Hzprovided the graphics card, display and cable are all compatible. This is precisely what AMDGPU was still missing to expose a more complete part of the HDMI 2.1 functions under Linux.
What this could change for SteamOS and the Steam Machine
The patch cover letter indicates that FRL and FRL DSC fixes should join the next round of updates AMDGPU Display Core. Phoronix expects integration into the main core during the cycle Linux 7.2.
The subject is of direct interest to Valve. The company had already confirmed that the Steam Machine’s hardware could handle HDMI 2.1, but that SteamOS could not expose all of its functions, due to the limitations of the open source driver and licensing constraints linked to the HDMI Forum.
If these patches are well integrated and then included in SteamOS, the machine would no longer be limited to HDMI 2.0 specifications, i.e. 4K Ã 60 Hz. She could aim 4K Ã 120 Hzeven 4K Ã 240 Hz with DSC activated. The point is all the more interesting as the DisplayPort 1.4 of the machine already supports the 4K Ã 240 Hz avec DSC.
At this stage, there is no evidence to confirm that AMD’s efforts are specifically targeting the Steam Machine. The schedule, however, remains consistent: once FRL and DSC are present in AMDGPU, Valve would finally have the technical elements necessary to align the HDMI output with what the hardware already knows how to do on paper.
Source : VideoCardz
