AMDGPU HDMI 2.1 patches add DSC support for Linux
AMD is preparing another update for its open-source AMDGPU Linux driver. According to Phoronix, the latest HDMI 2.1 patch series now includes Display Stream Compression support, also known as DSC.
HDMI 2.1 FRL and DSC are two separate technologies used to increase display bandwidth. FRL, or Fixed Rate Link, is the newer HDMI signaling mode required for higher bandwidth modes beyond HDMI 2.0. DSC, or Display Stream Compression, reduces the amount of data sent over the cable using visually lossless compression. Together, they allow modes such as 4K at 240Hz and 8K at 120Hz over HDMI when supported by the GPU, display and cable.
HDMI 2.1 DSC & FRL, Source: Freedesktop
This follows AMD’s earlier HDMI 2.1 Fixed Rate Link patches for AMDGPU. FRL replaces the older TMDS signaling path used by HDMI 2.0 and is required for higher HDMI bandwidth on modern displays. DSC adds another part of the HDMI 2.1 feature stack. It enables higher resolution and refresh rate modes by using visually lossless compression. Examples include 4K at 240Hz and 8K at 120Hz.
The patch cover letter reportedly says the HDMI FRL and FRL DSC patches should land with the next AMDGPU Display Core patch series. Phoronix expects the code to reach the mainline Linux kernel during the Linux 7.2 cycle.
Steam Machine liekly to benefit
This is related to our earlier coverage of HDMI 2.1 limitations on SteamOS and the Steam Machine. Valve previously confirmed that the hardware can support HDMI 2.1, but SteamOS could not expose the full feature set due to open-source driver and HDMI Forum licensing restrictions.
Official Steam Machine display specs, Source: Valve
Should everything go as suggested, Steam Machine could now gain full HDMI 2.1 functionality through a future SteamOS update. The system will not be limited to 4K 60 Hz (on HDMI 2.0 specs). By turning to HDMI 2.1, the system will support 4k 120Hz and up to 4K 240Hz with DSC enabled. Worth adding that the system already offers DisplayPort 1.4 which also supports 4K 240Hz with DSC already. In other words, should the Linux patch be included in linux AMGPU update, Steam could enable 4K 240Hz support through both display connectors.
Of course, we are just speculating, Valve has never confirmed that the ongoing effort from AMD engeering is for Steam Machine, but the itming is definately interesting.
Source: Phoronix
