HDMI 2.1 on Linux with a DP-to-HDMI PCON, and Feeding gamescope to HyperHDR
The Goal The TV in my living room is an LG OLED65C5: 4K at 120 Hz, VRR, ALLM. The gaming PC that drives it is the one from the Linux Multi-Seat Gaming series - a Radeon RX 9070 XT running Steam Big Picture in a dedicated gamescope session, started and stopped as a systemd user unit (Part 3 is where that design settled, seats and all). The session script has asked for -r 120 --adaptive-sync since Part 1. The TV had been quietly giving me 4K60 with no variable refresh the whole time. ...