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. ...

September 12, 2026 · 18 min

HyperHDR Ambient Lighting: My TV Backlight Rig

The Goal Ambient lighting (you may know it as bias lighting, or by Philips’ “Ambilight” brand) puts an LED strip around the back of the TV and lights it to match the edges of whatever is on screen: a forest scene spills green onto the wall behind the panel, an explosion throws orange. Beyond looking good, a lit wall behind the TV reduces eye strain in a dark room and makes the picture feel larger than the panel. ...

June 7, 2026 · 13 min