Trying out NixOS on a System76 Oryx Pro. Happily, got reasonably far before finding something broken; my laptop doesn’t appear to detect a new device on the HDMI port.
I suspect there’s a cleaner way to determine whether the system is detecting a new device on the HDMI port, but the way I’m currently doing so is with xrandr:
If I understand right, the Oryx has two display adapters – one Intel, one Nvidia.
I have a hunch that the external display is connected to a different adapter than the laptop’s monitor, and that the driver for that other adapter isn’t loaded.
If you’re lucky, it may be as simple as loading the nvidia driver.
services.xserver.videoDrivers = [ "nvidia" ];
You could also try some of the prime/optimus solutions documented on the Nvidia page in the NixOS Wiki. I’ve had decent luck with prime on some of my devices, but never attempted to make it work with external displays.
Did you ever figure this out? I’m struggling with the same problem. I’ve added nvidia to videoDrivers but still no luck getting an external monitor working.