Run niri installed from nixpkgs on non-NixOS distro

[wizetek]

I set out to get niri to run on Linux Mint 22.1 by installing the binary using the Nix package manager. I think that I got all the necessary pieces in place. I start niri-session from TTY but all I get is the dreaded black screen, presumably due to a failure to initialize the GPU. I can still Mod+Shift+e Enter to blindly exit. This happens on an older ThinkPad T440 and a newer ThinkPad P15v.

Initial Nix setup in short

$ gpasswd -a myusername nix-users
$ systemctl enable --now nix-daemon.service
$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable
$ nix-channel --update

Binary niri installation was quick and easy

$ nix-env -iA nixpkgs.niri

Included the relevant paths in ~/.profile for launching

PATH="$HOME/.nix-profile/bin:$PATH"
XDG_DATA_DIRS="$HOME/.nix-profile/share:$XDG_DATA_DIRS"

To get Systemd to co-operate I created ~/.config/systemd/user.conf

[Manager]
ManagerEnvironment="XDG_DATA_DIRS=/home/myusername/.nix-profile/share:/usr/local/share:/usr/share"

$ systemctl --user daemon-reload

I have tried the debug block in config.kdl to directly point render-drm-device to what I have in /dev/dri/.

Not sure if this was needed but I installed nixpkgs mesa which admittedly is newer than the native system's version. I even installed nixpkgs vpl-gpu-rt, vaapiIntel and intel-media-driver for good measure.

My user account is a member of groups: video, render, input.

I can't think of anything else at this point. Any suggestions what to try next?

[YaLTeR]

A common NixOS problem with a black screen is when mesa version from niri mismatches the system mesa version. Maybe that's what's going on here too

[wizetek]

Thanks, that's what I was thinking as well. So the native deb mesa version is 24.2.8, while the nixpkgs mesa is 25.0.2. I didn't even think that it was necessary to install the second nixpkgs instance since the "host" system already provides it. With or without, either way, I get the same outcome.

Something else that got my attention was running niri --session and then seeing

MESA-LOADER: failed to open dri: /run/opengl-driver/lib/gbm/dri_gbm.so: cannot open shared object file: No such file or directory (search paths /run/opengl-driver/lib/gbm, suffix _gbm)

I got past that one by doing export GBM_BACKENDS_PATH=$HOME/.nix-profile/lib/gbm/ but then I hit another wall

WARN niri::backend::tty: error adding device: Unable to obtain a valid EGL Display.

I'm curious if it makes sense to continue trying this "hybrid" installation mixing native deb and nixpkgs environments.

[YaLTeR]

Maybe our nix guru @sodiboo would have some insight on this

[sodiboo]

A common NixOS problem with a black screen is when mesa version from niri mismatches the system mesa version

this is specifically on NixOS, where you have one version of nix mesa "active" and another that the package was built against.

niri-flake's documentation (and sodiboo in general) makes a big fuss about making sure these are in sync, because it's so easy to fuck up and still have it just barely work (until it breaks in some update)

for non-NixOS, my advice has always been "lol, use your distro package" -- configuring using nix module is supported, but i have no idea how to make it work well on non-NixOS and i don't even use that kind of environment so i wouldn't notice if it breaks. if you're determined i can try my best to help you figure it out but honestly just give up.

[sodiboo]

Run niri installed from nixpkgs on non-NixOS distro

why is this opened here and not in e.g. nixpkgs? this is a packaging issue lol

---

anyways have you tried nixGL?

$ nix run --impure github:nix-community/nixGL -- niri

[wizetek]

nixGL wrapper was the answer. Thank you @sodiboo and thank you @YaLTeR for quick and helpful hints.

For completeness sake, this is how I actually got it to work:

$ nix-channel --add https://github.com/nix-community/nixGL/archive/main.tar.gz nixgl
$ nix-channel --update nixgl
$ nix-env -iA nixgl.auto.nixGLDefault

At that point launching nixGL niri-session was successful. The other startup method via nixGL niri --session still requires setting GBM_BACKENDS_PATH.

And here is the minimum required installed nixpkgs list:

$ nix-env -q
mesa-25.0.2
niri-25.02
nixGL

Alacritty, Fuzzel, Waybar, and others can live on the host system (deb) or may be added via nixpkgs as well, whatever the user's preference (versions, features, bugs).

Mission accomplished. Now if anyone wants to run niri on any distro where it's not packaged, this is a viable option.