---
title: GNOME (Mutter)
description: Configure a Punktfunk host for GNOME — host.env, the EGL/lock traps, and a headless session.
---

Configure a host running **GNOME**. The host drives GNOME's Mutter compositor to create a per-client
virtual display over D-Bus (`RecordVirtual`), zero-copy. This page assumes the host is already
installed — see [Ubuntu](/docs/ubuntu), [Fedora](/docs/fedora), or [Arch](/docs/arch).

> New here? Read [Security & Safe Use](/docs/security) first — a streaming host is remote control of
> the machine, so keep it on a trusted LAN or VPN and require pairing.

## host.env

The host auto-detects the compositor from your live session on every connect, so the starter
`~/.config/punktfunk/host.env` is one line:

```ini
# ~/.config/punktfunk/host.env  (keys are case-sensitive)
PUNKTFUNK_VIDEO_SOURCE=virtual
# GPU zero-copy (dmabuf → CUDA → NVENC) is ON by default; auto-falls back to CPU. Set =0 to force CPU.
```

> **Don't set `PUNKTFUNK_COMPOSITOR`, `WAYLAND_DISPLAY`, or `XDG_CURRENT_DESKTOP` here.** Pinning
> the compositor turns auto-detection **off** — per connect *and* mid-stream — so the host stops
> following session switches, and stale session values point it at dead sockets. Forcing a backend
> is a CI / dedicated-appliance posture, not desktop configuration.

You must be on a **Wayland** session (not X11), and Mutter must be **≥ 48**. See the
[Configuration reference](/docs/configuration) for every option.

## The GL/EGL userspace

On NVIDIA, gnome-shell fails to start — or the host logs **"GPU … not supported by EGL"** — when the
NVIDIA GL/EGL userspace is missing. The base driver package doesn't always pull it in. Install your
distro's NVIDIA GL/EGL userspace package — on **Ubuntu** it's `libnvidia-gl-<version>` matching
your driver; on **Fedora/Arch** it ships with the RPM Fusion / repo driver — then confirm the glvnd
vendor file exists:

```sh
ls /usr/share/glvnd/egl_vendor.d/10_nvidia.json    # must exist
```

Installing the driver itself is covered on your distro's install page
([Ubuntu](/docs/ubuntu), [Fedora](/docs/fedora), [Arch](/docs/arch)).

## Do not lock the session

A **locked** GNOME session blocks screen capture — the host fails with
**"Session creation inhibited"**. On an always-on or headless host there's no one to unlock it, so
disable the lock:

```sh
gsettings set org.gnome.desktop.screensaver lock-enabled false
gsettings set org.gnome.desktop.session idle-delay 0
```

## Start the host

With `host.env` in place, start the host from **inside your GNOME session**:

```sh
systemctl --user enable --now punktfunk-host
journalctl --user -u punktfunk-host -f   # watch it come up and print its identity fingerprint
```

This unit runs the secure native-only host. To also serve stock [Moonlight](/docs/moonlight)
clients, GameStream compat is opt-in (`PUNKTFUNK_GAMESTREAM=1` in `host.env`, trusted LANs only) —
see [What the unit starts](/docs/running-as-a-service#what-the-unit-starts).

A desktop-login host should also follow your session's lifetime, or restarting GNOME Shell leaves the
host wired to a compositor that is gone — it keeps answering, and every session after that fails at
capture. Add the drop-in from
[Restart the host with your desktop](/docs/running-as-a-service#restart-the-host-with-your-desktop).
Skip it on the headless route below.

Then bring up [The Web Console](/docs/web-console) to arm pairing and connect a
[client](/docs/clients). For an always-on box, see the [headless session](#headless-session) below.

Display scaling you set while streaming **sticks per client**: the host remembers each device's
scale and reapplies it on reconnect — see
[Persistent scaling](/docs/virtual-displays#persistent-scaling).

## HDR (GNOME 50+)

The per-client virtual display this page is about always streams **SDR** — Mutter's `RecordVirtual`
screencasts are 8-bit upstream, so there is nothing to turn on.

GNOME 50 added HDR screencast for **real monitors**, and the host can use that route — on the
GameStream/Moonlight plane only, by mirroring a monitor instead of creating one.
[HDR → Linux + GNOME](/docs/hdr#linux--gnome) has the two settings it needs, which monitor it
checks, and how it degrades when none is in HDR mode; [Check it](/docs/hdr#check-it) has the
`hdr-probe` subcommand that names the link that said no.

## Headless session

To run with no monitor and no login, keep a GNOME Wayland session up at all times and start the host
without a login. Have GDM auto-login your user:

```ini
# /etc/gdm3/custom.conf  (Ubuntu)   ·   /etc/gdm/custom.conf  (Fedora)
[daemon]
AutomaticLoginEnable = true
AutomaticLogin = your-user
```

Disable the lock (see [above](#do-not-lock-the-session)), then enable the host user service and let it
linger past logout:

```sh
systemctl --user enable --now punktfunk-host
sudo loginctl enable-linger "$USER"
```

Reboot and the host comes up on the auto-login session. Full walkthrough:
[Running as a Service](/docs/running-as-a-service).

## Troubleshooting

More fixes — black screen, discovery, pairing — in [Troubleshooting](/docs/troubleshooting).

Once the host is up, bring the console up and pair — see [The Web Console](/docs/web-console).
