Now that the per-capture worker subprocess makes an NVENC EGL/CUDA driver fault survivable (design/zerocopy-worker-isolation.md), the reason the NVENC zero-copy path stayed opt-in is gone. zerocopy::enabled() now defaults ON for both GPU backends (was ON VAAPI / OFF NVENC). Fallbacks are intact: VAAPI's one-shot CPU auto-downgrade (VAAPI-gated, never trips for NVENC) and NVENC's per-capture fallback + worker-death latch. Reframe the shipped host.env examples and setup guides to rely on the default rather than force PUNKTFUNK_ZEROCOPY=1 (an explicit =1 skips the VAAPI auto-downgrade). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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title, description
| title | description |
|---|---|
| GNOME (Mutter) | 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, Fedora, or Arch.
New here? Read Security & Safe Use first — a streaming host is remote control of the machine, so keep it on a trusted LAN or VPN and require pairing.
host.env
Write ~/.config/punktfunk/host.env with the GNOME settings. The host auto-detects the compositor
from your session, so the explicit PUNKTFUNK_COMPOSITOR is belt-and-braces:
# ~/.config/punktfunk/host.env
WAYLAND_DISPLAY=wayland-0
XDG_CURRENT_DESKTOP=GNOME
PUNKTFUNK_COMPOSITOR=mutter
PUNKTFUNK_VIDEO_SOURCE=virtual
# GPU zero-copy (dmabuf → CUDA → NVENC) is ON by default; auto-falls back to CPU. Set =0 to force CPU.
PUNKTFUNK_INPUT_BACKEND=libei
You must be on a Wayland session (not X11), and Mutter must be ≥ 48. See the Configuration reference 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/Debian 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:
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, Fedora, 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:
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:
systemctl --user enable --now punktfunk-host
journalctl --user -u punktfunk-host -f # watch it come up and print its identity fingerprint
Then bring up The Web Console to arm pairing and connect a client. For an always-on box, see the headless session below.
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:
# /etc/gdm3/custom.conf (Ubuntu) · /etc/gdm/custom.conf (Fedora)
[daemon]
AutomaticLoginEnable = true
AutomaticLogin = your-user
Disable the lock (see above), then enable the host user service and let it linger past logout:
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.
Troubleshooting
More fixes — black screen, discovery, pairing — in Troubleshooting.
Once the host is up, bring the console up and pair — see The Web Console.