KDE Plasma (KWin)

Configure a punktfunk host on KDE Plasma. The host uses KDE's KWin compositor to create a per-client virtual display, captured zero-copy on NVIDIA. This page assumes the package is already installed — see Ubuntu, Fedora, Arch, or the Bazzite appliance.

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

The host auto-detects your KWin session on every connect — including a box that switches between the Plasma desktop and Steam Game Mode — so the starter ~/.config/punktfunk/host.env is one line:

# ~/.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 a switch to Game Mode then kills the stream instead of being followed, and stale session values point the host at dead sockets. Forcing a backend is for CI and dedicated appliances (the headless session below ships a host.env.kde that pins on purpose).

If the box switches between the desktop and Game Mode, also enable lingering — the host is a user service, and without linger the logout moment of a session switch tears it (and PipeWire) down mid-stream:

sudo loginctl enable-linger "$USER"

See the Configuration reference for every option.

Use a Wayland session

KDE must run on Wayland, not X11 — pick the Wayland session from the picker on the login screen. The virtual-display path is Wayland-only and will not come up under X11.

KWin must be 6.5.6 or newer (virtual outputs land there). Check with:

kwin_wayland --version

Streaming the interactive desktop

To stream a logged-in Plasma desktop (rather than a headless session, below), KWin has to hand the host its restricted screencast protocol. The host package ships an io.unom.Punktfunk.Host.desktop file whose X-KDE-Wayland-Interfaces grants exactly that on a normal interactive session (least-privilege, the same mechanism krfb/krdp use). After a fresh install, log out and back into the Desktop session once so KWin re-reads the grant.

A normal KDE login still lacks the RemoteDesktop grant that input injection needs — without it the host pops an "Allow remote control?" dialog no headless box can answer. Fedora and Bazzite ship a one-shot helper that seeds it (run once as the streaming user, no root):

bash /usr/share/punktfunk/bazzite/kde-desktop-setup.sh    # Fedora / Bazzite

The .deb and Arch packages don't include that wrapper. Seed the grant by hand instead — copy the shipped kde-authorized file into the portal store (the share dir is /usr/share/punktfunk-host on Debian/Ubuntu, /usr/share/punktfunk on Arch), then log out and back in:

mkdir -p ~/.local/share/flatpak/db
cp /usr/share/punktfunk*/headless/kde-authorized ~/.local/share/flatpak/db/kde-authorized

A login-less appliance skips all of this — its headless session (below) needs none of these grants.

Start the host

With host.env in place, start the host from inside your Plasma 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. To start at boot — including fully headless — see the headless session below or Running as a Service.

Persistent per-client scaling

KWin round-trips per-client display scale: it names each session's virtual output per client, so a scale you set for one client (150 %, 125 %, …) is reapplied on that client's next connect. See Virtual displays.

Headless session

For a login-less appliance — a box that streams at boot with no graphical login — the host brings up a dedicated headless KWin session rather than relying on an interactive one. It runs its own kwin --virtual session (shipped as the punktfunk-kde-session.service unit) with permission checks relaxed, so it needs none of the interactive grants above.

mkdir -p ~/.config/punktfunk
cp /usr/share/punktfunk/host.env.kde ~/.config/punktfunk/host.env   # Debian/Ubuntu: /usr/share/punktfunk-host/host.env.kde

systemctl --user daemon-reload
systemctl --user enable --now punktfunk-kde-session punktfunk-host
sudo loginctl enable-linger "$USER"

The session unit brings up headless KWin; the host unit follows it and starts listening. See Running as a Service for the full headless setup.

Troubleshooting

• KWin too old: virtual outputs need KWin ≥ 6.5.6. Check with kwin_wayland --version.
• Black screen / no picture: confirm you're on a Wayland session (not X11) and the NVIDIA GL userspace is installed. More in Troubleshooting.

To bring the console up and pair, see The Web Console.