enricobuehlerandClaude Opus 5
b297542c4d
A controller that reaches the host by USB passthrough — VirtualHere and friends, or simply a pad plugged into the host — arrived there twice: once as the real device, once as the virtual pad this client built from the same hands. Games read both, so a stick drifts against the centred second pad and menus take every input twice. New per-client setting, "Forward controllers", default on (today's behaviour). It is tier-P, so a profile can decline what another profile forwards. On Linux and Windows it is deliberately stronger than "send nothing". Opening a controller is what CLAIMS it — SDL's HIDAPI drivers take the device node — and a claimed device is one a passthrough tool cannot bind, so with this off the session opens no slot at all and never enables the Valve HIDAPI drivers. Menu navigation is untouched: the launcher still opens the active pad, and a session supersedes menu mode whether it forwards or not, so the pad is free for the whole time a stream is up. The consequence, documented at both the setting and the chord: the controller escape chord is read off forwarded pads, so it is unavailable there. The Apple and Android input stacks claim nothing, so those clients keep their slots and their chords and only gate the wire sends — losing tvOS's only controller way out of a stream would have been the worse bug. Android does stop its DualSense and Steam Controller 2 USB captures, which do claim the device. Surfaces: GTK, WinUI, the console settings screen, Apple's touch and gamepad settings, the Android touch and gamepad settings, and Decky (which also hides the rows that now have nothing to act on). Everywhere the "which pad" and "pad type" rows grey out while it is off. Verified: cargo clippy --all-targets -D warnings + 79 tests on pf-client-core, pf-console-ui, punktfunk-client-session and punktfunk-client-linux (linux/amd64 container, gate proven non-vacuous with a planted error); swift build for the Apple clients; gradle compile + 49 unit tests for Android (likewise proven); tsc for Decky. clients/windows is UNCOMPILED — both Windows boxes were offline; its edits were reviewed against the helper signatures by hand. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Punktfunk — Steam Deck plugin (Decky)
Stream to your Steam Deck without ever leaving Gaming Mode. This
Decky Loader plugin adds a Punktfunk panel to the Quick Access Menu
(the … button): discover hosts on your network, pair with a PIN, tweak stream settings, and launch
a fullscreen, gamescope-focused stream — all from the couch, gamepad-navigable.
The video itself is the native GTK4 Linux client (the io.unom.Punktfunk flatpak); the plugin
discovers, pairs, configures, and launches it the right way so gamescope fullscreens it — the same
Steam-shortcut trick MoonDeck uses. Because it's built from real Steam UI primitives (@decky/ui),
the panel looks and feels native to Gaming Mode.
What it does
- Discover — browses the LAN over mDNS for Punktfunk hosts, in both the QAM panel and a fullscreen page; each host row opens a details view (address, pairing policy, certificate fingerprint to cross-check against the host's log).
- Pair — for a host that requires it, a gamepad-navigable PIN keypad runs the SPAKE2 pairing ceremony headlessly, then remembers the host so future streams connect silently.
- Stream — launches fullscreen via a branded "Punktfunk" Steam shortcut so gamescope focuses it.
- Games — each host row has a games button that opens its library picker: pin titles as one-tap "Stream " rows in the QAM (jump straight into e.g. Playnite on the host), or "Open library on screen" to launch the client's controller-driven, console-style library browser (aurora backdrop + poster coverflow; A plays, B returns to Gaming Mode). Pins survive plugin reinstalls (stored next to the client's config) and follow a host across IP changes (matched by certificate fingerprint).
- Settings — resolution / refresh / bitrate / gamepad type / host compositor / mic, written to the client's config.
- About — plugin version, an explicit "Check for updates" button, the setup-guide link, and a force-stop for a wedged stream client.
To leave a stream: the in-client controller chord (L1 + R1 + Start + Select), or close the "game" from the Steam overlay — either returns you to Gaming Mode.
Install on the Deck
You need Decky Loader and the io.unom.Punktfunk flatpak
(packaging/flatpak) installed on the Deck — SteamOS /usr is
read-only, so the flatpak (which bundles libadwaita/SDL3) is the canonical client. Discovery uses
avahi-browse, which ships on SteamOS/Bazzite.
Recommended — install from URL (published by CI): in Decky → Settings → Developer Mode → Install Plugin from URL, paste:
https://unom.io/pf-decky
(short link for https://git.unom.io/api/packages/unom/generic/punktfunk-decky/latest/punktfunk.zip;
for a pinned version use https://git.unom.io/api/packages/unom/generic/punktfunk-decky/<version>/punktfunk.zip
directly). The plugin then self-updates without
the Decky store — when a newer build exists, an Update button appears and drives Decky
Loader's own (SHA-256-verified) install. Installs and updates can take a couple of minutes on some
networks: Decky's installer also contacts its plugin store first, which may be slow or blackholed
before the actual download proceeds.
Updating the client
The plugin also reports — and where it can, installs — updates for the client it launches. What is possible depends on how that client was installed, and the About tab names the install kind so the answer is never a mystery:
| Install | Update |
|---|---|
| Flatpak (the usual Deck client) | One tap. flatpak update --user io.unom.Punktfunk — a per-user install, which is why sudo flatpak update never touches it. |
| .deb / .rpm (and rpm-ostree, which stages for the next reboot) | One tap, after an explicit opt-in: sudo usermod -aG punktfunk-update $USER. The tap starts a fixed, parameterless root oneshot (punktfunk-client-update.service) through polkit — nothing about the request is attacker-influenceable, and the payload comes from your distro's own signed repositories. |
| pacman | Same, plus the root-owned PACMAN_FULL_SYSUPGRADE=1 in /etc/punktfunk/update.conf — a partial upgrade is against Arch doctrine, so the only thing the helper will run is a full pacman -Syu. |
| sysext, nix, a source build | The plugin shows the command and stops. There is no feed behind those installs, and a button that can only fail is worse than one honest line. |
Whether a newer client exists is the client's own answer (punktfunk-client --check-update),
read from the Ed25519-signed per-channel manifest the host's update check already trusts —
PUNKTFUNK_UPDATE_CHECK=0 disables the check, PUNKTFUNK_UPDATE_APPLY=0 keeps the check but
never offers to install. A client too old to have that mode is reported as such rather than as
up to date.
Build & sideload (development)
cd clients/decky
pnpm install
pnpm build # rollup → dist/index.js
pnpm run package # → out/punktfunk/ + out/punktfunk-v<ver>.zip
DECK=deck@<deck-ip> pnpm run deploy # rsync → /tmp, sudo-install into the root-owned plugins dir, restart loader
~/homebrew/plugins/ is root-owned (the loader runs as root), so deploy.sh stages to a temp dir
then sudo-installs and restarts the loader — set DECKPASS=… to run it non-interactively. A loader
restart is required for an out-of-band install to appear.
Architecture
| File | Role |
|---|---|
src/index.tsx |
Plugin entry: the QAM panel + route registration. |
src/page.tsx |
The /punktfunk fullscreen page — Hosts (with per-host details) / Settings / About tabs. |
src/settings.tsx · src/pair.tsx |
Stream-settings section; the gamepad-navigable PIN-pairing modal. |
src/library.tsx |
The per-host game picker (pin/unpin, "Open library on screen") + the pinned-game launch helper. |
src/hostmgmt.tsx |
Add / edit host dialogs — mutate the shared known-hosts store (client-known-hosts.json) via the flatpak client's headless modes, so a host saved here shows up in the desktop client too. |
src/ui.tsx |
Shared UI primitives for the fullscreen page + modals (right-aligned row actions, consistent Field layout). |
src/hooks.ts · src/boundary.tsx |
Shared discovery/update/pins hooks + actions; the render error boundary. |
src/steam.ts |
Steam-shortcut launch (AddShortcut / SetAppLaunchOptions / RunGame) — the focus-correct stream start. The shortcut's exe is /bin/sh with the wrapper passed as an argument, so the script never needs an exec bit (Decky's zip extraction drops it and the root-owned plugins dir can't be chmodded by the unprivileged backend). Launch extras ride env-prefix tokens: PF_LAUNCH=<id> (pinned game) / PF_BROWSE=1 + PF_MGMT=<port> (on-screen library); ids are validated space/quote-free at pin AND launch time. |
src/backend.ts |
Typed callable bridges to main.py. |
bin/punktfunkrun.sh |
The launch wrapper the Steam shortcut runs (so the window is focusable); maps PF_LAUNCH/PF_BROWSE/PF_MGMT to --launch/--browse/--mgmt. An older flatpak ignores the flags harmlessly (plain stream / hosts page). |
main.py |
Backend: discover (via avahi-browse) / pair / library (headless flatpak --library, TSV) / pins store (decky-pinned.json) / settings / kill_stream / check_update (with an explicit CA-bundle search — Decky's embedded Python has no usable default TLS roots on SteamOS). |
scripts/test-backend.py |
Stdlib-only checks for the backend's pure parsers (TSV, error classes, avahi TXT) + the pins round trip. |
plugin.json · update.json |
Decky manifest; CI-baked update channel. |
Limitations / next steps
- No manual "add host by IP" entry yet (discovery is mDNS-only).
- No in-stream overlay inside the plugin — the client owns the session once launched.
- Pairing needs the operator to arm pairing on the host so it shows the PIN; the plugin can't arm it remotely.
Related
- Documentation — Steam Deck setup guide
- Linux client — the app this plugin launches
- Project README — the host, the other clients, and how it all fits together