enricobuehler
3c096835c2
Field triage on Nobara, 2026-08-09. Every connect degraded to ATTACH — which on that box mirrors a
game-mode session the host never configured, and looked like a black screen on every connect. The
host said:
the packaged pf-dm-helper polkit action is missing or was denied (reinstall the punktfunk
package, or install the display-manager polkit rule from the docs)
Every clause of that was wrong. The action was installed, `allow_any`, and its exec.path annotation
matched the installed helper; pkexec authorized it and RAN the helper. The helper refused, and said
exactly why:
pf-dm-helper: user 'nobara-user' is not in the 'punktfunk' group — refusing.
Grant it with: sudo usermod -aG punktfunk nobara-user (then re-login)
That text never reached the log, because `dm_helper` ran the helper with `.status()` — which
discards stderr and collapses the exit code to a bool. The one thing that would have ended the
investigation in seconds was thrown away at the call site, and the caller then guessed. Neither
suggested remedy adds anyone to a group, so a reader who followed both stayed broken and learned the
docs were useless. It fails soft, with no error and no failed unit, so nobody finds it on purpose.
Now: `.output()`, and four failure modes that stay distinguishable because they need different
fixes — helper not installed, pkexec could not run it, polkit denied it (pkexec's own 126/127), and
the helper ran and refused, whose stderr rides through VERBATIM rather than being re-described. Null
stdin too, so a pkexec that decides to prompt gets EOF instead of parking a stream thread on a tty
read.
The same gate gates the `linger` verb, so on a sessionless host an unjoined user fails there first —
carrying the reason there as well, or the misdiagnosis just moves one message earlier.
A new startup preflight says it before a stream is being built rather than during one, gated so it
cannot nag a box that would never attempt a takeover: not root, a display-manager alias exists, a
managed session launcher exists, a packaged helper exists, and the user is not in the group. It reads
membership from the user database rather than this process's groups, deliberately: that is what the
helper reads (it runs as root and resolves the caller from the database), so `usermod -aG` satisfies
the DM gate immediately and the warning stops. Using `getgroups()` would keep warning on a box where
the takeover already works.
Packaging said the group was for "the virtual Steam Deck pad (usbip)" — so anyone without a Deck pad
correctly skipped it and landed here by following instructions properly. All three scriptlets now
lead with Game Mode, name both grants, and record that creating the group is necessary and NOT
sufficient. Docs get the same treatment: the group is an admonition above the DM-flavor list in
gamescope.md, a black-screen entry in troubleshooting.md that tells the reader to read the quoted
reason FIRST, and the per-distro install pages no longer frame it as pad-only.
213 lines
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213 lines
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Markdown
---
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title: Arch Linux
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description: Install a Punktfunk host on Arch (and Arch-derived distros) from the signed pacman binary repo.
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---
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Set up a Punktfunk host on **Arch Linux** (or an Arch-derived distro like CachyOS/EndeavourOS). The
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host installs from a **signed pacman binary repo**, so it updates with `pacman -Syu` like the rest
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of your system — no building required. Host encode is **NVENC on NVIDIA**; on **AMD/Intel** HEVC
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and AV1 go through **Vulkan Video**, with **VAAPI** for H.264 and as the fallback
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(`PUNKTFUNK_ENCODER=auto` picks per GPU).
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> New here? Read [Security & Safe Use](/docs/security) first — a streaming host is remote control of
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> the machine, so keep it on a trusted LAN or VPN and require pairing.
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> Prefer to build it yourself? A split `PKGBUILD` (host + client + optional web console) is in the
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> repo at `packaging/arch/` — see the [appendix](#appendix--build-from-source-pkgbuild). The binary
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> repo below is the supported path.
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## 1. GPU prerequisites
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- **NVIDIA:** `sudo pacman -S --needed nvidia-utils` (provides NVENC + the EGL/CUDA zero-copy path).
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Arch's stock `ffmpeg` already has NVENC built in — no RPM-Fusion-style swap like Fedora needs.
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- **AMD / Intel:** the Mesa stack. HEVC/AV1 encode goes through **Vulkan Video** by default, so
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install the Vulkan driver — `vulkan-radeon` (AMD) or `vulkan-intel` (Intel) — alongside the VAAPI
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drivers (`libva-mesa-driver` for AMD, `intel-media-driver` for Intel), which carry H.264 and the
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fallback path. Both are usually already installed on a desktop.
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## 2. Add the signed repo
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The registry **signs its database and every package**, so first trust its key once (after this,
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packages install signature-verified):
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```sh
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# Trust the registry signing key.
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curl -fsS https://git.unom.io/api/packages/unom/arch/repository.key \
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| sudo pacman-key --add -
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sudo pacman-key --lsign-key E0CA04465C99C936E0B0C6510A317015A34DDD69
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# Add the repo (append to /etc/pacman.conf). No SigLevel line needed — pacman's default
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# verifies signed packages against the key you just trusted. (printf, not a heredoc, so this
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# works in fish too — CachyOS's default shell has no `<<EOF` support.)
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printf '\n[punktfunk]\nServer = https://git.unom.io/api/packages/unom/arch/$repo/$arch\n' \
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| sudo tee -a /etc/pacman.conf >/dev/null
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```
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> **Stable vs canary.** `[punktfunk]` is the **stable** channel — it moves only when a `vX.Y.Z`
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> release is cut. For the latest `main` build, use `[punktfunk-canary]` instead (same `Server` line,
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> just the repo name). Enable exactly one. See [Release Channels](/docs/channels).
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## 3. Install the host
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```sh
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sudo pacman -Syu punktfunk-host # the streaming host
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sudo pacman -Syu punktfunk-web # optional: the browser management console (pairing + status)
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sudo pacman -Syu punktfunk-gamescope # optional: HDR (10-bit BT.2020 PQ) off gamescope sessions
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sudo pacman -Syu punktfunk-scripting # optional: the plugin/script runner (see below)
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sudo usermod -aG input "$USER" # /dev/uinput access for virtual gamepads (re-login to apply)
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```
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Also join `punktfunk` if **either** applies — you want the **virtual Steam Deck controller**
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(paddles, trackpads, gyro — it reaches games as a real USB pad, which is why Steam Input adopts
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it), or this box autologins into Steam **Gaming Mode** and you want the host to take that session
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over at the client's resolution:
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```sh
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sudo usermod -aG punktfunk "$USER" # usbip/vhci + display-manager takeover (re-login to apply)
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```
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That is a second group on purpose. It grants write access to the usbip `attach` file, which
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materialises an arbitrary emulated USB device — so it stays off the `input` group everyone is
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routinely told to join. Join it only on a machine you trust. On a plain desktop host, everything
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else still works without it and the pad simply arrives as an ordinary Xbox 360 controller; on a
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Gaming Mode box the takeover silently degrades to mirroring the box's own screen — see
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[gamescope](/docs/gamescope#nobara-and-other-autologin-display-managers).
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Each install is a **full** `-Syu`, on purpose: our packages are built against current Arch
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sonames, and `pacman -Sy <pkg>` would drop one onto a system whose other packages are still old —
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the classic partial upgrade that breaks Arch boxes. To take several in one go, name them on a
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single line: `sudo pacman -Syu punktfunk-host punktfunk-web punktfunk-gamescope`.
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`punktfunk-scripting` is the runner behind [Plugins](/docs/plugins); it isn't started for you —
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`systemctl --user enable --now punktfunk-scripting` when you want it. `punktfunk-client` (the native
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GTK4 Linux client) is in the same repo if this box is also a client. The host package ships the
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systemd **user** units, the udev rule, the UDP socket-buffer sysctl tuning, and example configs.
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Updates later are a normal `sudo pacman -Syu`, then `systemctl --user restart punktfunk-host` so the
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running host picks up the new binary. A `-Syu` moves every Punktfunk package you installed, so
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restart `punktfunk-web` the same way if you run the console. The web console can run the update for
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you — see [Updating the Host](/docs/updating); on Arch that button additionally needs
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`PACMAN_FULL_SYSUPGRADE=1` in `/etc/punktfunk/update.conf`, because the only pacman update we will
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run is a full one.
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## 4. Configure and run
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The host runs as a systemd **`--user`** service — it needs your session's PipeWire and D-Bus. Copy a
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starting config:
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```sh
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mkdir -p ~/.config/punktfunk
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cp /usr/share/punktfunk/host.env.example ~/.config/punktfunk/host.env
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```
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How the host creates its virtual display and injects input depends on your desktop, not your distro —
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edit `host.env` for the desktop you run, following its page for the exact settings and any quirks:
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- [KDE Plasma (KWin)](/docs/kde)
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- [GNOME (Mutter)](/docs/gnome)
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- [Steam / gamescope](/docs/gamescope)
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- [Hyprland](/docs/hyprland)
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- [Sway / wlroots](/docs/sway)
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Then enable the service and turn on linger so it starts at boot without a login:
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```sh
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systemctl --user daemon-reload
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systemctl --user enable --now punktfunk-host
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sudo loginctl enable-linger "$USER"
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```
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Check it came up:
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```sh
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systemctl --user status punktfunk-host # active
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journalctl --user -u punktfunk-host -f # watch a client connect
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```
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Enable the browser console, find your login password, and arm PIN pairing from
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[The Web Console](/docs/web-console). For a headless KWin appliance that streams at boot with no
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graphical login, see [KDE → Headless session](/docs/kde#headless-session). Full reference:
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[Configuration](/docs/configuration) · [Running as a Service](/docs/running-as-a-service).
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## 5. Open the firewall (if you have one)
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**Stock Arch ships no firewall** — every port is already open, so you can skip this. But **CachyOS
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enables `ufw` by default** (firewalld is not installed), and some other spins (e.g. EndeavourOS)
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enable **`firewalld`** — an Arch package never opens ports for you, so on those the host is
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unreachable until you allow it.
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The `punktfunk-host` package installs openers for **both**, so it's a one-liner whichever you run.
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The unit you enabled in step 4 runs `serve --gamestream` — the package installs it as it ships and
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only rewrites the binary path — so that host serves **both** the native `punktfunk/1` plane and
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stock [Moonlight](/docs/moonlight) clients, and needs **both** openers:
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```sh
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# ufw — CachyOS (and Ubuntu, once you enable ufw):
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sudo ufw allow punktfunk-native
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sudo ufw allow punktfunk-gamestream
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# firewalld — Fedora-like spins (EndeavourOS, …):
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sudo firewall-cmd --reload # load the installed definitions
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sudo firewall-cmd --permanent --add-service=punktfunk-native
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sudo firewall-cmd --permanent --add-service=punktfunk-gamestream
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sudo firewall-cmd --reload
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```
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Switched the host to **native-only** — dropped `--gamestream` with a
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`systemctl --user edit punktfunk-host` drop-in, or you run `punktfunk-host serve` by hand? Then open
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`punktfunk-native` alone and leave `punktfunk-gamestream` closed. `systemctl --user cat
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punktfunk-host` shows which one yours is.
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`punktfunk-native` opens the QUIC control port (UDP 9777), mDNS discovery and the mgmt/library API
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(TCP 47990); `punktfunk-gamestream` opens the fixed Moonlight ports — TCP 47984, 47989 and 48010,
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UDP 47998–48000 — plus the same mDNS.
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The media **data plane** uses an *ephemeral* UDP port that the client opens with a hole-punch — the
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host streams back out through the path the client opened, so there's **nothing fixed to open** as
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long as the firewall allows outbound UDP (the default for both ufw and firewalld).
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Enabled the **web console** (`punktfunk-web`, above) and want to reach it from your phone or another
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machine? It's not opened by the streaming rules — open its port too, the same one-liner way:
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```sh
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sudo ufw allow punktfunk-web # ufw
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sudo firewall-cmd --permanent --add-service=punktfunk-web && sudo firewall-cmd --reload # firewalld
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```
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That opens **TCP 47992** (HTTPS, login-gated). The mgmt API (47990) is opened for paired clients by the
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`punktfunk-native` profile (game-library browsing over mTLS); off-loopback it serves only read-only
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status/library, and every admin action stays loopback-only. Full port lists (`nftables`, explicit ports) are in
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[`packaging/arch/README.md`](https://git.unom.io/unom/punktfunk/src/branch/main/packaging/arch/README.md#firewall).
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## 6. Connect a client
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From any [client](/docs/clients), `--discover` finds the host on the LAN. On first connect, complete
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the **PIN pairing**: arm it from [The Web Console](/docs/web-console#arm-pairing), which displays a
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4-digit PIN to type into the client. (Pairing is required by default; pass `serve --open` only if
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you deliberately want to disable it.) See [Clients](/docs/clients) for per-platform setup.
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## Next steps
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- **Keep it current** — [Updating the Host](/docs/updating).
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- **Remove it again** — [Uninstalling](/docs/uninstall).
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- **Something not working?** — [Troubleshooting](/docs/troubleshooting).
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## Appendix — build from source (PKGBUILD)
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To build instead of using the binary repo, use the split `PKGBUILD` in `packaging/arch/` (produces
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`punktfunk-host` + `punktfunk-client`; set `PF_WITH_WEB=1` to also build `punktfunk-web` and
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`PF_WITH_SCRIPTING=1` to also build `punktfunk-scripting` — both need `bun`):
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```sh
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git clone https://git.unom.io/unom/punktfunk.git && cd punktfunk/packaging/arch
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# Build the working tree (no git fetch):
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PF_SRCDIR="$(git rev-parse --show-toplevel)" makepkg -f --holdver
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sudo pacman -U punktfunk-host-*.pkg.tar.zst
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```
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NVENC/EGL come from the NVIDIA driver (`nvidia-utils`); on a GPU-less builder, symlink the CUDA
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stub into the link path first (the `PKGBUILD` header documents this). Full details, the
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Fedora→Arch dependency map, and the systemd-sysext mechanism are in
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[`packaging/arch/README.md`](https://git.unom.io/unom/punktfunk/src/branch/main/packaging/arch/README.md).
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(For a **SteamOS host**, use the [on-device installer](/docs/steamos-host) instead — it builds
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the host and the HDR gamescope against the running OS.)
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