enricobuehler
fb309e0262
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.
12 KiB
title, description
| title | description |
|---|---|
| Bazzite | Set up a Punktfunk host on Bazzite — it follows the box between Steam Gaming Mode (gamescope) and the KDE Plasma desktop automatically. |
Bazzite already ships everything a Punktfunk host needs — the NVIDIA driver, NVENC, PipeWire, gamescope, and the KDE Plasma desktop. So a Bazzite host is the most "appliance-like" setup, and it streams both of Bazzite's faces:
- Steam Gaming Mode (gamescope) — the couch/handheld game UI.
- The KDE Plasma desktop — the full desktop you get from "Switch to Desktop".
The host auto-detects which one is live and follows the box across the switch — including
mid-stream. You flip between Gaming Mode and Desktop with Bazzite's normal Steam UI /
"Switch to Desktop"; the host just re-targets whatever's running and keeps streaming. Nothing in
host.env forces a mode.
Ideal for a dedicated game-streaming box that you also occasionally want as a remote desktop. For a pure desktop machine, install on Ubuntu or Fedora and configure the KDE or GNOME desktop directly — simpler.
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.
Install
The host installs as a systemd system extension (sysext) — no rpm-ostree layering. The
Bazzite docs treat layering as a last resort (layered packages slow every OS update and can block
upgrades until removed); a sysext never enters an rpm-ostree transaction: it overlays /usr
read-only from /var/lib/extensions/, survives OS updates, installs and updates without a
reboot, and is removable in one command. This is the same mechanism the Fedora Atomic
maintainers ship via the fedora-sysexts project.
# One-time bootstrap (afterwards the updater is on PATH as `punktfunk-sysext`):
curl -fsSLO https://git.unom.io/unom/punktfunk/raw/branch/main/packaging/bazzite/punktfunk-sysext.sh
sudo bash punktfunk-sysext.sh install # add `--channel canary` for rolling builds
That downloads the newest image — host + tray + web console + the plugin runner
(punktfunk-scripting), plus the HDR punktfunk-gamescope build — merges it, and applies the
udev/sysctl setup on the spot; the host is usable immediately, no reboot. The feed's checksum
manifest is OpenPGP-signed by packages@unom.io (key AF245C506F4E4763, the same one that signs our
RPMs), and punktfunk-sysext checks that signature against a key baked into the script before it
trusts a single checksum — so it needs gpg on the box, and it refuses a feed it can't verify.
The plugin runner rides along in the image but isn't started: run
systemctl --user enable --now punktfunk-scripting when you want plugins.
From then on:
sudo punktfunk-sysext update # fetch + merge the newest build
sudo punktfunk-sysext status # channel, installed vs latest version
sudo punktfunk-sysext remove # unmerge and delete the image (~/.config/punktfunk is kept)
After an update, restart the host so it runs the new binary (the updater prints this reminder too). The image carries the console as well, so restart that first if you enabled it:
systemctl --user restart punktfunk-web # only if you run the console
systemctl --user restart punktfunk-host
To switch channel later, re-run the install: sudo punktfunk-sysext install --channel canary
(or --channel stable). update takes no channel flag — it follows whatever the last install wrote
to /etc/punktfunk-sysext.conf. To be able to go back to a build that worked, keep a copy of the
image before you update, and re-install that file afterwards:
sudo cp /var/lib/extensions/punktfunk.raw ~/punktfunk-known-good.raw # before updating
sudo punktfunk-sysext install --from-file ~/punktfunk-known-good.raw # to go back to it
The web console can also run the update for you — see Updating the Host, which
needs the one-time sudo usermod -aG punktfunk-update $USER.
remove deletes the image and the /etc files it seeded (the tray autostart entry, and the
gamescope session drop-in unless you've edited it), but three things it created outside /usr stay
behind. To clear those too — services first, because once the image unmerges their binaries are
gone and the units just keep failing:
systemctl --user disable --now punktfunk-host punktfunk-web
sudo punktfunk-sysext remove
sudo rm -f /etc/modules-load.d/punktfunk.conf /etc/udev/rules.d/60-punktfunk.rules
sudo groupdel punktfunk-update # the (empty) group for web-console updates
Uninstalling has the same walkthrough for the other install methods, and for the clients.
Three things to know:
- After a Bazzite major rebase (Fedora 43 → 44) the old image refuses to load rather than
run against mismatched system libraries — run
sudo punktfunk-sysext updateonce and it fetches the image built for the new base. - Already layering Punktfunk? Install the sysext (it shadows the layered copy immediately),
then drop the layer so it stops slowing your updates:
sudo rpm-ostree uninstall punktfunk punktfunk-web && systemctl reboot. - If it refuses the feed.
refusing to install from an unsigned feedmeans that Fedora major's feed predates signing; it gets sealed on the next publish. To install from it anyway, accepting that the images are unauthenticated, runsudo env PUNKTFUNK_SYSEXT_ALLOW_UNSIGNED=1 bash punktfunk-sysext.sh install. The other message,the feed's SHA256SUMS is NOT signed by packages@unom.io, is not the same thing — don't install; re-download the script and try again.
For a fully baked appliance image there's also a bootc Containerfile that installs the RPMs
from the registry at image-build time — see packaging/bootc/ in the repo. Plain rpm-ostree
layering from the RPM registry keeps working too: add the
repo exactly as on Fedora, with the baseurl group matching your Fedora base, then
sudo rpm-ostree install punktfunk punktfunk-web and reboot. The sysext is still the supported
default. Building from source also works (Bazzite is Fedora Atomic underneath — same steps as
Fedora).
Allow controller input
Gamepad and DualSense input needs your user in the input group. On Bazzite, don't use
usermod — the base is immutable and the group is managed by a recipe. Use:
ujust add-user-to-input-group
Then log out and back in. (A controller that's "detected but does nothing" is almost always this permission, not a client problem.)
Then join punktfunk — usermod is fine here, because unlike input this group is ours and the
sysext creates it on merge:
sudo usermod -aG punktfunk "$USER" # then log out and back in
This box is a Gaming Mode box, so that group is not optional in practice: it authorizes the
helper the host uses to stop the display manager when it takes the Gaming Mode session over at your
client's resolution, and it gates the usbip attach file the virtual Steam Deck controller
(paddles, trackpads, gyro) attaches through. It is a separate group on purpose — writing that file
can materialise arbitrary emulated USB hardware, so it is not folded into the group everyone is
told to join for gamepads. Without it the pad arrives as an ordinary Xbox 360 controller, and the
takeover degrades to mirroring the box's own screen — see
gamescope.
Configure
The RPM ships a Bazzite-tuned config you can copy as your starting point:
mkdir -p ~/.config/punktfunk
cp /usr/share/punktfunk/host.env.bazzite ~/.config/punktfunk/host.env
The template is deliberately minimal — it does not force a compositor, because the host auto-detects Gaming Mode (gamescope) vs Desktop (KWin) on every connect and follows the switch mid-stream. No session anchors are needed either (a user service inherits the right runtime dir). The only settings that matter (GPU zero-copy is on by default):
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_GAMESCOPE_ATTACH=1 # Gaming Mode = attach to the box's own session — SDR, and no cursor (see below)
Gaming Mode: attach vs managed
For Gaming Mode there are two models (pick one; the shipped default is attach):
- Attach (
PUNKTFUNK_GAMESCOPE_ATTACH=1, the template's default) — the box owns its gamescope session on its own display, and the host attaches to whatever's live without ever tearing it down (on a headless box, a box-owned autologin session is restarted at the client's resolution on a mismatch; with a display connected it streams at the box's own mode). Switching Desktop ↔ Game is rock-solid. - Managed (
PUNKTFUNK_GAMESCOPE_MANAGED=1, and remove the attach line) — the host takes the box's gamescope over and relaunches it headless at the client's exact resolution and refresh — Game Mode on the virtual screen — restoring the box on idle.
Full treatment: Steam / gamescope → How the host gets a gamescope.
Mid-stream Gaming ↔ Desktop following (PUNKTFUNK_SESSION_WATCH) is on by default on
Bazzite/SteamOS. See Configuration for the full list of knobs.
Streaming the KDE Plasma desktop
The virtual output (video) for the Desktop session needs no config — the host package ships an
io.unom.Punktfunk.Host.desktop file whose X-KDE-Wayland-Interfaces grants the host KWin's
restricted screencast protocol on a normal interactive Plasma session (background:
KDE Plasma). After a fresh host install, log out and back into the Desktop session
once so KWin re-reads that grant.
The one thing a normal KDE login lacks is the RemoteDesktop grant for headless input injection. Seed it once (as the streaming user, no root) so the host auto-approves instead of popping an un-answerable dialog:
bash /usr/share/punktfunk/bazzite/kde-desktop-setup.sh
Gaming Mode needs none of this — it auto-attaches.
Run as an always-on host
Bazzite hosts are typically headless. Enable the host service and linger so it starts at boot — see Running as a Service. One host service covers both Gaming Mode and the Desktop; it follows whichever the box is in.
systemctl --user enable --now punktfunk-host
systemctl --user enable --now punktfunk-web # web console: pairing + status
sudo loginctl enable-linger "$USER" # start at boot with nobody logged in
Without that last line the --user units don't start until someone logs in — which on a headless box
never happens.
Then open The Web Console for the login password and to arm pairing.
Good to know
These apply to the Gaming Mode (gamescope) path; the KDE Desktop path is unaffected:
- gamescope 3.16.22 or newer is required; 3.16.23 or newer for the Steam overlay. Below 3.16.22 headless capture can deadlock; between the two, capture works but the Steam overlay (Shift+Tab / the Quick Access Menu) is never painted into the captured node. Bazzite's current gamescope is past both; this only bites if you've pinned an old one.
- The template pins attach, and that costs you both the cursor and HDR. The sysext ships the
punktfunk-gamescopebuild, but it only reaches a session the host starts itself — and thehost.envtemplate above setsPUNKTFUNK_GAMESCOPE_ATTACH=1, where the live session is Bazzite's own stock gamescope. Comment that line out and let the managed default take over: you get the compositor-drawn pointer and real HDR. To stay on attach instead, setPUNKTFUNK_GAMESCOPE_HDR=0andPUNKTFUNK_GAMESCOPE_BIN=/usr/bin/gamescope. Why each half breaks: gamescope → Known limits for the cursor, HDR → Linux + gamescope for the failed connect.
Those are the two that bite on Bazzite. The full set — touch, mouse modes, the clipboard — is on gamescope → Known limits.
Then connect a client — Moonlight works great for couch gaming, and the Apple app for Apple TV / iPad. Trouble? See Troubleshooting.