Files
punktfunk/docs-site/content/docs/bazzite.md
T
enricobuehlerandClaude Fable 5 e35dad529b fix(vdisplay/gamescope): DM-flavor-aware session takeover — stop masking Nobara's plasmalogin to death
Field report (Nobara 43 HTPC): switching the host to Steam Game Mode
mid-stream permanently black-screened the box. Live-proven root cause on
a Nobara repro VM: our takeover masks the box's gamescope-session-plus
unit, plasmalogin's Relogin=true then fails its session Exec repeatedly
and trips systemd's start limit within ~1 s — the display manager dies,
and our restore verb (unmask + user start) cannot bring a seatless
gamescope back. Only 'reset-failed + restart' of the DM recovers.

The takeover is now display-manager-flavor-aware:
- SDDM (Bazzite/SteamOS) keeps the proven mask+SIGKILL path unchanged.
- plasmalogin/unknown DMs never mask: with privilege (root or an
  operator polkit rule scoped to the DM unit — documented) the host
  stops the DM for the stream and restores it with reset-failed +
  restart (PUNKTFUNK_RECOVER_SESSION_CMD as fallback), recorded in the
  persisted takeover state so a host crash still restores; without
  privilege the managed takeover degrades to ATTACH and mirrors the
  box's live Game Mode instead of destabilizing the seat. Both legs of
  the privileged cycle live-verified on the repro VM (headless managed
  session works with zero login sessions; render nodes are 0666).
  A loaded-but-inactive leftover instance never triggers the DM stop.

Companion fixes from the same triage:
- ensure_box_gamescope_mode gains the attach-only rebuild-probe guard
  both managed paths already had (stale post-capture-loss detection
  restarted the box's unit), and no longer re-modes a box that drives a
  physical display — attach mirrors on-glass; re-mode is the
  headless-box model.
- Capture-loss rebuilds targeting gamescope get a 100 s budget: the
  40 s budget expired inside the first 45 s Steam-cold-start launch
  attempt, a guaranteed single-shot failure.
- A PUNKTFUNK_COMPOSITOR pin now WARNs once per capture loss when the
  live session no longer matches it (the pin disables
  session-following — the reporter's original stream-death trigger).
- A managed session that took nothing over (client gamescope pin beside
  a live desktop) is stopped on disconnect instead of being orphaned
  forever.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-24 11:49:24 +02:00

162 lines
7.8 KiB
Markdown

---
title: Bazzite
description: Set up a punktfunk host on Bazzite — it follows the box between Steam Gaming Mode (gamescope) and the KDE Plasma desktop automatically.
---
[Bazzite](https://bazzite.gg/) 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](/docs/ubuntu) or [Fedora](/docs/fedora) and configure the
> [KDE](/docs/kde) or [GNOME](/docs/gnome) desktop directly — simpler.
> New here? Read [Security & Safe Use](/docs/security) 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](https://fedora-sysexts.github.io/) project.
```sh
# 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, SHA-256-verified over HTTPS from
punktfunk's package registry), merges it, and applies the udev/sysctl setup on the spot — the
host is usable immediately, no reboot. From then on:
```sh
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 box is back to stock
```
Two 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 update` once 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`.
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](https://git.unom.io/unom/-/packages) keeps working too (see
`packaging/bazzite/README.md`), but the sysext is the supported default. Building from source
also works (Bazzite is Fedora Atomic underneath — same steps as [Fedora](/docs/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:
```sh
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.)
## Configure
The RPM ships a Bazzite-tuned config you can copy as your starting point:
```sh
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):
```sh
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 (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 → Attach vs managed](/docs/gamescope#attach-vs-managed).
Mid-stream Gaming ↔ Desktop following (`PUNKTFUNK_SESSION_WATCH`) is **on by default** on
Bazzite/SteamOS. See [Configuration](/docs/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](/docs/kde)). 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:
```sh
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](/docs/running-as-a-service). One host service covers both Gaming Mode and the
Desktop; it follows whichever the box is in.
```sh
systemctl --user enable --now punktfunk-host
systemctl --user enable --now punktfunk-web # web console: pairing + status
```
Then open [The Web Console](/docs/web-console) for the login password and to
[arm pairing](/docs/web-console#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.** Older versions can deadlock during capture. Bazzite's
current gamescope is fine; this only bites if you've pinned an old one.
- **The mouse cursor isn't included in the captured image** — a gamescope limitation for now. (The
KDE Desktop path renders the cursor normally.)
- **HDR isn't supported yet** on the gamescope path — gamescope's capture output is 8-bit. SDR streams
normally.
Canonical list: [gamescope → Known limits](/docs/gamescope#known-limits).
Then [connect a client](/docs/clients) — Moonlight works great for couch gaming, and the Apple app for
Apple TV / iPad.