A new kiosk type, hosts/steam-tv-box/, plus tools/build-steam-tv-box-iso.sh.
It boots straight into Steam Big Picture and runs games ON the machine — the
opposite end of hosts/thin-client's Steam Link, which streams a game rendered
somewhere else and needs no graphics performance at all.
Native Steam (steam-installer, contrib) goes in via a hook rather than the
package list: it is unusable until `dpkg --add-architecture i386` has run, and
live-build installs package lists before hooks. With it come the i386 half of
the Mesa/Vulkan/SDL stack (most pre-2015 titles are still 32-bit and fail with
an opaque GL-context error without it), steam-devices' udev rules, gamemode,
mangohud, and gamescope when the release has it.
First host to override household.debian_release. A new optional per-kiosk
`debian_release` key pins this image to trixie; bookworm's Mesa 22.3 is fine
for every other host here — they are a browser and a Python agent — and not
fine for the one machine that renders. It is also the only thing on this box
that cannot be fixed later by editing a config file.
`gpu_vendor` (amd/intel/nvidia) is configuration, not detection, and the
validator requires it: the build host cannot see the target machine, and
installing the NVIDIA driver on an AMD box actively breaks it.
The media apps do not exist until you leave Big Picture. Firefox (uBlock
Origin + SponsorBlock), Spotify and mpv start the first time somebody actually
leaves it — not tidiness, but because this is the one machine here where a
background browser and an open Spotify audio stream turn up as stutter in a
frame-limited title. Two independent triggers, because there are two ways to
leave and neither can see the other: steam-session runs steam-big-picture in
the foreground and continues when the client exits, and session-watcher
subscribes to sway workspace-focus events for "exited Big Picture but Steam is
still running". Both call an idempotent media-session start, guarded per-app by
pgrep and as a whole by flock. Window-title matching was rejected: Steam's
titles and window structure have moved across client rewrites, and a media
session that silently stops appearing after an update reads as a broken image
rather than a moved string.
Going back into a game tears nothing down — people play music over games on
purpose. `media-session stop` exists behind one explicit HA button and nothing
calls it automatically.
Prism Launcher runs through Steam, not beside it. steam-shortcut-prism writes
it into the user's binary shortcuts.vdf as a non-Steam game and prism-launch
starts it via steam://rungameid/, so Minecraft runs inside the Steam Runtime
with Steam Input and the Steam Controller API live. That cannot be baked into
the ISO (userdata/<steamID3>/ does not exist until somebody logs into Steam,
and no Steam credentials go into an image), so it runs per-session and before
Steam starts — Steam rewrites that file from memory on exit. It falls back to a
direct launch when Steam is absent, and refuses to rewrite a shortcuts.vdf that
already holds other entries rather than risk eating them.
steamtv-agent adds one genuinely new entity to the kiosk vocabulary: a
session-mode sensor (gaming/steam/media/idle, from two cheap local facts) so HA
can answer "is somebody playing?" without guessing from power draw. The rest —
transport, volume, audio-output select, workspace select, launch buttons, CEC
display switch — is the thin client's surface over the same MQTT-only control
boundary: no HTTP listener, no exposed Sway IPC socket, every handler an
enumerated action, payloads never argv elements.
enable_installer defaults true here, unlike every other kiosk: a live system
keeps its writable layer in RAM and a Steam library would vanish on reboot.
Never built, never flashed, never booted, no hardware chosen. Four things are
reasoned rather than verified and are flagged in the host README and as open
decision #43: the shortcuts.vdf binary format and non-Steam AppID derivation
(Valve documents neither), gamescope's availability in trixie, the two Flathub
app IDs, and the NVIDIA driver package names.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Amir Alexander Abdelbaki
2f42b88c19