mikkeli
fc0836aec7
The car unit has no display of its own (the tablet app is the display), and unified memory is better spent on the voice stack. GDM/GNOME no longer start, a text login stays on tty1, and PulseAudio/PipeWire are disabled for all users while ALSA stays for mic capture. Saves ~200 MB idle; every step is a reversible disable, not a removal. Also notes the pre-existing nightly logrotate failure from the NVIDIA jetson-logging config. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
69 lines
2.9 KiB
Markdown
69 lines
2.9 KiB
Markdown
---
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type: report
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date: 2026-10-09
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---
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# Headless: No Desktop, No Sound Server
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## Why
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The car unit has no display of its own; the display is the tablet app. Anything graphical on the Orin
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uses unified memory, which the voice stack (GPT-SoVITS TTS, Whisper ASR) needs more.
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## Result
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| Item | State |
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|------|-------|
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| Default target | `multi-user.target` (was `graphical.target`): GDM, Xorg and GNOME no longer start |
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| Local console | `getty@tty1` enabled, so a text login appears on a directly attached monitor/keyboard |
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| Sound servers | PulseAudio and PipeWire disabled for all users. **ALSA kept**: devices are still there for mic capture |
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| Camera | `nvargus-daemon` kept (used by `camera-webui` and the later vision service) |
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| Memory | "used" went from 1206 MB to 1005 MB (~200 MB) on an idle system (GDM greeter only, nobody logged in graphically) |
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Per-process RSS for the desktop added up to ~550 MB, but that counts shared pages once per process. The `free` difference is the real saving.
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## Commands
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```
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sudo systemctl set-default multi-user.target
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sudo systemctl enable getty@tty1
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sudo systemctl --global disable pulseaudio.socket pulseaudio.service \
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pipewire.socket pipewire.service pipewire-media-session.service
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sudo systemctl isolate multi-user.target # apply now, without a reboot
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```
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`disable` rather than `mask`: nothing is removed, and each step reverses cleanly.
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```
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sudo systemctl set-default graphical.target
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sudo systemctl --global enable pulseaudio.socket pulseaudio.service \
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pipewire.socket pipewire.service pipewire-media-session.service
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```
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To start the desktop once without changing the default: `sudo systemctl start gdm`.
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## Audio
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Project Yukart's plan keeps the **microphone on the Orin** (Whisper) and sends **TTS to the tablet** as chunked
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utterances. Neither needs a desktop sound server:
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- capture: read the ALSA device directly (`arecord -l` lists it; a USB mic adds its own card);
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- playback on the Orin itself isn't needed (only HDMI is present: `card 0: HDA`).
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If a service later needs PipeWire anyway, run it for that service's user with `loginctl enable-linger <user>`,
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so it starts at boot without a login session. Don't re-enable it globally.
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## Side effects seen when switching live
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`systemctl isolate` re-ran two NVIDIA oneshot units, which then failed because their setup was already done:
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- `nvzramconfig`: `mkswap: /dev/zram5 is mounted`. All six zram swap devices are active, so nothing is missing.
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- `nv_nvsciipc_init`: exits 1 on re-run.
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Both run only once on a normal boot. **To check at the next boot:** `systemctl --failed` should list neither.
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## Unrelated, pre-existing
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`logrotate.service` fails every night: `stat of /data/logging-volume/*.log failed: Permission denied`.
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`/etc/logrotate.d/jetson-logging` (package `nvidia-jetson-services`) rotates as user `logging`, but `/data` is `drwx------ root`.
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Harmless because nothing logs there. Left as is, since it's a package-owned file.
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