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Mikkeli f189a41b02 Correct the camera triage: both Pi 5 connectors take a camera

The first version told the reader a camera in "a DISP port" would never appear.
That is Pi 4 thinking. The Pi 5 has two 4-lane MIPI connectors, CAM/DISP 0 and
CAM/DISP 1, and BOTH are dual-purpose — either one accepts a camera. Left as
written it would have sent someone hunting a port mix-up that cannot happen,
and away from the likelier cause.

Promotes that likelier cause to the top: the Pi 5 uses the narrow 22-pin FPC,
while Pi 4-era camera modules ship with a 15-pin cable and need the adapter.

Also records the evidence that narrows this to hardware rather than config.
pisp_be is loaded and /dev/media0-2 exist, so the imaging pipeline is up, but
/sys/bus/i2c/devices holds only i2c-13 and i2c-14 — no camera bus was
instantiated and no CFE bound. camera_auto_detect probes at boot and loads a
sensor overlay when it finds one, so an absent bus means the firmware found
nothing to probe. Confirmed unchanged across a reboot.

2026-08-05 23:17:47 +09:00

3.5 KiB

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pi5-camera-webui

Camera service for a Raspberry Pi 5: a live video feed served over a small web UI, with face recognition planned as a later stage.

Developed on the machine it runs on (pi5), with Codex as the coding client — see AGENTS.md.

Hardware


Board	Raspberry Pi 5 Model B Rev 1.1
OS	Debian 12 (bookworm), aarch64
Camera	Pi camera module, connected to a CAM port
Host	`pi5`, `192.168.2.154`

⚠ Current state: the camera is NOT detected

Nothing is built yet, and the camera is not visible to the system, so start here:

$ rpicam-hello --list-cameras
No cameras available!

This is a detection problem, not a software one — the userland is already in place:

camera_auto_detect=1 is set in /boot/firmware/config.txt (the correct default; nothing to add)
12 libcamera/rpicam packages are installed
dmesg contains no camera probe lines at all — no sensor (imx*, ov5647), no CFE

That last point is the diagnostic one. A camera that is seen but misconfigured still leaves probe messages; silence means the sensor is not being reached electrically.

The imaging pipeline itself is fine, which narrows it further:

$ lsmod | grep -iE 'pisp|cfe'
pisp_be                49152  0          # ISP backend loaded
$ ls /sys/bus/i2c/devices/
i2c-13  i2c-14                           # no camera i2c bus

camera_auto_detect=1 probes the connectors at boot and loads a sensor overlay when it finds something. No sensor i2c bus was instantiated and no CFE bound, so the firmware found nothing to load an overlay for. Nothing in software will change that.

So check the physical connection, power off first:

The Pi 5 uses the narrower 22-pin FPC connector. Cameras from the Pi 4 era ship with a 15-pin cable, which needs the 22-pin-to-15-pin adapter cable — this is the most common cause of a camera that is connected but invisible.
Ribbon orientation: contacts face the correct side at each end, and the two ends are not the same way round.
The connector latch is fully seated at both ends.
Try the other connector — the Pi 5 has two, CAM/DISP 0 and CAM/DISP 1, and both are dual-purpose, so either accepts a camera. Swapping isolates a faulty port.

Re-check with:

rpicam-hello --list-cameras          # should list a sensor
dmesg | grep -iE 'imx|ov5647|cfe'    # should show a probe
ls /sys/bus/i2c/devices/             # a new bus should appear

⚠ Do not treat /dev/video* as evidence the camera works. Those nodes exist on this Pi already and belong to the video codec and ISP blocks — they are present with no camera attached at all.

picamera2 is not installed yet (import picamera2 fails); it is the expected capture library once a sensor is detected.

Planned stages

Capture — confirm a sensor, grab a still, establish resolution/format.
Live feed — MJPEG stream first (simplest thing that works in a browser); WebRTC later if latency demands it.
Web UI — single page showing the live feed, plus basic controls.
Face recognition — detection first, recognition after; run it on a downscaled frame, not the full stream.

Each stage should be usable on its own before the next begins.

Development

The model endpoint and MCP gateway live on halogen and are reachable from this Pi by name. Codex is installed and configured here; see AGENTS.md for how it is expected to work in this repo.