Camera crashes as I try to add new face for bio recognition

[mimmomarozzi-create]

SUMMARY | 问题概要

On this Deepin system, face enrollment always fails with device is claimed inside the authentication
framework. The root cause is a D-Bus interface incompatibility between deepin-authenticate
(2.0.33, commercial repo) and deepin-face (2.0.16, main repo): the framework expects the new
UOS driver interface (Claim(bool) method, Claimed property, StartEnroll(uuid, faceName),
GetShareMemInfo, ...), while the open-source driver exposes the old interface (Claim property,
EnrollStart(chara, charaType, actionId), anonymous file descriptor). As shipped in the official
repositories, the two components are not compatible with each other.

SOFTWARE/OS VERSIONS | 软件/系统版本信息

| Field | Value |
|---|---|
| OS | Deepin 25 (VERSION_CODENAME=crimson) |
| Kernel | 6.18.48-amd64-desktop-rolling |
| Architecture | amd64 |
| `deepin-authenticate` | 1:2.0.33 (repo `crimson/commercial`) |
| `deepin-face` | 2.0.16 (repo `crimson/main`) |
| Camera | Generic FULL HD 1080P Webcam (USB, ID 2ef4:4255), uvcvideo |
| Runtime | containerized environment (read-only root, persistent home) |

PRE-REQUIREMENT | 预置条件

No response

STEPS TO REPRODUCE | 复现步骤

1. Open Settings → Biometrics → Face → Add face.
2. The webcam LED turns on and immediately turns off; no preview image is shown.
3. Enrollment fails; the framework returns:
   Error org.deepin.dde.DBus.Error.Unnamed: device is claimed
4. org.deepin.dde.Authenticate1.Face.ServiceList stays empty (the driver is never registered).

OBSERVED RESULT | 观察到的结果

4.1 The camera works

• lsusb: 2ef4:4255 Generic FULL HD 1080P Webcam
• /sys/class/video4linux/video0 present, uvcvideo driver loaded.
• Real capture with ffmpeg (YUYV422 and MJPEG, 640x480 → 1920x1080): OK (valid JPEG files).

4.2 The deepin-face driver works when called directly

• EnrollStart as root returns a file descriptor (unix socket): success.
• Claim correctly goes from false to true and back to false after EnrollStop.

4.3 The framework does not register the driver

• Face.ServiceList = "" (empty), FrameworkState = 1 (unavailable).
• CharaManger.DriverInfo = [{"DriverName":"org.deepin.dde.Face1","CharaType":4}]
  (the driver is known but not registered).

4.4 Live D-Bus capture during Face.StartEnroll

error ...: "'face' not exist"
error ...: "Property org.deepin.dde.Face1.Claimed was not found in object /org/deepin/dde/Face1"
error ...: "device is claimed"

After a local binary patch of the driver (Claim→Claimed) the sequence proceeds up to the missing method:

method call sender=:1.480 -> destination=org.deepin.dde.Face1 path=/org/deepin/dde/Face1
           interface=org.deepin.dde.Face1; member=Claim
error "No such method 'Claim' in interface 'org.deepin.dde.Face1' (signature 'b')"

4.5 Driver log (/var/log/deepin-face.log)

QDBusConnection: couldn't handle call to Claim, no slot matched
Could not find slot DbusFaceService::Claim

EXPECTED RESULT | 期望的结果

No response

ADDITIONAL INFORMATION | 额外补充

The framework uses Deepin's go-dbus-factory. The expected driver interface is defined in
go-dbus-factory/system/org.deepin.dde.authenticate1.face/Face.xml
(https://github.com/linuxdeepin/go-dbus-factory/blob/master/system/org.deepin.dde.authenticate1.face/Face.xml):

<interface name="org.deepin.dde.Authenticate1.Face.Device">
    <method name="Claim"><arg name="claimed" type="b" direction="in"/></method>
    <method name="StartEnroll"><arg name="uuid" type="s"/><arg name="faceName" type="s"/></method>
    <method name="StopEnroll"/>
    <method name="GetShareMemInfo">...sockPath, key, size...</method>
    <method name="SetDefaultDevice"/><method name="ListFaces"/><method name="RenameFace"/>...
    <property name="Claimed" type="b" access="read"/>
    <property name="SupportedDevices"/><property name="Capability"/><property name="Status"/>...
</interface>

The actual interface of the installed driver (deepin-face 2.0.16, source:
https://github.com/linuxdeepin/deepin-face/blob/master/dbusfaceservice.h):

Q_PROPERTY(bool Claim READ getClaim)
Q_PROPERTY(QStringList List READ getList)
Q_PROPERTY(qint32 CharaType READ getCharaType)
Q_SLOTS: EnrollStart(chara, charaType, actionId), EnrollStop, VerifyStart, VerifyStop, Delete

Member expected by framework	Driver 2.0.16	Result
Method Claim(bool)	absent (only Claim property)	❌ registration fails
Property Claimed	absent (Claim instead)	❌ (added via local patch)
StartEnroll(uuid, faceName)	EnrollStart(chara, charaType, actionId)	❌ different signature
GetShareMemInfo() → sockPath/key/size	absent (returns anonymous fd)	❌ different frame protocol
SetDefaultDevice/ListFaces/RenameFace/...	absent	❌

The commercial UOS driver (never present in the main repo) implements the new interface;
the open-source deepin-face does not. The official Deepin 25 repositories ship a commercial
framework together with an incompatible open-source driver.

6. Secondary issue (preview)

The camera preview (Qt Multimedia, FFmpeg backend) produces no frames inside the container:
QImage::scaled: Image is a null image in the driver log, LED on/off, while the ffmpeg CLI
captures normally. To be investigated separately (possibly selection of the metadata node
/dev/video1 or format negotiation).

7. Reproduction

1. dbus-send --system --print-reply --dest=org.deepin.dde.Authenticate1 /org/deepin/dde/Authenticate1/Face org.deepin.dde.Authenticate1.Face.StartEnroll string:Domenico string:org.deepin.dde.Face1 string:test
   → Error org.deepin.dde.DBus.Error.Unnamed: device is claimed
2. dbus-send --system --print-reply --dest=org.deepin.dde.Authenticate1 /org/deepin/dde/Authenticate1/Face org.freedesktop.DBus.Properties.Get string:org.deepin.dde.Authenticate1.Face string:ServiceList
   → empty.

8. Proposed fixes (for Deepin)

1. Ship a face driver in the official repos that is compatible with the commercial framework
   (new interface: Claim/Claimed/StartEnroll/GetShareMemInfo), or
2. Downgrade deepin-authenticate to a version compatible with deepin-face 2.0.16, or
3. Document the incompatibility and prevent the cross-installation of these packages.

9. Workarounds applied locally (diagnostic only)

• Binary patch of the driver: property Claim → Claimed (first step of the expected contract).
• Restart=on-failure on the deepin-face service (avoids crash at boot).
• DefaultService=org.deepin.dde.Face1 persisted.
  None of these unblocks enrollment because the missing members cannot be added to a compiled binary.