camera_test --highest-device isn't effective at picking the external webcam

I know that for network cards it's possible to edit a file under /udev/rules/ to make sure that they always get the same device.

Maybe is worth to spend some time to investigate if something similar is possible for video devices.

Looks like on my main laptop it puts the external USB camera as /dev/video1 even if inserted at boot time. I'm going to check this is the case again on the other laptop I have.

This seems to be system specific somehow. Perhaps the ordering is done by the model name of the devices, so depending on the name of the built-in camera.

So yeah, we can create udev rules file in the preseed such as:

/etc/udev/rules.d/70-persistent-webcam.rules

and put:

SUBSYSTEM=="video4linux", ENV{ID_MODEL_ID}=="3450", SYMLINK+="external_webcam", ENV{GENERATED}="1"

We may or may not need to expand on the criteria (I think putting 3450 for the model should be good enough. We could also add the manufacturer) but the principle should work.

This would all have to be done in checkbox-satellite, then we would just update the jobs to specify '--device=/dev/external_webcam' instead of '--highest-device'. Alternatively we could leave the jobs as is and set:

KERNEL="video1"

but I haven't tested if this works yet

To be accurate - it should be NAME="video1"

I think the first one could be better as fiddling around with the actual name of the device may affect other tests and it looks clearer to explicitly name the device.