Hi,
I just saw [1] that comedi is now completely officially in the linux kernels driver, not anymore in the staging area. That's a great news, as it means it should be stay around for a long time. In practice, for us, it also means it'll run really out-of-the-box, without having to disable secure boot (as staging drivers are not allowed to load by default in secure boot mode).
Thanks a lot to every one who helped, and especially Ian!
Éric