> it requires everyone to rewrite their code if they want to use kdbus rather than doing old-style dbus calls to the compatibility daemon
Umm... the mere existence of the compatibility daemon makes it pretty clear that one could easily build a system which interfaced with kdbus without changing much of your existing code at all. Your code wouldn't have to be that modular to pull it off.
Honestly, the Linux kernel has, for the longest time kind of been filled with these ad-hoc, efficient IPC mechanisms like netlink. It has severely needed SOMETHING like kdbus, and you can see the key pain points in Linux have already been addressed by other systems using their own proprietary or semi-proprietary mechanism (which invariably happens if you are late to a party that people need addressed immediately).
