Re: [gentoo-dev] Changing order of default virtual/udev provider

[Alexis Ballier]

On Tue, 16 Feb 2016 20:14:03 +0100
Chí-Thanh Christopher Nguyễn <chithanh@g.o> wrote:

> Alexis Ballier schrieb:
> > I also fail to see how udev using a new linux ipc would make it
> > require systemd. Quoting Lennart:
> > "You need the userspace code to set up the bus and its policy and
> > handle activation. That's not a trivial task. For us, that's what
> > sytemd does in PID 1. You'd need to come up with an alternative for
> > that."
> >
> > If it's just that, it's not limited to udev, but anything using
> > kdbus/bus1, and would mean openrc/${favorite init system} will have
> > to do the same thing anyway. But again, almost 2 years is extremely
> > old considering all the flux that has been around kbus.
>
> OpenRC itself can for now just ignore kdbus, bus1, or whatever kernel
> IPC system comes next.

Well, as Lennart wrote it, kbus would have needed some initialisation.
Just like we have a dbus init script, openrc would have a kdbus one.

> But if upstream udev makes use of the systemd
> userspace interface to the kernel IPC system, then OpenRC would have
> to implement the same interface in order to have working udev.

As I understand it, a kernel IPC doesn't need systemd to work. udev
might use wrappers from libsystemd, or libbus1, just like we have
programs using libv4l or libbluetooth currently.

> Also given the close relationship between systemd and udev, there is
> no guarantee that supporting other users of kdbus/bus1 will make udev
> automagically work. As these two are released together, there is no
> reason to have a stable, public API between them.

Yes, which would mean systemd requires matching udev, not the other way
around. I'm a bit clueless here: Do you have any pointers on the recent
trends on this side ?

Alexis.