Re: Need help to get udev/hotplug working for extra module

[Greg KH <greg@kroah.com>]

On Thu, Jul 17, 2008 at 11:24:31AM +0200, Holland, John wrote:
> 
> > > > Hi,
> > > >
> > > > nobody here who can give me a hint? Should I ask this on the kernel
> > > > mailing list instead?
> > >
> > > Probably no one really cares about such old and unmaintained systems
> > > anymore, sorry.
> >
> > That's not necessarily true. Many embedded systems continue to use older
> > kernels, even for new development. The devices with which I'm continually
> > confronted, use kernels 2.6.1[23] the newest of which is 2.6.19.
> >
> > And that's their own fault, the kernel community has long had the
> > opinion that this is not a good thing to do.
> >
> I agree, new development should be made with new kernels. But that's
> not always economical. And being linux is becoming more main stream
> and that some embedded devices have a long life cycle it may be
> advantageous to be little more accommodating.

The longer that Linux has been around, the larger the ammount of old
code we would have to support, right?  Where is the fair cut-off point
for the community to support their old releases for free?

It's a tough issue, but usually it only affects the last realease or so,
not stuff 3-5 years ago.

And again, this is a distro specific issue, dealing with how that distro
set up udev and hotplug at the time.  Odds are no one here even was
involved in that (I sure wasn't).

> > If you are using such a kernel, then you need to rely on the support
> > from your vendor, the community can't help you out, sorry.
> At one point in time that kernel was current.
> Is there a time line describing the correlation of kernel version
> to udev version(s)?

A loose one can be found in the Documentation/Changes file, listing the
minimum required version of udev for the kernel.

But again, that's not the issue here.

> When does support for a given udev version expire?

Same as any open source project, when a new release happens or so.

> Where can I find recent udev documentation?

In the udev source code tree.

> > > You may want to check out mdev of a recent busybox version.
> >
> > I don't see how that is relevant to the issue addressed here.  mdev is
> > just what udev was 2-3 years ago, nothing more.
> The mdev's scanning algorithm is much easier to manipulate than that
> of udev.

That's an odd term, given that there is no "scanning algorithm" in udev
at all, we rely on the kernel to provide the events and act apon them,
that's the whole point of the model.

thanks,

greg k-h