udev question

Roel Neefs geryon at gaosu.rave.org
Mon May 24 20:34:49 PDT 2004

On Tuesday 25 May 2004 05:23, Jeremy Utley wrote:
> Bruce Dubbs wrote:
> > Jeremy Utley wrote:
> >> Bruce Dubbs wrote:
> >>> I have not been one of the early adopters of udev and am trying
> >>> to get my arms around the technical details.  To do this, I took
> >>> a look at LFS 6.0.  What is not obvious to me is why udev is in
> >>> Chapter 5. What packages in Chapter 6 require udev to be compiled
> >>> in Chapter 5?  Would it be possible to just do udev once in
> >>> Chapter 6 if the order of packages was changed?
> >>
> >> Udev is in chapter 5 so we can use it to propogate the dev
> >> directory in chroot in chapter 6 once we chroot.
> >
> > Does that mean that the host system has to have udev already
> > installed? -- Bruce
> Nope.  It just needs to be running at least a 2.6.2 kernel, so we can
> mount the sysfs filesystem.  We build udev into /tools, and use that
> from inside chroot to create our /dev directory in chroot.  The only
> requirement on the host is the presence of 2.6.2, because not all
> devices were in sysfs prior to that point.

The host requirement can also be dropped back to the level needed for 
nptl, being 2.5.42 or something like that. If we use the mount --bind, 
we don't need udev interacting with the host kernel, the first time it 
will work is when we reboot in the new and shiny lfs, and then it 
certainly has the recent enough kernel.

> -J-

Roel Neefs
http://lfs.rave.org/lfs/news.html and ftp://gaosu.rave.org/pub/linux/lfs

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