Re: udev and devfs - The final word

Greg KH
2004-01-07T17:14:22Z

On Tue, Jan 06, 2004 at 02:41:15AM +0100, Andries Brouwer wrote:
> On Mon, Jan 05, 2004 at 04:00:15PM -0800, Greg KH wrote:
>
> > > > Have you even _tried_ udev?
> > >
> > > Yes, and it works reasonably well. I have version 012 here.
> > > Some flaws will be fixed in 013 or so.
> >
> > What flaws would that be? The short time delay for partitions? Or
> > something else?
>
> Yes, partitions are not handled very well.
> So far I have never seen udev discover partitions on its own.

That is because it can not. Please see the current thread "removable
media revalidation - udev vs. devfs or static /dev" on lkml for a
solution to this.

> > > Some difficulties are of a more fundamental type, not so easy to fix.
> >
> > Such as?
>
> Udev cannot do anything when there are no events.
> And media insertion or removal does not always give events.

Exactly. That's why userspace needs to poll for this.

> [By the way, a compilation warning for every C file:
> % make
> gcc -pipe -Wall -Wmore.. -Os -fomit-frame-pointer -D_GNU_SOURCE \
> -I/usr/lib/gcc-lib/i486-suse-linux/3.2/include -I.../udev-012/libsysfs
> -c -o udev.o udev.c
> cc1: warning: changing search order for system directory
> "/usr/lib/gcc-lib/i486-suse-linux/3.2/include"
> cc1: warning: as it has already been specified as a non-system directory]

Odd, it works here just fine on a number of different Red Hat boxes :)

thanks,

greg k-h