Re: Documentation for sysfs, hotplug, and firmware loading.

Greg KH
2007-07-20T08:13:30Z

On Fri, Jul 20, 2007 at 09:54:01AM +0200, Cornelia Huck wrote:
> On Fri, 20 Jul 2007 00:00:01 -0700,
> Greg KH <greg@kroah.com> wrote:
>
> > > I don't insist on it, mknod insists on it. You cannot mknod a dev node
> > > without specifying block or char.
> > >
> > > You're saying that sysfs should provide major and minor numbers without
> > > anywhere specifying "char" or "block", meaning the major and minor numbers
> > > cannot be _used_. I am insisting on getting the third piece of information
> > > without which "major" and "minor" are useless.
> > >
> > > I asked very specifically about this at OLS, several times. What you're
> > > telling me now seems to contradict what you told me then.
> >
> > Here's the rule:
> > If the SUBSYSTEM is "block", it's a block device. Otherwise
> > it's a char device.
>
> That's actually quite confusing to the casual reader, since:
>
> > But also realize that the majority of events you will get have nothing
> > to do with device nodes. I think you are forgetting this fact.
>
> So the rule should be:
> If the SUBSYSTEM is "block" (implying major/minor are provided),
> it's a block device.
> If the SUBSYSTEM is not "block", and major/minor are provided,
> it's a char device.
> If major/minor are not provided, the event/device is not
> relevant to device node creation.

Yes, that is much more descriptive, thanks.

greg k-h