Re: [RFC]: add sysfs support to parport_pc, v3

From: Andrew Morton
Date: Wed Jan 04 2006 - 17:32:22 EST


"Jason Dravet" <dravet@xxxxxxxxxxx> wrote:
>
> >From: Greg KH <greg@xxxxxxxxx>
> > > +++ /usr/src/linux-2.6.14/drivers/parport/parport_pc.c 2006-01-01
> > > 11:29:05.000000000 -0600
> >
> >Line wrapped so it can't be applied :(
> >
> > > + * Added sysfs and udev - Jason Dravet <dravet@xxxxxxxxxxx>
> > > */
> >
> >Doesn't belong here, this goes in the change log.
> My mistake.
>
> > > +#include <linux/sysfs.h>
> >
> >Your email client also ate the leading spaces :(
> My email client is hotmail. I have come to realize how much hotmail sucks
> for email. It eats the leading spaces, converts tabs to spaces, and line
> wraps. I will work on getting a new mail account.
>
> > > + class_device_create(parallel_class, NULL, MKDEV(6, countports),
> > > NULL, "lp%i", countports);
> > > + class_device_create(parallel_class, NULL, MKDEV(99, countports),
> > > NULL, "parport%i", countports);
> > > + countports++;
> >
> >What does the 6 and 99 come from? Aren't these #defined in a header file
> >somewhere?
> Good question. The answer is I have no idea. I booted Fedora Core and I
> did a ls -l /dev and wrote down the specs for lp0 and parport0. lp0 looked
> like crw-rw---- root lp 6, 0 date lp0 so that is what I used. After
> reading Linux Device Drivers I found out that 6 is the major number and 0 is
> the minor number. The goal was to make sure that the nodes generated by my
> patch were the same as the nodes generated before my patch so I used those
> numbers. Should I have used different major numbers?
>

6 is OK - it's LP_MAJOR.

However 99 is JSFD_MAJOR, used by drivers/sbus/char/jsflash.c. And yet my
/dev/parport0 is also 99:0 (RH 7.3 and RH FC1). I've no idea how that came
about??

bix:/home/akpm> grep parport /etc/makedev.d/*
/etc/makedev.d/generic:a generic parport
/etc/makedev.d/linux-2.4.x:c $PRINTER 99 0 1 8 parport%d
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