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From: Markku Savela <>
Subject: How to get /dev entry created automaticly for dynamic major number?
Date: Thu, 25 Jan 2007 09:35:07 +0200	[thread overview]
Message-ID: <> (raw)

If want to write a loadable module which "implements" a char device
("virtual", no real device present). How do I get the correct
"/dev/foo" to appear automaticly?  What is the current recommended
solution (kernel 2.6.17 in Ubuntu and later).

static int major;

static int __init foo_init(void)
    major = register_chrdev(0, "foo", &fops);

static void __exit foo_exit(void)
    if (major > 0)
        unregister_chrdev(major, "foo");

I thought that the above code would be enough to trigger the "udevd",
but apparently not (if it should, what is the match rule I have to
use? DRIVER=="foo" or KERNEL="foo[0-9]*"? None of these seem to
work). Do I have to do some additional poking with sysfs?  I can see
my module there, but nothing else.

The problem seems to be that most information I find from books or net
is out of date for 2.6, or carries note "these things are currently
been changed". A pointer to a definitive documentation would also do!

             reply	other threads:[~2007-01-25  7:52 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-25  7:35 Markku Savela [this message]
2007-01-25  8:25 ` Greg KH
2007-01-25 13:11   ` Markku Savela
2007-01-25 13:17     ` Markku Savela
2007-01-25 13:37     ` Jiri Kosina
2007-01-25 15:51     ` Greg KH

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