Re: Major number changes after each insmod

On Wed, 01 Dec 2010 11:12:44 +0100, Guillaume Dargaud
<use_the_contact_form@xxxxxxxxxxxxxxxx> wrote:

Hello all,

I'm working on my first 'real' driver for linux (I've done libusb and other
usermode drivers before) and I have some basic questions.

First in the init of the module, I do:
rc = alloc_chrdev_region(&dev,minor,nr_devs,"MyDev");
major=MAJOR(dev);
But the value of dev changes each time I do a new rmmod/insmod: 254, 253,
etc...
So how can match it with mknod ?
mknod /dev/MyDev c 254 0
Right now I need to do it manually each time.
Can't I fix the major number in my driver initialization ?

My load scripts get the major number from /proc/devices. This is left
over from the pre-udev days. I don't know what the official approach
is these days.

http://www.tahomatech.com/downloads/drivers/linux_2.6/pci/x86/files/hardcopy/ihcp_install-2.6

Search for "if [ $1 = load ]" These scripts are pretty clunky -
should make them easier to read :)

Bill
--
William D Waddington
william.waddington@xxxxxxxxxx
"Even bugs...are unexpected signposts on
the long road of creativity..." - Ken Burtch
.

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