RE : RE : Error while opennig device file

Hi everybody! I'm gonna give you all the info you asked me:

[Dustin]

quoted

does it work from the command line?  Do both mknod commands work?

--> Yes both mknod seem to work from the command line since they are =
both created
    root@10.16.9.232:~# mknod -m 777 /dev/test1 c 122 1
    root@10.16.9.232:~# mknod -m 777 /dev/test2 c 122 2           =20
That looks good

quoted

When you "ls -l /dev/test{1,2}" , what do you get?=20

--> root@10.16.9.232:~# ls -l /dev/test{1,2}
    crwxrwxrwx    1 root     root     122,   1 Jun 16  2005 /dev/test1
    crwxrwxrwx    1 root     root     122,   2 Jun 16  2005 /dev/test2
That looks good

quoted

What happens when you "cat /dev/test1" ?

--> root@10.16.9.232:~# cat /dev/test1
    cat: /dev/test1: No such device
That is ok, isn't it?

quoted

What happens when you "echo > /dev/test1" ?   =20

--> root@10.16.9.232:~# echo > /dev/test1
    bash: /dev/test1: No such device
That is ok, isn't it?

[Eugene]

quoted

How does open routine for your device look like?

-->
static int test_open(struct inode *inode , struct file *file)
{
  int ret_val =3D 0;
 =20
  if (Device_open !=3D 0)
    return -EBUSY;
 =20
  Device_open++;
  printk("%d minor number!\n",MINOR(inode->i_rdev)); =20
  MOD_INC_USE_COUNT;

  return ret_val;
}

Very traditionnal...

quoted

What error do you get on second open?

--> I trace the execution of my programm and get the following :
First opened succeeded, open() return code : 3    =20
Can't open second file, open() return code : -1 , errno =3D 16

Looking in the errno.h, we have :
#define	EBUSY		16	/* Device or resource busy */


If tou need more tell me.
Tks again for your help guys!


-------- Message d'origine--------
De: Dustin Lang [mailto:dalang@cs.ubc.ca]
Date: mer. 15/06/2005 20:16
=C0: Eugene Surovegin
Cc: Garcia J=E9r=E9mie; linuxppc-dev@ozlabs.org
Objet : Re: RE : Error while opennig device file
=20

Also - does it work from the command line?  Do both mknod commands work? =

When you "ls -l /dev/test{1,2}" , what do you get?  What happens when =
you=20
"cat /dev/test1" or "echo > /dev/test1" ?

Cheers,
dstn.

quoted

I'm sorry but this is a "copy to mail" error.
Here is the right code:

ret_val =3D system("mknod -m 777 /dev/test1 c 122 1");
ret_val =3D system("mknod -m 777 /dev/test2 c 122 2");

file_desc1 =3D open("/dev/test1", O_RDWR);
file_desc2 =3D open("/dev/test2", O_RDWR);

On Thursday 16 of June 2005 10:35, Garcia J=E9r=E9mie wrote:

static int test_open(struct inode *inode , struct file *file)
{
  int ret_val =3D 0;

  if (Device_open !=3D 0)   <------
    return -EBUSY;           <------

  Device_open++;          <------
  printk("%d minor number!\n",MINOR(inode->i_rdev));
  MOD_INC_USE_COUNT;

  return ret_val;
}

Very traditionnal...

Have a look on marked lines.

 What error do you get on second open?
--> I trace the execution of my programm and get the following :
First opened succeeded, open() return code : 3 =A0 =A0
Can't open second file, open() return code : -1 , errno =3D 16

Looking in the errno.h, we have :
#define=A0EBUSY=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A016=A0=A0=A0=A0=A0=A0/* De=

vice or resource busy */

This is what I would expect. You can remove marked lines and try again...

Regards,
Marcin