facing a problem with irq handler,please help me

[Harinderjit Singh Sandhu <harinderjitss@xxxxxxxxx>]

this is the code for the small module that i wrote
------------------------------

----------------------------------

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#define SKELETON_MAJOR 32
#define SKELETON_NAME "skeleton"
#define BASEPORT 0x378
#define PARALLEL_PORT_INTERRUPT 7
#define CASE1 1
#define CASE2 2
static int data;
static unsigned int counter = 0;
static char string [128];
static int data;
//static int interruptcount = 0;

DECLARE_WAIT_QUEUE_HEAD(skeleton_wait);
static int data_not_ready = 1;

// open function - called when the "file" /dev/skeleton is opened in userspace
static int skeleton_open (struct inode *inode, struct file *file) {
    printk("skeleton_open\n");
    // we could do some checking on the flags supplied by "open"
    // i.e. O_NONBLOCK
    // -> set some flag to disable interruptible_sleep_on in skeleton_read
    return 0;
}

// close function - called when the "file" /dev/skeleton is closed in userspace 
static int skeleton_release (struct inode *inode, struct file *file) {
    printk("skeleton_release\n");
    return 0;
}

// read function called when from /dev/skeleton is read
static ssize_t skeleton_read (struct file *file, char *buf,
        size_t count, loff_t *ppos) {
    int len, err;
   
    // check if we have data - if not, sleep
    // wake up in interrupt_handler
    while (data_not_ready) {
        interruptible_sleep_on(&skeleton_wait);
    }
    data_not_ready = 1;
    printk("read works fine");
    if( counter <= 0 )
        return 0;
    err = copy_to_user(buf,string,counter);
    if (err != 0)
        return -EFAULT;
    len  = counter;
    counter = 0;
    return len;
}

// write function called when to /dev/skeleton is written
static ssize_t skeleton_write (struct file *file, const char *buf,
        size_t count, loff_t *ppos) {
    int err;
    printk("write works fine");
    err = copy_from_user(string,buf,count);
    if (err != 0)
        return -EFAULT;
    counter += count;
    return count;
}

// ioctl - I/O control
static int skeleton_ioctl(struct inode *inode, struct file *file,
        unsigned int cmd, unsigned long arg) {
    int retval = 0;
    switch ( cmd ) {
        case CASE1:/* for writing data to arg */
            if (copy_from_user(&data, (int *)arg, sizeof(int)))
            return -EFAULT;
            break;
        case CASE2:/* for reading data from arg */
            if (copy_to_user((int *)arg, &data, sizeof(int)))
            return -EFAULT;
            break;
        default:
            retval = -EINVAL;
    }
    return retval;
}

// interrupt handler
irqreturn_t interrupt_handler (int irqn, void *dev)
{

        printk("Press a key  ");


        return IRQ_HANDLED;


}

// define which file operations are supported
struct file_operations skeleton_fops = {
    .owner    =    THIS_MODULE,
   
    .read        =    skeleton_read,
    .write    =    skeleton_write,
   
    .ioctl    =    skeleton_ioctl,
   
    .open        =    skeleton_open,
   
    .release    =    skeleton_release,
   
};

// initialize module (and interrupt)
static int __init skeleton_init_module (void) {
    int i;

    int ret;
    printk("initializing module\n");
        //free_irq(7,NULL);   
    i = register_chrdev (SKELETON_MAJOR, SKELETON_NAME, &skeleton_fops);
    if (i != 0) return - EIO;
    //disable_irq(7);
    ret = request_irq (7, interrupt_handler,0,SKELETON_NAME ,NULL);
        printk("ret=%d\n",ret);
        //enable_irq(7);
    if(ret>=0){
    enable_irq(7);
//    outb_p(0x10, BASEPORT + 2);
    }
    else
    {
    printk("Not Working \n");
    }
    //printk("Generating interrupt \n");
   
    /*outb(0, BASEPORT);
    outb(255, BASEPORT);
    outb(0, BASEPORT);*/
    printk("Interrupt generated. You should see the handler-message\n");   
   

    return 0;
}

// close and cleanup module
static void __exit skeleton_cleanup_module (void) {
    printk("cleaning up module\n");
    unregister_chrdev (SKELETON_MAJOR, SKELETON_NAME);
    //disable_irq(6);
    //free_irq(6, NULL);
}

module_init(skeleton_init_module);
module_exit(skeleton_cleanup_module);

MODULE_LICENSE("GPL");
----------------------------------------------------------------------------------------


and after insmod ,i get the following error:

- Hide quoted text -

[ 1291.259646] initializing module
> [ 1291.259672] ret=0
> [ 1291.259679] ------------[ cut here ]------------
> [ 1291.259682] WARNING: at
> /build/buildd/linux-2.6.28/

kernel/irq/manage.c:225 __enable_irq+0x30/0x70()
> [ 1291.259685] Unbalanced enable for IRQ 7
> [ 1291.259687] Modules linked in: skeleton(+) hid_bright usbhid rfkill_input
> i915 drm binfmt_misc ppdev bridge stp bnep lp parport arc4 ecb snd_hda_intel
> snd_pcm_oss snd_mixer_oss snd_pcm pcmcia snd_seq_dummy b43 snd_seq_oss
> snd_seq_midi snd_rawmidi mac80211 snd_seq_midi_event cfg80211 iTCO_wdt
> iTCO_vendor_support snd_seq snd_timer snd_seq_device yenta_socket
> rsrc_nonstatic ricoh_mmc sdhci_pci sdhci snd pcmcia_core led_class intel_agp
> agpgart soundcore snd_page_alloc pcspkr input_polldev serio_raw uvcvideo
> compat_ioctl32 videodev v4l1_compat video output ohci1394 ieee1394 8139too
> 8139cp mii ssb fbcon tileblit font bitblit softcursor
> [ 1291.259751] Pid: 4400, comm: insmod Not tainted 2.6.28-11-generic
> #42-Ubuntu
> [ 1291.259754] Call Trace:
> [ 1291.259760]  [<c0139ab0>] warn_slowpath+0x60/0x80
> [ 1291.259765]  [<c0181449>] ? register_handler_proc+0x119/0x130
> [ 1291.259773]  [<c02cc3b8>] ? vsnprintf+0x378/0x5c0
> [ 1291.259778]  [<c013a2f9>] ? release_console_sem+0x1c9/0x200
> [ 1291.259782]  [<c017f570>] __enable_irq+0x30/0x70
> [ 1291.259786]  [<c017f5ec>] enable_irq+0x3c/0x60
> [ 1291.259790]  [<f7f9c000>] ? skeleton_init_module+0x0/0x96 [skeleton]
> [ 1291.259795]  [<f7f9c078>] skeleton_init_module+0x78/0x96 [skeleton]
> [ 1291.259802]  [<c010111e>] _stext+0x2e/0x170
> [ 1291.259807]  [<c020c015>] ? sysfs_addrm_finish+0x15/0xf0
> [ 1291.259811]  [<c020b7e3>] ? sysfs_add_one+0x13/0x50
> [ 1291.259814]  [<c020b85f>] ? sysfs_addrm_start+0x3f/0xa0
> [ 1291.259820]  [<c01a908c>] ? __vunmap+0x9c/0xe0
> [ 1291.259823]  [<c01a908c>] ? __vunmap+0x9c/0xe0
> [ 1291.259832]  [<c01a9121>] ? vfree+0x21/0x30
> [ 1291.259837]  [<c0163f3a>] ? load_module+0x103a/0x1040
> [ 1291.259848]  [<c0163fc8>] sys_init_module+0x88/0x1b0
> [ 1291.259853]  [<c01bb5da>] ? sys_close+0x7a/0xc0
> [ 1291.259857]  [<c0103f6b>] sysenter_do_call+0x12/0x2f
> [ 1291.259865]  [<c0500000>] ? relay_hotcpu_callback+0x6d/0xbd
> [ 1291.259868] ---[ end trace cddcbfa519faa2fe ]---
> [ 1291.259870] Interrupt generated. You should see the handler-message
>
> and the message in the handler doesnt appear.
> i am unable to get what is the problem and how can this be solved.

-- 
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Harinderjit Singh
Sent from Delhi, DL, India