Questions about request_irq and reading PCI_INTERRUPT_LINE

["Le Wen" <le_wen@hotmail.com>]

Hi, there,

I have problem to grab video from my ati all-in-wonder card. The card is in 
a PII Celeron machine with an on board video card (ATI Technologies Inc 3D 
Rage IIC AGP). there is no monitor connected with the on board video card. I 
only hook my AIW card with a monitor.

I use km-0.6 from gatos project. I load this km_drv module, but kernel 
always complains:

km: IRQ 0 busy

I checked code:
        km_probe(struct pci_dev *dev, const struct pci_device_id *pci_id)

here dev->irq with a value 0.

When km_probe gets called, it try to request an IRQ0 returns a -EBUSY:
        kms_irq=dev.irq;
        result=request_irq(kms->irq, handler, SA_SHIRQ, tag, (void *)kms);

        if(result==-EBUSY){
                printk(KERN_ERR "km: IRQ %ld busy\n", kms->irq);
                goto fail;
        }


So I tried to get right IRQ number using:
        u8 myirq;
        int rtn=pci_read_config_byte(dev,PCI_INTERRUPT_LINE, &myirq);
        dev->irq=myirq;
        kms->irq=dev_irq;
        result=request_irq(kms->irq, handler, SA_SHIRQ, tag, (void *)kms);

        if(result==-EBUSY){
                printk(KERN_ERR "km: IRQ %ld busy\n", kms->irq);
                goto fail;
        }
        if(result<0){
                printk(KERN_ERR "km: could not install irq handler: 
result=%d\n",result);
                goto fail;
        }
But this time I got:

km: kms->irq=24
km: could not install irq handler: result=-38


My questions are:
1. I don't know why dev->irq has value of 0?

2. Is an IRQ number of 24 valid for a Intel PII Celeron?

3. What does this result=-38 mean?


Wen, Le