Re: request_irq() return value

From: Lukas Jelinek
Date: Thu Jul 27 2006 - 14:14:30 EST


Hello,

> Hello,
>
> I'm looking at the source code of different drivers and wondering about
> request_irq() return value. It is used mostly in 'open' routine of struct
> net_device. If request_irq() fails some drivers return -EAGAIN, some -EBUSY
> and some the return value of request_irq(). Is this intentional? Sample
> drivers code:
>

I think the most suitable value for this case is -EBUSY. The reason is
that this type of failure is usually permanent and unrecoverable. But
other people may have a different opinion and thus they prefer -EAGAIN
(which is intended for temporary failures) or something else.

Lukas


> 8139cp.c:
> static int cp_open (struct net_device *dev) {
> ...
> rc = request_irq(dev->irq, cp_interrupt, SA_SHIRQ, dev->name, dev);
> if (rc)
> goto err_out_hw;
> ...
> err_out_hw:
> ...
> return rc;
> }
>
> 3c359.c:
> static int xl_open(struct net_device *dev){
> ...
> if(request_irq(dev->irq, &xl_interrupt, SA_SHIRQ , "3c359", dev)) {
> return -EAGAIN;
> }
> ...
> }
>
> Besides request_irq() is arch dependent so depending on arch it has different
> set of possible return values. So ... does the return value matter or I
> misunderstood something here?
>
> Regards,
>
> Mariusz
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