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To: linux-kernel@vger.kernel.org
From: Stephen Hemminger <shemminger@osdl.org>
Subject: Re: request_irq() return value
Date: Thu, 27 Jul 2006 11:13:17 -0700
Organization: OSDL
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References: <200607271950.03370.m.kozlowski@tuxland.pl>
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On Thu, 27 Jul 2006 19:50:03 +0200
Mariusz Kozlowski <m.kozlowski@tuxland.pl> wrote:

> 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:

Correct practice is to propagate the error code of request_irq out to be
the return value of the open routine. This allows the request_irq to return
different values for overlapping irqs, or out of memory, etc.

> 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?

Each architecture should return something sane. If it doesn't then it a problem
that should be addressed there.