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Subject: Re: call request_irq before or after hardware initialization?
From: Arjan van de Ven <arjan@infradead.org>
To: Li Juen Hwang <lwen@ampex.com>
Cc: linux1394-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
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Organization: Intel International BV
Date: Fri, 29 Jun 2007 13:23:07 -0700
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On Fri, 2007-06-29 at 12:35 -0700, Li Juen Hwang wrote:
> 
> Hi,
> 
>     Most 1394 drivers on Linux, ohci1394 for instance, calls 
> request_irq() before
>     initializing/enabling hardware chip. I'd like to reverse the order 
> so that driver
>     can exit the kernel without calling free_irq() if hardware failed. 
> Is that ok?
>     will it cause side effect? Thanks.

well you have to be able to handle interrupts the moment the hardware
will generate them... so the request_irq has to happen before that
point.