linux-kernel - Re: [PATCHv2] at91: fix enable/disable_irq

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Date:	Thu, 10 May 2007 23:01:56 -0700
From:	David Brownell <david-b@...bell.net>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Marc Pignat <marc.pignat@...s.ch>, andrew@...people.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2] at91: fix enable/disable_irq_wake symmetry in pcmcia driver

On Thursday 10 May 2007, Andrew Morton wrote:

> "disable_irq_wake call must be symmetric with enable_irq_wake".  hmm, OK,
> I'll take your word for it.

In the same way that enable_irq() and disable_irq() must be matched,
and for the same reasons:  when the IRQ is shared between drivers,
they can't all treat enable/disable status as boolean.  Those calls
mask refcountig.

> Does the present code actually fail in some manner, or what?

Yes ... runtime warnings flagging various misbehaviors associated
with refcount mismatches.

- Dave

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