Subject: Re: [PATCH] ARM:mfd: fix ezx-pcap build failure

From: Mark Brown <[email-masked]>
Date: Fri, 27 Apr 2012 19:02:35 +0100

On Fri, Apr 27, 2012 at 11:28:28AM -0400, Mark Asselstine wrote:
> On April 26, 2012 22:52:58 Russell King - ARM Linux wrote:

> > What is the effect when the supplied IRQ does not have a mapping to a
> > GPIO - or it _does_ by way of a badly coded irq_to_gpio() function
> > but that GPIO is not the correct one.

> > There is no prevention against endlessly looping, so it could cause a
> > system lockup.

> Unfortunately the commit [b1148fd4 mfd: fix pcap irq bottom handler
> ] which modified things to loop as long as the interrupt is asserted didn't 
> supply much information regarding the behavior they were trying to achieve/fix 
> nor what would be the consequence of bailing earlier.

The usual reason for this pattern is to simulate level triggered IRQs on
an edge triggered interrupt controller.