linux-kernel - Re: [PATCH 1/3] wm97xx-core: Only schedule interrupt handler if not already scheduled

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Message-ID: <20080415085946.ZZRA012@mailhub.coreip.homeip.net>
Date:	Tue, 15 Apr 2008 09:02:35 -0400
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Jiri Kosina <jkosina@...e.cz>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] wm97xx-core: Only schedule interrupt handler if
	not already scheduled

On Tue, Apr 15, 2008 at 09:48:19AM +0100, Mark Brown wrote:
> On Mon, Apr 14, 2008 at 02:10:02PM -0400, Dmitry Torokhov wrote:
> > On Mon, Apr 14, 2008 at 06:39:33PM +0100, Mark Brown wrote:
> 
> > > +	if (!work_pending(&wm->pen_event_work)) {
> > > +		wm->mach_ops->irq_enable(wm, 0);
> > > +		queue_work(wm->ts_workq, &wm->pen_event_work);
> > > +	}
> 
> > Given the fact that work will not be queued if it is pending anyway
> > why is this change needed?
> 
> As well as not queuing the work it ensures that the calls to
> irq_enable() are balanced which helps with implementing that operation.

Hmm... another question then - what would fire up wm97xx_pen_interrupt()
again, before wm97xx_pen_irq_worker had a chance to run, if the very
first thing we do after getting interrupt is irq_enable(wm, 0)?

-- 
Dmitry
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