linux-kernel - Re: [update, rev. 6] Re: [PATCH 1/10] PM: Rework handling of interrupts during suspend-resume (rev. 5)

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Message-Id: <200903132256.51522.rjw@sisk.pl>
Date:	Fri, 13 Mar 2009 22:56:50 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Ingo Molnar <mingo@...e.hu>,
	pm list <linux-pm@...ts.linux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Jeremy Fitzhardinge <jeremy@...p.org>,
	Len Brown <lenb@...nel.org>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Frans Pop <elendil@...net.nl>,
	Arve Hjønnevåg <arve@...roid.com>
Subject: Re: [update, rev. 6] Re: [PATCH 1/10] PM: Rework handling of interrupts during suspend-resume (rev. 5)

On Friday 13 March 2009, Thomas Gleixner wrote:
> On Thu, 12 Mar 2009, Rafael J. Wysocki wrote:
> > +/**
> > + * suspend_device_irqs - disable all currently enabled interrupt lines
> > + *
> > + * During system-wide suspend or hibernation device interrupts need to be
> > + * disabled at the chip level and this function is provided for this purpose.
> > + * It disables all interrupt lines that are enabled at the moment and sets the
> > + * IRQ_SUSPENDED flag for them.
> > + */
> > +void suspend_device_irqs(void)
> > +{
> > +	struct irq_desc *desc;
> > +	int irq;
> > +
> > +	for_each_irq_desc(irq, desc) {
> > +		unsigned long flags;
> > +
> > +		spin_lock_irqsave(&desc->lock, flags);
> > +		__disable_irq(desc, irq, true);
> > +		spin_unlock_irqrestore(&desc->lock, flags);
> 
> Can we move the locking into __disable_irq ?

Well, yes, but (see below)

> > +	}
> > +
> > +	for_each_irq_desc(irq, desc)
> > +		if (desc->status & IRQ_SUSPENDED)
> > +			synchronize_irq(irq);
> > +}
> > +EXPORT_SYMBOL_GPL(suspend_device_irqs);
> > +
> > +/**
> > + * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
> > + *
> > + * Enable all interrupt lines previously disabled by suspend_device_irqs() that
> > + * have the IRQ_SUSPENDED flag set.
> > + */
> > +void resume_device_irqs(void)
> > +{
> > +	struct irq_desc *desc;
> > +	int irq;
> > +
> > +	for_each_irq_desc(irq, desc) {
> > +		unsigned long flags;
> > +
> > +		if (!(desc->status & IRQ_SUSPENDED))
> > +			continue;
> > +
> > +		spin_lock_irqsave(&desc->lock, flags);
> > +		__enable_irq(desc, irq, true);
> > +		spin_unlock_irqrestore(&desc->lock, flags);
> 
> Ditto

No, because of __setup_irq().

Thanks,
Rafael
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