On Wednesday 11 March 2009, Thomas Gleixner wrote:
> Rafael,
>
> On Wed, 11 Mar 2009, Rafael J. Wysocki wrote:
>
> > Index: linux-2.6/kernel/irq/pm.c
> > ===================================================================
> > --- /dev/null
> > +++ linux-2.6/kernel/irq/pm.c
> > @@ -0,0 +1,89 @@
> > +/*
> > + * linux/kernel/irq/pm.c
> > + *
> > + * Copyright (C) 2009 Rafael J. Wysocki <rjw@xxxxxxx>, Novell Inc.
> > + *
> > + * This file contains power management functions related to interrupts.
> > + */
> > +
> > +#include <linux/irq.h>
> > +#include <linux/module.h>
> > +#include <linux/interrupt.h>
> > +
> > +#include "internals.h"
> > +
> > +/**
> > + * 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;
> > + bool sync = false;
> > +
> > + spin_lock_irqsave(&desc->lock, flags);
> > +
> > + if (desc->action && !(desc->action->flags & IRQF_TIMER)) {
> > + if (!desc->depth++) {
> > + desc->status |= IRQ_DISABLED;
> > + desc->chip->disable(irq);
> > + sync = true;
> > + }
> > + desc->status |= IRQ_SUSPENDED;
>
> This flag needs to be checked in __enable_irq().
>
> > + }
> > +
> > + spin_unlock_irqrestore(&desc->lock, flags);
> > +
> > + if (sync)
> > + synchronize_irq(irq);
> > + }
> > +}
> > +EXPORT_SYMBOL_GPL(suspend_device_irqs);
>
> I'm not too enthusiastic about this open coded implementation of
> disable_irq() with slightly different semantics.
The difference in semantics is important IMO, otherwise I woulndn't have
done that. In particular, IMO, the condition should be under the spinlock IMO
and I'd rather not synchronize all interrupts we don't really disable here.
> Can we please move the fiddling with desc->* into
> kernel/irq/manage.c and share the code there ?
Can you please discuss that with Ingo? I moved that from manage.c at his
request.
Thanks,
Rafael
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