linux-kernel - Re: [PATCH] genirq: do not disable IRQ

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Date:	Fri, 12 Jun 2009 11:33:40 -0700
From:	Kevin Hilman <khilman@...prootsystems.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] genirq: do not disable IRQ_WAKEUP marked irqs on suspend

Thomas Gleixner <tglx@...utronix.de> writes:

> On Fri, 12 Jun 2009, Kevin Hilman wrote:
>> Thomas Gleixner <tglx@...utronix.de> writes:
>> 
>> > commit 0a0c5168df (PM: Introduce functions for suspending and resuming
>> > device interrupts) iterates through all interrupts and disables them
>> > on the hardware level. Some architectures have functionality
>> > implemented to mark an interrupt source as wakeup source for suspend,
>> > but the new power management code disables them unconditionally which
>> > breaks the resume on interrupt functionality.
>> >
>> > The wakeup interrupts are marked in the status with the IRQ_WAKEUP
>> > bit. Skip the disablement for those interrupts which have the
>> > IRQ_WAKEUP bit set.
>> >     
>> > Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
>> > Cc: stable@...nel.org
>> 
>> Hi Thomas,
>> 
>> I posted the same patch last month and lost the argument, original
>> thread here:
>> 
>>   http://lkml.org/lkml/2009/5/6/549
>
> Err no. Care to look at the difference ? 

Oops, sent link to wrong patch.  Here's the one solving the same problem:

  http://marc.info/?l=linux-kernel&m=124148347804447&w=2

or

  http://lkml.org/lkml/2009/5/4/448

Only difference is I did the checking outside of the lock, which is
probably wrong.  In any case, you'll be interested in the thread that
follows.

Kevin

> I missed the above discussion, but I'm revisiting the delayed disable
> issue.
>
>> 
>> > diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c
>> > index 638d8be..bce6afd 100644
>> > --- a/kernel/irq/pm.c
>> > +++ b/kernel/irq/pm.c
>> > @@ -29,7 +29,8 @@ void suspend_device_irqs(void)
>> >  		unsigned long flags;
>> >  
>> >  		spin_lock_irqsave(&desc->lock, flags);
>> > -		__disable_irq(desc, irq, true);
>> > +		if (!(desc->status & IRQ_WAKEUP))
>> > +			__disable_irq(desc, irq, true);
>> >  		spin_unlock_irqrestore(&desc->lock, flags);
>> >  	}
>> >  
>> > --
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>> 
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