linux-kernel - Re: [PATCH] set_irq_wake: fix return code and wake status tracking

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Message-Id: <200807230900.27563.david-b@pacbell.net>
Date:	Wed, 23 Jul 2008 09:00:27 -0700
From:	David Brownell <david-b@...bell.net>
To:	Uwe Kleine-König <Uwe.Kleine-Koenig@...i.com>
Cc:	linux-kernel@...r.kernel.org,
	David Brownell <dbrownell@...rs.sourceforge.net>,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	Russell King <rmk@....linux.org.uk>,
	Andrew Morton <akpm@...l.org>,
	Linus Torvalds <torvalds@...l.org>
Subject: Re: [PATCH] set_irq_wake: fix return code and wake status tracking

On Wednesday 23 July 2008, Uwe Kleine-König wrote:
> Since 15a647eba94c3da27ccc666bea72e7cca06b2d19 set_irq_wake returned -ENXIO
> if another device had it already enabled.  Zero is the right value to
> return in this case.  Moreover the change to desc->status was not reverted
> if desc->chip->set_wake returned an error.
> 
> Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@...i.com>
> Cc: David Brownell <dbrownell@...rs.sourceforge.net>

Acked-by: David Brownell <dbrownell@...rs.sourceforge.net>


> Cc: Ingo Molnar <mingo@...e.hu>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Russell King <rmk@....linux.org.uk>
> Cc: Andrew Morton <akpm@...l.org>
> Cc: Linus Torvalds <torvalds@...l.org>
> ---
>  kernel/irq/manage.c |   39 +++++++++++++++++++++++++++------------
>  1 files changed, 27 insertions(+), 12 deletions(-)
> 
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index e01ad8e..227cd49 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -194,6 +194,17 @@ void enable_irq(unsigned int irq)
>  }
>  EXPORT_SYMBOL(enable_irq);
>  
> +int set_irq_wake_real(unsigned int irq, unsigned int on)
> +{
> +	struct irq_desc *desc = irq_desc + irq;
> +	int ret = -ENXIO;
> +
> +	if (desc->chip->set_wake)
> +		ret = desc->chip->set_wake(irq, on);
> +
> +	return ret;
> +}
> +
>  /**
>   *	set_irq_wake - control irq power management wakeup
>   *	@irq:	interrupt to control
> @@ -210,30 +221,34 @@ int set_irq_wake(unsigned int irq, unsigned int on)
>  {
>  	struct irq_desc *desc = irq_desc + irq;
>  	unsigned long flags;
> -	int ret = -ENXIO;
> -	int (*set_wake)(unsigned, unsigned) = desc->chip->set_wake;
> +	int ret = 0;
>  
>  	/* wakeup-capable irqs can be shared between drivers that
>  	 * don't need to have the same sleep mode behaviors.
>  	 */
>  	spin_lock_irqsave(&desc->lock, flags);
>  	if (on) {
> -		if (desc->wake_depth++ == 0)
> -			desc->status |= IRQ_WAKEUP;
> -		else
> -			set_wake = NULL;
> +		if (desc->wake_depth++ == 0) {
> +			ret = set_irq_wake_real(irq, on);
> +			if (ret)
> +				desc->wake_depth = 0;
> +			else
> +				desc->status |= IRQ_WAKEUP;
> +		}
>  	} else {
>  		if (desc->wake_depth == 0) {
>  			printk(KERN_WARNING "Unbalanced IRQ %d "
>  					"wake disable\n", irq);
>  			WARN_ON(1);
> -		} else if (--desc->wake_depth == 0)
> -			desc->status &= ~IRQ_WAKEUP;
> -		else
> -			set_wake = NULL;
> +		} else if (--desc->wake_depth == 0) {
> +			ret = set_irq_wake_real(irq, on);
> +			if (ret)
> +				desc->wake_depth = 1;
> +			else
> +				desc->status &= ~IRQ_WAKEUP;
> +		}
>  	}
> -	if (set_wake)
> -		ret = desc->chip->set_wake(irq, on);
> +
>  	spin_unlock_irqrestore(&desc->lock, flags);
>  	return ret;
>  }
> -- 
> 1.5.6.3
> 


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