linux-kernel - Re: [PATCH 1/2] irqchip: renesas-intc-irqpin: Propagate wake-up settings to parent

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Date:	Tue, 8 Sep 2015 22:03:41 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>
cc:	Geert Uytterhoeven <geert+renesas@...der.be>,
	Jason Cooper <jason@...edaemon.net>,
	Marc Zyngier <marc.zyngier@....com>,
	Sudeep Holla <sudeep.holla@....com>,
	Magnus Damm <magnus.damm@...il.com>,
	Linux-sh list <linux-sh@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Grygorii Strashko <grygorii.strashko@...com>
Subject: Re: [PATCH 1/2] irqchip: renesas-intc-irqpin: Propagate wake-up
 settings to parent

On Tue, 8 Sep 2015, Geert Uytterhoeven wrote:
> >> --- a/drivers/irqchip/irq-renesas-intc-irqpin.c
> >> +++ b/drivers/irqchip/irq-renesas-intc-irqpin.c
> >> @@ -283,6 +283,9 @@ static int intc_irqpin_irq_set_type(struct irq_data *d, unsigned int type)
> >>  static int intc_irqpin_irq_set_wake(struct irq_data *d, unsigned int on)
> >>  {
> >>       struct intc_irqpin_priv *p = irq_data_get_irq_chip_data(d);
> >> +     int hw_irq = irqd_to_hwirq(d);
> >> +
> >> +     irq_set_irq_wake(p->irq[hw_irq].requested_irq, on);
> >
> > Are you sure that this does not make lockdep unhappy due to lock
> > nesting?
> 
> Actually I did see one lockdep warning, so I'm aware we're probably gonna
> need a similar solution like commit a0a8bcf4670c2c69 ("gpiolib: irqchip:
> use different lockdep class for each gpio irqchip")?
> 
> To be honest, these lockdep warnings aren't helping much here: on embedded
> we typical have several stacked interrupt controllers, so wake-up settings
> have to propagate from the bottom to the top of the stack.

But ignoring them does not help much either, right?
 
> E.g. on sh73a0/kzm9g gpio-keys wake-up goes through 3 interrupt controllers:
> pcf875x -> renesas-intc-irqpin -> gic.

So, yes a seperate locking class for that intc trainwreck is probably
required.

Thanks,

	tglx
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