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 21:36:21 +0200
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Thomas Gleixner <tglx@...utronix.de>
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

Hi Thomas,

On Tue, Sep 8, 2015 at 9:05 PM, Thomas Gleixner <tglx@...utronix.de> wrote:
> On Tue, 8 Sep 2015, Geert Uytterhoeven wrote:
>> The renesas-intc-irqpin interrupt controller is cascaded to the GIC, but
>> its driver doesn't propagate wake-up settings to the parent interrupt
>> controller.
>>
>> Since commit aec89ef72ba6c944 ("irqchip/gic: Enable SKIP_SET_WAKE and
>> MASK_ON_SUSPEND"), the GIC driver masks interrupts during suspend, and
>> wake-up through gpio-keys now fails on r8a7740/armadillo and
>> sh73a0/kzm9g.
>>
>> Fix this by propagating wake-up settings to the parent interrupt
>> controller. There's no need to handle irq_set_irq_wake() failures, as
>> the renesas-intc-irqpin interrupt controller is always cascaded to a
>> GIC, and the GIC driver always sets SKIP_SET_WAKE since the
>> aforementioned commit.
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
>> ---
>>  drivers/irqchip/irq-renesas-intc-irqpin.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/irqchip/irq-renesas-intc-irqpin.c b/drivers/irqchip/irq-renesas-intc-irqpin.c
>> index 0670ab4e3897bf61..457d22c09e352d56 100644
>> --- 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.

E.g. on sh73a0/kzm9g gpio-keys wake-up goes through 3 interrupt controllers:
pcf875x -> renesas-intc-irqpin -> gic.

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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