linux-kernel - Re: [PATCH] genirq: Clarify that irq wake state is orthogonal to enable/disable

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Date:   Wed, 05 Feb 2020 12:27:06 +0000
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     linux-kernel@...r.kernel.org, Marc Zyngier <maz@...nel.org>,
        Douglas Anderson <dianders@...omium.org>,
        Lina Iyer <ilina@...eaurora.org>,
        Maulik Shah <mkshah@...eaurora.org>
Subject: Re: [PATCH] genirq: Clarify that irq wake state is orthogonal to enable/disable

Stephen Boyd <swboyd@...omium.org> writes:
> There's some confusion around if an irq that's disabled with
> disable_irq() can still wake the system from sleep states such as
> "suspend to RAM". Let's clarify this in the kernel documentation for
> irq_set_irq_wake() so that it's clear that an irq can be disabled and
> still wake the system if it has been marked for wakeup.
>
> Cc: Marc Zyngier <maz@...nel.org>
> Cc: Douglas Anderson <dianders@...omium.org>
> Cc: Lina Iyer <ilina@...eaurora.org>
> Cc: Maulik Shah <mkshah@...eaurora.org>
> Signed-off-by: Stephen Boyd <swboyd@...omium.org>
> ---
>  kernel/irq/manage.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 818b2802d3e7..fa8db98c8699 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -731,6 +731,11 @@ static int set_irq_wake_real(unsigned int irq, unsigned int on)
>   *
>   *	Wakeup mode lets this IRQ wake the system from sleep
>   *	states like "suspend to RAM".
> + *
> + *	Note: irq enable/disable state is completely orthogonal
> + *	to the enable/disable state of irq wake. An irq can be
> + *	disabled with disable_irq() and still wake the system as
> + *	long as the irq has wake enabled.

It clearly should say that this is really depending on the hardware
implementation of the particual interrupt chip whether disabled + wake
mode is supported.

Thanks,

        tglx