linux-kernel - Re: [PATCH v2] genirq: Clarify that irq wake state is orthogonal to enable/disable

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Message-ID: <20200206195752.GA8107@codeaurora.org>
Date:   Thu, 6 Feb 2020 12:57:52 -0700
From:   Lina Iyer <ilina@...eaurora.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org,
        Marc Zyngier <maz@...nel.org>,
        Douglas Anderson <dianders@...omium.org>,
        Maulik Shah <mkshah@...eaurora.org>
Subject: Re: [PATCH v2] genirq: Clarify that irq wake state is orthogonal to
 enable/disable

On Thu, Feb 06 2020 at 12:15 -0700, Stephen Boyd wrote:
>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.
>
Thomas also mentioned that hardware could work either way and probably
should not be assumed to work one way or the other.

>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>
>---
>
>Changes from v1:
> * Added the last sentence from tglx
>
> kernel/irq/manage.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
>diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
>index 818b2802d3e7..e1e217d7778c 100644
>--- a/kernel/irq/manage.c
>+++ b/kernel/irq/manage.c
>@@ -731,6 +731,13 @@ 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. If this does not hold,
>+ *	then either the underlying irq chip and the related driver
>+ *	need to be investigated.
>  */
> int irq_set_irq_wake(unsigned int irq, unsigned int on)
> {
>-- 
>Sent by a computer, using git, on the internet
>