linux-kernel - Re: [PATCH 1/2] pinctrl: mediatek: Ignore interrupts that are wake only during resume

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Message-ID: <CACRpkdZd+0_7xqaa05mqNzNxDC1kKmEv9LLRoSVYqTmO=+3iGA@mail.gmail.com>
Date:   Tue, 25 Jun 2019 15:50:50 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Nicolas Boichat <drinkcat@...omium.org>
Cc:     "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        Sean Wang <sean.wang@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Chuanjia Liu <Chuanjia.Liu@...iatek.com>,
        Evan Green <evgreen@...omium.org>,
        Stephen Boyd <swboyd@...omium.org>
Subject: Re: [PATCH 1/2] pinctrl: mediatek: Ignore interrupts that are wake
 only during resume

On Mon, Apr 29, 2019 at 5:55 AM Nicolas Boichat <drinkcat@...omium.org> wrote:

> Before suspending, mtk-eint would set the interrupt mask to the
> one in wake_mask. However, some of these interrupts may not have a
> corresponding interrupt handler, or the interrupt may be disabled.
>
> On resume, the eint irq handler would trigger nevertheless,
> and irq/pm.c:irq_pm_check_wakeup would be called, which would
> try to call irq_disable. However, if the interrupt is not enabled
> (irqd_irq_disabled(&desc->irq_data) is true), the call does nothing,
> and the interrupt is left enabled in the eint driver.
>
> Especially for level-sensitive interrupts, this will lead to an
> interrupt storm on resume.
>
> If we detect that an interrupt is only in wake_mask, but not in
> cur_mask, we can just mask it out immediately (as mtk_eint_resume
> would do anyway at a later stage in the resume sequence, when
> restoring cur_mask).
>
> Fixes: bf22ff45bed ("genirq: Avoid unnecessary low level irq function calls")
> Signed-off-by: Nicolas Boichat <drinkcat@...omium.org>

Patch applied for fixes.
Hm a late ACK made me miss this, sorry.

Yours,
Linus Walleij