linux-kernel - Re: [RESEND] input: keyboard: imx: make sure keyboard can always wake up system

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Message-ID: <20190521053047.GG183429@dtor-ws>
Date:   Mon, 20 May 2019 22:30:47 -0700
From:   "dmitry.torokhov@...il.com" <dmitry.torokhov@...il.com>
To:     Anson Huang <anson.huang@....com>
Cc:     "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>
Subject: Re: [RESEND] input: keyboard: imx: make sure keyboard can always
 wake up system

Hi Anson,
On Thu, Apr 04, 2019 at 01:40:16AM +0000, Anson Huang wrote:
> There are several scenarios that keyboard can NOT wake up system
> from suspend, e.g., if a keyboard is depressed between system
> device suspend phase and device noirq suspend phase, the keyboard
> ISR will be called and both keyboard depress and release interrupts
> will be disabled, then keyboard will no longer be able to wake up
> system. Another scenario would be, if a keyboard is kept depressed,
> and then system goes into suspend, the expected behavior would be
> when keyboard is released, system will be waked up, but current
> implementation can NOT achieve that, because both depress and release
> interrupts are disabled in ISR, and the event check is still in
> progress.
> 
> To fix these issues, need to make sure keyboard's depress or release
> interrupt is enabled after noirq device suspend phase, this patch
> moves the suspend/resume callback to noirq suspend/resume phase, and
> enable the corresponding interrupt according to current keyboard status.

I believe it is possible for IRQ to be disabled and still  being enabled
as wakeup source. What happens if you call disable_irq() before
disabling the clock?

Thanks.

-- 
Dmitry