linux-kernel - Re: [PATCH] Input: gpio_keys: Make sure wake-up buttons work.

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Date:	Sat, 8 Nov 2014 16:17:08 +1100
From:	NeilBrown <neilb@...e.de>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	GTA04 owners <gta04-owner@...delico.com>
Subject: Re: [PATCH] Input: gpio_keys: Make sure wake-up buttons work.

On Sat, 08 Nov 2014 01:49:06 +0100 "Rafael J. Wysocki" <rjw@...ysocki.net>
wrote:

> On Saturday, November 08, 2014 11:00:58 AM NeilBrown wrote:
> > On Fri, 7 Nov 2014 15:45:07 -0800 Dmitry Torokhov <dmitry.torokhov@...il.com>
> > wrote:
> > 
> > > Hi Neil,
> > > 
> > > On Sat, Nov 08, 2014 at 10:37:07AM +1100, NeilBrown wrote:
> > > > 
> > > > 
> > > > If a key is to be used for wake-up, we must not disable
> > > > the interrupt during suspend.
> > > > 
> > > > Signed-off-by: NeilBrown <neilb@...e.de>
> > > > 
> > > > diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
> > > > index 8c98e97f8e41..0b5e54ae343e 100644
> > > > --- a/drivers/input/keyboard/gpio_keys.c
> > > > +++ b/drivers/input/keyboard/gpio_keys.c
> > > > @@ -526,6 +526,8 @@ static int gpio_keys_setup_key(struct platform_device *pdev,
> > > >  	 */
> > > >  	if (!button->can_disable)
> > > >  		irqflags |= IRQF_SHARED;
> > > > +	if (button->wakeup)
> > > > +		irqflags |= IRQF_NO_SUSPEND;
> > > 
> > > No, enable_irq_wake() should be enough. I believe Rafael has fixed that
> > > in the core, right?
> > > 
> > 
> > Interesting...  you seem to be right, but I was having wakeup problems until
> > I added that patch.
> 
> This was a fairly recent change made in 3.18-rc1.
> 
> > I didn't test exhaustively, but the first time my device entered suspend, the
> > gpio-key didn't wake it up.  Subsequent suspends did...
> > 
> > After I applied this patch, it would reliably wake up even on the first
> > suspend.
> > 
> > So there seems to be something wrong, but maybe it is more subtle.
> > 
> > Is there a good reason why enable_irq_wake() is only called just as the
> > device is being suspended, and why disable_irq_wake() is called on resume?
> > To me it would make more sense to just enable it once (if required) and leave
> > it enabled....
> 
> On some platforms it actually changes the configuration of interrupt
> controllers in to a "suspend mode" which is not appropriate for run time
> AFAICS.
> 
> > I'll see what I can find.
> 
> Yes, please.

Hmmm.. that's frustrating.  I cannot reproduce the problem at all now.  I
wonder what changed..
And I see there are lots of changes in 3.18.

I'll discard my patch and wait to see if the problem recurs.

Thanks for your time,
NeilBrown

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