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From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Alek Du <alek.du@intel.com>
Cc: "ext-phil.2.carmody@nokia.com" <ext-phil.2.carmody@nokia.com>,
	"Nikula Jani.1 (EXT-Nixu/Helsinki)" <ext-jani.1.nikula@nokia.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Trilok Soni <soni.trilok@gmail.com>,
	"linux-input@vger.kernel.org" <linux-input@vger.kernel.org>,
	"ben-linux@fluff.org" <ben-linux@fluff.org>
Subject: Re: [PATCH]input: Change timer function to workqueue for gpio_keys driver
Date: Thu, 25 Jun 2009 09:42:42 -0700	[thread overview]
Message-ID: <d120d5000906250942j1d25f4d6rccc12034758f8815@mail.gmail.com> (raw)
In-Reply-To: <20090626002345.07928230@dxy.sh.intel.com>

On Thu, Jun 25, 2009 at 9:23 AM, Alek Du<alek.du@intel.com> wrote:
> On Fri, 26 Jun 2009 00:09:14 +0800
> Phil Carmody <ext-phil.2.carmody@nokia.com> wrote:
>
>> If you stopped calling the delay after the first transition "debouncing
>> time" and simply called it a "delay" you might more easily see that it
>> does *no* debouncing at all. Imagine putting noise on the line
>> constantly - the original code's timer would never expire. Your timer
>> will expire after a delay, and while the line is still toggling
>> frantically - you've not debounced.
>
> I don't know if it is really meaningful if you want to handle such pool signal...
> Ok, if you want to handle this ultimate case, will this patch work?
>
>        BUG_ON(irq != gpio_to_irq(button->gpio));
>
> +       cancel_delayed_work_sync(&bdata->work);

Can't do *_sync in interrupt context.

>        delay = button->debounce_interval ?
>                        msecs_to_jiffies(button->debounce_interval) : 0;
>        schedule_delayed_work(&bdata->work, delay);
>

-- 
Dmitry
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  reply	other threads:[~2009-06-25 16:42 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-08  7:24 [PATCH]input: Change timer function to workqueue for gpio_keys driver Alek Du
2009-06-12 17:40 ` Trilok Soni
2009-06-25 10:29   ` Jani Nikula
2009-06-25 13:06     ` Alek Du
2009-06-25 13:31       ` Jani Nikula
2009-06-25 14:08         ` Alek Du
2009-06-25 14:52           ` Jani Nikula
2009-06-25 15:05             ` Jani Nikula
2009-06-25 15:09               ` Alek Du
2009-06-25 15:42                 ` Jani Nikula
2009-06-25 15:48                   ` Alek Du
2009-06-25 16:09                     ` Phil Carmody
2009-06-25 16:23                       ` Alek Du
2009-06-25 16:42                         ` Dmitry Torokhov [this message]
2009-06-26 12:15                         ` [PATCH 0/2] fix gpio-keys debouncing and timer sleep issues Jani Nikula
2009-06-26 12:15                           ` [PATCH 1/2] Revert "Input: gpio-keys - change timer to workqueue" Jani Nikula
2009-06-26 12:15                             ` [PATCH 2/2] input: gpio-keys: avoid possibility of sleeping in timer function Jani Nikula
2009-06-29 10:30                               ` Alek Du
2009-06-26 12:50                           ` [PATCH 0/2] fix gpio-keys debouncing and timer sleep issues Du, Alek
2009-06-29  5:59                           ` Dmitry Torokhov
2009-06-29 10:32                             ` Jani Nikula
     [not found] <20090608135410.1cdbb581@dxy.sh.intel.com>
2009-06-08  6:04 ` [PATCH] input: Change timer function to workqueue for gpio_keys driver Trilok Soni

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