Re: [PATCH]input: Change timer function to workqueue for gpio_keys driver

Dmitry Torokhov
2009-06-25T16:43:11Z

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