linux-kernel - Re: [Patch 1/1] Input: edt-ft5x06 - disable irq handling during suspend

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Date:   Sat, 22 Jun 2019 13:37:10 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Benoit Parrot <bparrot@...com>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Henrik Rydberg <rydberg@...math.org>,
        Marco Felsch <m.felsch@...gutronix.de>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-input <linux-input@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [Patch 1/1] Input: edt-ft5x06 - disable irq handling during suspend

On Fri, Jun 21, 2019 at 9:53 PM Benoit Parrot <bparrot@...com> wrote:
>
> As a wakeup source when the system is in suspend there is little point
> trying to access a register across the i2c bus as it is probably still
> inactive. We need to prevent the irq handler from being called during
> suspend.
>

Hmm... But how OS will know what the event to handle afterwards?
I mean shouldn't we guarantee somehow the delivery of the event to the
input, in this case, subsystem followed by corresponding user space?

> Without this modification upon wakeup you would see the following kernel
> error:
>
> [ 118.733717] PM: Wakeup source GPIO0
> [ 118.751933] edt_ft5x06 1-0038: Unable to fetch data, error: -13
>
> Signed-off-by: Benoit Parrot <bparrot@...com>
> ---
>  drivers/input/touchscreen/edt-ft5x06.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
> index c639ebce914c..c885bfe783a4 100644
> --- a/drivers/input/touchscreen/edt-ft5x06.c
> +++ b/drivers/input/touchscreen/edt-ft5x06.c
> @@ -1200,8 +1200,10 @@ static int __maybe_unused edt_ft5x06_ts_suspend(struct device *dev)
>  {
>         struct i2c_client *client = to_i2c_client(dev);
>
> -       if (device_may_wakeup(dev))
> +       if (device_may_wakeup(dev)) {
>                 enable_irq_wake(client->irq);
> +               disable_irq(client->irq);
> +       }
>
>         return 0;
>  }
> @@ -1210,8 +1212,10 @@ static int __maybe_unused edt_ft5x06_ts_resume(struct device *dev)
>  {
>         struct i2c_client *client = to_i2c_client(dev);
>
> -       if (device_may_wakeup(dev))
> +       if (device_may_wakeup(dev)) {
>                 disable_irq_wake(client->irq);
> +               enable_irq(client->irq);
> +       }
>
>         return 0;
>  }
> --
> 2.17.1
>


-- 
With Best Regards,
Andy Shevchenko