linux-kernel - Re: [PATCH] ACPI LID: increment wakeup count only when notified.

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Date:   Wed, 6 Jun 2018 09:00:43 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Ravi Chandra Sadineni <ravisadineni@...omium.org>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        Ravi Chandra Sadineni <ravisadineni@...gle.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Todd Broch <tbroch@...gle.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Rajat Jain <rajatja@...gle.com>,
        Benson Leung <bleung@...gle.com>,
        Furquan Shaikh <furquan@...omium.org>
Subject: Re: [PATCH] ACPI LID: increment wakeup count only when notified.

On Mon, Jun 4, 2018 at 8:26 PM, Ravi Chandra Sadineni
<ravisadineni@...omium.org> wrote:
> Currently ACPI LID increments wakeup count irrespective of the wake source.
> This is because we call acpi_lid_initialize_state on every resume.

I don't quite understand the connection between the two sentences
above.  Care to clarify?

> Userland deamons using wakeup_count to identify the potential wake
> source for the last wake will be thrown off by this. Instead increment
> the wakeup count only when there is a FIXED_HARDWARE/NOTFIY_STATUS event.
>
> Signed-off-by: Ravi Chandra Sadineni <ravisadineni@...omium.org>
> ---
>  drivers/acpi/button.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
> index f1cc4f9d31cd9..d40fef7241f08 100644
> --- a/drivers/acpi/button.c
> +++ b/drivers/acpi/button.c
> @@ -235,9 +235,6 @@ static int acpi_lid_notify_state(struct acpi_device *device, int state)
>                 button->last_time = ktime_get();
>         }
>
> -       if (state)
> -               acpi_pm_wakeup_event(&device->dev);
> -
>         ret = blocking_notifier_call_chain(&acpi_lid_notifier, state, device);
>         if (ret == NOTIFY_DONE)
>                 ret = blocking_notifier_call_chain(&acpi_lid_notifier, state,
> @@ -417,6 +414,7 @@ static void acpi_button_notify(struct acpi_device *device, u32 event)
>                 /* fall through */
>         case ACPI_BUTTON_NOTIFY_STATUS:
>                 input = button->input;
> +               acpi_pm_wakeup_event(&device->dev);

Not really.

There already is an acpi_pm_wakeup_event() call in the else branch below.

>                 if (button->type == ACPI_BUTTON_TYPE_LID) {
>                         mutex_lock(&button->input->mutex);
>                         users = button->input->users;
> @@ -426,7 +424,6 @@ static void acpi_button_notify(struct acpi_device *device, u32 event)
>                 } else {
>                         int keycode;
>
> -                       acpi_pm_wakeup_event(&device->dev);
>                         if (button->suspended)
>                                 break;
>
> --