Re: [PATCH v2 3/4] ACPI / button: Add SW_ACPI_LID for new usage model

[Benjamin Tissoires <benjamin.tissoires@gmail.com>]

On Thu, Jul 7, 2016 at 9:10 AM, Lv Zheng <lv.zheng@intel.com> wrote:
> There are many AML tables reporting wrong initial lid state, and some of
> them never reports lid state. As a proxy layer acting between, ACPI button
> driver is not able to handle all such cases, but need to re-define the
> usage model of the ACPI lid. That is:
> 1. It's initial state is not reliable;
> 2. There may not be open event;
> 3. Userspace should only take action against the close event which is
>    reliable, always sent after a real lid close.
> This patch adds a new input key event so that new userspace programs can
> use it to handle this usage model correctly. And in the meanwhile, no old
> programs will be broken by the userspace changes.
>
> Link: https://lkml.org/2016/3/7/460
> Link: https://github.com/systemd/systemd/issues/2087
> Signed-off-by: Lv Zheng <lv.zheng@intel.com>
> Cc: Bastien Nocera: <hadess@hadess.net>
> Cc: Benjamin Tissoires <benjamin.tissoires@gmail.com>
> Cc: linux-input@vger.kernel.org
> ---
>  drivers/acpi/button.c                  |   20 ++++++++++++++------
>  include/linux/mod_devicetable.h        |    2 +-
>  include/uapi/linux/input-event-codes.h |    3 ++-
>  3 files changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
> index 148f4e5..4ef94d2 100644
> --- a/drivers/acpi/button.c
> +++ b/drivers/acpi/button.c
> @@ -130,7 +130,8 @@ static int acpi_lid_evaluate_state(struct acpi_device *device)
>         return lid_state ? 1 : 0;
>  }
>
> -static int acpi_lid_notify_state(struct acpi_device *device, int state)
> +static int acpi_lid_notify_state(struct acpi_device *device,
> +                                int state, bool notify_acpi)
>  {
>         struct acpi_button *button = acpi_driver_data(device);
>         int ret;
> @@ -138,6 +139,11 @@ static int acpi_lid_notify_state(struct acpi_device *device, int state)
>         /* input layer checks if event is redundant */
>         input_report_switch(button->input, SW_LID, !state);
>         input_sync(button->input);
> +       if (notify_acpi) {
> +               input_report_switch(button->input,
> +                                   SW_ACPI_LID, !state);
> +               input_sync(button->input);

If you use a switch, you'll never send subsequent open state if you
doesn't close it yourself.
See my comments in 5/5 and please use a KEY event instead.

> +       }
>
>         if (state)
>                 pm_wakeup_event(&device->dev, 0);
> @@ -279,7 +285,8 @@ int acpi_lid_open(void)
>  }
>  EXPORT_SYMBOL(acpi_lid_open);
>
> -static int acpi_lid_update_state(struct acpi_device *device)
> +static int acpi_lid_update_state(struct acpi_device *device,
> +                                bool notify_acpi)
>  {
>         int state;
>
> @@ -287,17 +294,17 @@ static int acpi_lid_update_state(struct acpi_device *device)
>         if (state < 0)
>                 return state;
>
> -       return acpi_lid_notify_state(device, state);
> +       return acpi_lid_notify_state(device, state, notify_acpi);
>  }
>
>  static void acpi_lid_initialize_state(struct acpi_device *device)
>  {
>         switch (lid_init_state) {
>         case ACPI_BUTTON_LID_INIT_OPEN:
> -               (void)acpi_lid_notify_state(device, 1);
> +               (void)acpi_lid_notify_state(device, 1, false);
>                 break;
>         case ACPI_BUTTON_LID_INIT_METHOD:
> -               (void)acpi_lid_update_state(device);
> +               (void)acpi_lid_update_state(device, false);
>                 break;
>         case ACPI_BUTTON_LID_INIT_IGNORE:
>         default:
> @@ -317,7 +324,7 @@ static void acpi_button_notify(struct acpi_device *device, u32 event)
>         case ACPI_BUTTON_NOTIFY_STATUS:
>                 input = button->input;
>                 if (button->type == ACPI_BUTTON_TYPE_LID) {
> -                       acpi_lid_update_state(device);
> +                       acpi_lid_update_state(device, true);
>                 } else {
>                         int keycode;
>
> @@ -436,6 +443,7 @@ static int acpi_button_add(struct acpi_device *device)
>
>         case ACPI_BUTTON_TYPE_LID:
>                 input_set_capability(input, EV_SW, SW_LID);
> +               input_set_capability(input, EV_SW, SW_ACPI_LID);

Can't we export this new event only if the _LID function is not
reliable? This could check for the module parameter lid_init_state and
only enable it for ACPI_BUTTON_LID_INIT_OPEN.

I really hope we will be able to find a reliable way to determine
whether or not the platform support reliable LID state. If not, there
might be a need to have a db of reliable switch platforms. This can be
set in the kernel or with a hwdb entry in userspace.

Cheers,
Benjamin

>                 break;
>         }
>
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index 6e4c645..1014968 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -291,7 +291,7 @@ struct pcmcia_device_id {
>  #define INPUT_DEVICE_ID_LED_MAX                0x0f
>  #define INPUT_DEVICE_ID_SND_MAX                0x07
>  #define INPUT_DEVICE_ID_FF_MAX         0x7f
> -#define INPUT_DEVICE_ID_SW_MAX         0x0f
> +#define INPUT_DEVICE_ID_SW_MAX         0x10
>
>  #define INPUT_DEVICE_ID_MATCH_BUS      1
>  #define INPUT_DEVICE_ID_MATCH_VENDOR   2
> diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
> index 737fa32..81c344c 100644
> --- a/include/uapi/linux/input-event-codes.h
> +++ b/include/uapi/linux/input-event-codes.h
> @@ -780,7 +780,8 @@
>  #define SW_ROTATE_LOCK         0x0c  /* set = rotate locked/disabled */
>  #define SW_LINEIN_INSERT       0x0d  /* set = inserted */
>  #define SW_MUTE_DEVICE         0x0e  /* set = device disabled */
> -#define SW_MAX                 0x0f
> +#define SW_ACPI_LID            0x0f  /* set = lid shut */
> +#define SW_MAX                 0x10
>  #define SW_CNT                 (SW_MAX+1)
>
>  /*
> --
> 1.7.10
>