Re: [PATCH v4 1/2] ACPI / button: Add KEY_LID_OPEN/KEY_LID_CLOSE for new usage model

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

On Tuesday, July 19, 2016 04:11:02 PM Lv Zheng wrote:
> There are many AML tables reporting wrong initial lid state, and some of
> them never report lid open 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 an open event;
> 3. Userspace should only take action against the close event which is
>    reliable, always sent after a real lid close.
> 
> OTOH, using an input switch event for the lid device on such platforms can
> cause the loss of the close event, but the platforms purposely want to use
> these close events to trigger power saving actions.
> 
> So we need to introduce a new ABI, which is input key events based, not
> input switch events based.
> 
> This patch adds a set of new input key events so that the new userspace
> programs can use them to handle this usage model correctly. And in the
> meanwhile, the old input switch event is kept so that no old programs will
> be broken by the ABI change.
> 
> Signed-off-by: Lv Zheng <lv.zheng@intel.com>
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Cc: Benjamin Tissoires <benjamin.tissoires@gmail.com>
> Cc: Bastien Nocera: <hadess@hadess.net>
> Cc: linux-input@vger.kernel.org

Dmitry, any objections here?

> ---
>  drivers/acpi/button.c                  |   34 +++++++++++++++++++++++++++++++-
>  include/uapi/linux/input-event-codes.h |    7 +++++++
>  2 files changed, 40 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
> index 148f4e5..dd16879 100644
> --- a/drivers/acpi/button.c
> +++ b/drivers/acpi/button.c
> @@ -104,6 +104,8 @@ struct acpi_button {
>  	struct input_dev *input;
>  	char phys[32];			/* for input device */
>  	unsigned long pushed;
> +	int last_state;
> +	unsigned long timestamp;
>  	bool suspended;
>  };
>  
> @@ -111,6 +113,10 @@ static BLOCKING_NOTIFIER_HEAD(acpi_lid_notifier);
>  static struct acpi_device *lid_device;
>  static u8 lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
>  
> +static unsigned long lid_report_interval __read_mostly = 500;
> +module_param(lid_report_interval, ulong, 0644);
> +MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
> +
>  /* --------------------------------------------------------------------------
>                                FS Interface (/proc)
>     -------------------------------------------------------------------------- */
> @@ -133,12 +139,34 @@ static int acpi_lid_evaluate_state(struct acpi_device *device)
>  static int acpi_lid_notify_state(struct acpi_device *device, int state)
>  {
>  	struct acpi_button *button = acpi_driver_data(device);
> +	int keycode;
> +	unsigned long timeout;
>  	int ret;
>  
> -	/* input layer checks if event is redundant */
> +	/*
> +	 * Send the switch event.
> +	 * The input layer checks if the event is redundant.
> +	 */
>  	input_report_switch(button->input, SW_LID, !state);
>  	input_sync(button->input);
>  
> +	/*
> +	 * Send the key event.
> +	 * The input layer doesn't check if the event is redundant.
> +	 */
> +	timeout = button->timestamp +
> +		  msecs_to_jiffies(lid_report_interval);
> +	if (button->last_state != !!state ||
> +	    time_after(jiffies, timeout)) {
> +		keycode = state ? KEY_LID_OPEN : KEY_LID_CLOSE;
> +		input_report_key(button->input, keycode, 1);
> +		input_sync(button->input);
> +		input_report_key(button->input, keycode, 0);
> +		input_sync(button->input);
> +		button->last_state = !!state;
> +		button->timestamp = jiffies;
> +	}
> +
>  	if (state)
>  		pm_wakeup_event(&device->dev, 0);
>  
> @@ -407,6 +435,8 @@ static int acpi_button_add(struct acpi_device *device)
>  		strcpy(name, ACPI_BUTTON_DEVICE_NAME_LID);
>  		sprintf(class, "%s/%s",
>  			ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
> +		button->last_state = !!acpi_lid_evaluate_state(device);
> +		button->timestamp = jiffies;
>  	} else {
>  		printk(KERN_ERR PREFIX "Unsupported hid [%s]\n", hid);
>  		error = -ENODEV;
> @@ -436,6 +466,8 @@ 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_KEY, KEY_LID_OPEN);
> +		input_set_capability(input, EV_KEY, KEY_LID_CLOSE);
>  		break;
>  	}
>  
> diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
> index 737fa32..b062fe1 100644
> --- a/include/uapi/linux/input-event-codes.h
> +++ b/include/uapi/linux/input-event-codes.h
> @@ -641,6 +641,13 @@
>   * e.g. teletext or data broadcast application (MHEG, MHP, HbbTV, etc.)
>   */
>  #define KEY_DATA			0x275
> +/*
> + * Key events sent by the lid drivers.
> + * The drivers may not be able to send paired "open"/"close" events, in
> + * which case, they send KEY_LID_OPEN/KEY_LID_CLOSE instead of SW_LID.
> + */
> +#define KEY_LID_OPEN			0x278
> +#define KEY_LID_CLOSE			0x279
>  
>  #define BTN_TRIGGER_HAPPY		0x2c0
>  #define BTN_TRIGGER_HAPPY1		0x2c0

To this part in particular?

Thanks,
Rafael