linux-kernel - Re: [PATCH v3 3/3] ACPI / button: Add quirks for initial lid state notification

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Date:	Wed, 01 Jun 2016 13:01:11 +0200
From:	Bastien Nocera <hadess@...ess.net>
To:	Lv Zheng <lv.zheng@...el.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>
Cc:	Lv Zheng <zetalog@...il.com>, linux-kernel@...r.kernel.org,
	linux-acpi@...r.kernel.org,
	Benjamin Tissoires <benjamin.tissoires@...il.com>
Subject: Re: [PATCH v3 3/3] ACPI / button: Add quirks for initial lid state
 notification

On Wed, 2016-06-01 at 18:10 +0800, Lv Zheng wrote:
> Linux userspace (systemd-logind) keeps on rechecking lid state when the
> lid state is closed. If it failed to update the lid state to open after
> boot/resume, the system suspending right after the boot/resume could be
> resulted.
> Graphics drivers also uses the lid notifications to implment
> MODESET_ON_LID_OPEN option.

"implement"

> Before the situation is improved from the userspace and from the graphics
> driver, users can simply configure ACPI button driver to send initial
> "open" lid state using button.lid_init_state=open to avoid such kind of
> issues. And our ultimate target should be making
> button.lid_init_state=ignore the default behavior. This patch implements
> the 2 options and keep the old behavior (button.lid_init_state=method).

I still don't think it's reasonable to expect any changes in user-space 
unless you start documenting what the API to user-space actually is.

(I work on UPower, which also exports that information, and which gets
used in gnome-settings-daemon in a number of ways)

> Link 1: https://lkml.org/2016/3/7/460
> Link 2: https://github.com/systemd/systemd/issues/2087
> Signed-off-by: Lv Zheng <lv.zheng@...el.com>
> Cc: Bastien Nocera: <hadess@...ess.net>
> Cc: Benjamin Tissoires <benjamin.tissoires@...il.com>
> ---
>  drivers/acpi/button.c |   61
> +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 61 insertions(+)
> 
> diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
> index 6e291c1..148f4e5 100644
> --- a/drivers/acpi/button.c
> +++ b/drivers/acpi/button.c
> @@ -53,6 +53,10 @@
>  #define ACPI_BUTTON_DEVICE_NAME_LID	"Lid Switch"
>  #define ACPI_BUTTON_TYPE_LID		0x05
>  
> +#define ACPI_BUTTON_LID_INIT_IGNORE	0x00
> +#define ACPI_BUTTON_LID_INIT_OPEN	0x01
> +#define ACPI_BUTTON_LID_INIT_METHOD	0x02
> +
>  #define _COMPONENT		ACPI_BUTTON_COMPONENT
>  ACPI_MODULE_NAME("button");
>  
> @@ -105,6 +109,7 @@ struct acpi_button {
>  
>  static BLOCKING_NOTIFIER_HEAD(acpi_lid_notifier);
>  static struct acpi_device *lid_device;
> +static u8 lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
>  
>  /* ---------------------------------------------------------------
> -----------
>                                FS Interface (/proc)
> @@ -285,6 +290,21 @@ static int acpi_lid_update_state(struct
> acpi_device *device)
>  	return acpi_lid_notify_state(device, state);
>  }
>  
> +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);
> +		break;
> +	case ACPI_BUTTON_LID_INIT_METHOD:
> +		(void)acpi_lid_update_state(device);
> +		break;
> +	case ACPI_BUTTON_LID_INIT_IGNORE:
> +	default:
> +		break;
> +	}
> +}
> +
>  static void acpi_button_notify(struct acpi_device *device, u32
> event)
>  {
>  	struct acpi_button *button = acpi_driver_data(device);
> @@ -341,6 +361,8 @@ static int acpi_button_resume(struct device *dev)
>  	struct acpi_button *button = acpi_driver_data(device);
>  
>  	button->suspended = false;
> +	if (button->type == ACPI_BUTTON_TYPE_LID)
> +		acpi_lid_initialize_state(device);
>  	return 0;
>  }
>  #endif
> @@ -421,6 +443,7 @@ static int acpi_button_add(struct acpi_device
> *device)
>  	if (error)
>  		goto err_remove_fs;
>  	if (button->type == ACPI_BUTTON_TYPE_LID) {
> +		acpi_lid_initialize_state(device);
>  		/*
>  		 * This assumes there's only one lid device, or if
> there are
>  		 * more we only care about the last one...
> @@ -450,4 +473,42 @@ static int acpi_button_remove(struct acpi_device
> *device)
>  	return 0;
>  }
>  
> +static int param_set_lid_init_state(const char *val, struct
> kernel_param *kp)
> +{
> +	int result = 0;
> +
> +	if (!strncmp(val, "open", sizeof("open") - 1)) {
> +		lid_init_state = ACPI_BUTTON_LID_INIT_OPEN;
> +		pr_info("Notify initial lid state as open\n");
> +	} else if (!strncmp(val, "method", sizeof("method") - 1)) {
> +		lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
> +		pr_info("Notify initial lid state with _LID return
> value\n");
> +	} else if (!strncmp(val, "ignore", sizeof("ignore") - 1)) {
> +		lid_init_state = ACPI_BUTTON_LID_INIT_IGNORE;
> +		pr_info("Do not notify initial lid state\n");
> +	} else
> +		result = -EINVAL;
> +	return result;
> +}
> +
> +static int param_get_lid_init_state(char *buffer, struct
> kernel_param *kp)
> +{
> +	switch (lid_init_state) {
> +	case ACPI_BUTTON_LID_INIT_OPEN:
> +		return sprintf(buffer, "open");
> +	case ACPI_BUTTON_LID_INIT_METHOD:
> +		return sprintf(buffer, "method");
> +	case ACPI_BUTTON_LID_INIT_IGNORE:
> +		return sprintf(buffer, "ignore");
> +	default:
> +		return sprintf(buffer, "invalid");
> +	}
> +	return 0;
> +}
> +
> +module_param_call(lid_init_state,
> +		  param_set_lid_init_state,
> param_get_lid_init_state,
> +		  NULL, 0644);
> +MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial
> state");
> +
>  module_acpi_driver(acpi_button_driver);