RE: [PATCH v3 3/3] ACPI / button: Add quirks for initial lid state notification

["Zheng, Lv" <lv.zheng@intel.com>]

Hi,

> From: Bastien Nocera [mailto:hadess@hadess.net]
> 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"
[Lv Zheng] 
Thanks for pointing out, I'll send an UPDATE to this.

> 
> > 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.
[Lv Zheng] 
IMO, the ACPI lid driver should be responsible for sending lid key event (especially "close") to the user space.
So if someone need to implement an ACPI lid key event quirk, we could help to implement it from the kernel space.
And since the initial lid state is not stable, we have to stop doing quirks around it inside of the Linux kernel, or inside of the customized AML tables.
User space can still access /proc/acpi/button/lid/LID0/state, but should stop thinking that it is reliable.

These are what I can conclude from the bugs.

Thanks and best regards
-Lv

> 
> (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@intel.com>
> > Cc: Bastien Nocera: <hadess@hadess.net>
> > Cc: Benjamin Tissoires <benjamin.tissoires@gmail.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);