RE: [PATCH v2 4/4] ACPI / button: Add document for ACPI control method lid device restrictions

[Zheng, Lv]

Hi,

> From: Bastien Nocera [mailto:hadess@xxxxxxxxxx]
> Subject: Re: [PATCH v2 4/4] ACPI / button: Add document for ACPI control
> method lid device restrictions
> 
> On Mon, 2016-07-11 at 03:20 +0000, Zheng, Lv wrote:
> >
> <snip>
> > > This worries me as there is no plan after "During the period the
> > > userspace hasn't been switched to use the new event".
> > >
> > > I really hope you'll keep sending SW_LID for reliable LID
> > > platforms,
> > > and not remove it entirely as you will break platforms.
> >
> > [Lv Zheng]
> > We won't remove SW_LID from the kernel :).
> >
> > And we haven't removed SW_LID from the acpi button driver.
> > We'll just stop sending "initial lid state" from acpi button driver,
> > i.e., the behavior carried out by "button.lid_init_state=ignore".
> >
> > Maybe it is not sufficient, after the userspace has been changed to
> > support the new event, we should stop sending SW_LID from acpi button
> > driver.
> 
> For the affected devices? Sure, but I don't think that's a reasonable
> thing to do for "all" the devices. We have a majority of laptops where
> this isn't a problem, and it's not even a problem any more on one of
> the devices that triggered this discussion (there's a patch for make
> the LID status match reality for the Surface 3).
[Lv Zheng] 
It looks, even with this fixed, there are tables never generating "lid open" event.
Thus the lid notification is definitely not a "switch event".

Thanks and best regards
-Lv