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

Hi,

From: Bastien Nocera [mailto:hadess@hadess.net]
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:

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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