Re: [PATCH 4/5] platform/x86: intel-vbtn: Also handle tablet-mode switch on "Detachable" and "Portable" chassis-types

From: Hans de Goede
Date: Thu May 07 2020 - 07:25:54 EST


Hi,

On 5/5/20 4:27 PM, Andy Shevchenko wrote:
On Tue, May 5, 2020 at 5:22 PM <Mario.Limonciello@xxxxxxxx> wrote:

-----Original Message-----
From: platform-driver-x86-owner@xxxxxxxxxxxxxxx <platform-driver-x86-
owner@xxxxxxxxxxxxxxx> On Behalf Of Hans de Goede
Sent: Tuesday, May 5, 2020 4:06 AM
To: Limonciello, Mario; dvhart@xxxxxxxxxxxxx; andy@xxxxxxxxxxxxx
Cc: linux-acpi@xxxxxxxxxxxxxxx; platform-driver-x86@xxxxxxxxxxxxxxx; linux-
kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH 4/5] platform/x86: intel-vbtn: Also handle tablet-mode
switch on "Detachable" and "Portable" chassis-types


[EXTERNAL EMAIL]

Hi,

On 5/4/20 5:37 PM, Mario.Limonciello@xxxxxxxx wrote:


-----Original Message-----
From: Hans de Goede <hdegoede@xxxxxxxxxx>
Sent: Saturday, May 2, 2020 1:30 PM
To: Darren Hart; Andy Shevchenko; Limonciello, Mario
Cc: Hans de Goede; linux-acpi@xxxxxxxxxxxxxxx; platform-driver-
x86@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: [PATCH 4/5] platform/x86: intel-vbtn: Also handle tablet-mode
switch
on "Detachable" and "Portable" chassis-types


[EXTERNAL EMAIL]

Commit de9647efeaa9 ("platform/x86: intel-vbtn: Only activate tablet mode
switch on 2-in-1's") added a DMI chassis-type check to avoid accidentally
reporting SW_TABLET_MODE = 1 to userspace on laptops.

Some devices with a detachable keyboard and using the intel-vbnt (INT33D6)
interface to report if they are in tablet mode (keyboard detached) or not,
report 32 / "Detachable" as chassis-type, e.g. the HP Pavilion X2 series.

Other devices with a detachable keyboard and using the intel-vbnt (INT33D6)
interface to report SW_TABLET_MODE, report 8 / "Portable" as chassis-type.
The Dell Venue 11 Pro 7130 is an example of this.

Extend the DMI chassis-type check to also accept Portables and Detachables
so that the intel-vbtn driver will report SW_TABLET_MODE on these devices.

Note the chassis-type check was originally added to avoid a false-positive
tablet-mode report on the Dell XPS 9360 laptop. To the best of my knowledge
that laptop is using a chassis-type of 9 / "Laptop", so after this commit
we still ignore the tablet-switch for that chassis-type.

Yes that's correct.


Fixes: de9647efeaa9 ("platform/x86: intel-vbtn: Only activate tablet mode
switch on 2-in-1's")
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Looking at the Microsoft Windows documentation for tablet-mode reporting:
https://docs.microsoft.com/en-us/windows-hardware/drivers/gpiobtn/button-
implementation

Then the presence of a tablet-mode switch is indicated by the presence
of a PNP0C60 compatible ACPI devices. There are 2 ways in which this device
can report the tablet-mode. 1. Directly providing a GpioInt resource inside
the PNP0C60 device, 2. Through injecting events from a Windows driver.

It seems that the intel-vbtn / the INT33D6 ACPI device is the ACPI side
of Intel's generic solution for the case where the tablet-mode comes from
the embedded-controller and needs to be "injected".

This all suggests that it might be better to replace the chassis-type
check with a acpi_dev_present("PNP0C60", NULL, -1) check.

Mario, can you provide an acpidump and alsa-info.sh output for the
Dell XPS 9360, so that I can check if that might help with the issue
there, and thus is a potential candidate to replace the chassis-type
check?

Unfortunately with WFH right now, I don't have access to a XPS 9630 to
double check the patch series.

However I do agree this should be a good approach.

Ok, so lets stick with the chassis-type check (as amended by this patch)
for now then. Then once you are able to go to your office again, we
can examine the acpi_dev_present("PNP0C60", NULL, -1) alternative.

I know XPS 13's are pretty popular, perhaps someone on the mailing list who has
one can share ACPI dump in the interim.

https://github.com/intel/dptfxtract/issues/13

Good one.

So this has:

Device (CIND)
{
Name (_HID, "INT33D3" /* Intel GPIO Buttons */) // _HID: Hardware I
Name (_CID, "PNP0C60" /* Display Sensor Device */) // _CID: Compati
Method (_STA, 0, Serialized) // _STA: Status
{
If ((OSYS >= 0x07DC))
{
Return (0x0F)
}

Return (Zero)
}
}

And OSYS >= 0x07DC checks for "Windows 2012" which Linux does advertise,
so despite not having a tablet-mode(switch) the XPS 9360 still has a
PNP0C60 ACPI device and will report 0xf (present) as status for it,
so a acpi_dev_present("PNP0C60", NULL, -1) check will succeed on it.

Conclusion: such a check is not a valid alternative for checking DMI
chassis-types (and from that pov this series thus is ready for merging).

Regards,

Hans