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Date:   Tue, 5 May 2020 14:22:05 +0000
From:   <Mario.Limonciello@...l.com>
To:     <hdegoede@...hat.com>, <dvhart@...radead.org>, <andy@...radead.org>
CC:     <linux-acpi@...r.kernel.org>,
        <platform-driver-x86@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 4/5] platform/x86: intel-vbtn: Also handle tablet-mode
 switch on "Detachable" and "Portable" chassis-types

> -----Original Message-----
> From: platform-driver-x86-owner@...r.kernel.org <platform-driver-x86-
> owner@...r.kernel.org> On Behalf Of Hans de Goede
> Sent: Tuesday, May 5, 2020 4:06 AM
> To: Limonciello, Mario; dvhart@...radead.org; andy@...radead.org
> Cc: linux-acpi@...r.kernel.org; platform-driver-x86@...r.kernel.org; linux-
> kernel@...r.kernel.org
> 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@...l.com wrote:
> >
> >
> >> -----Original Message-----
> >> From: Hans de Goede <hdegoede@...hat.com>
> >> Sent: Saturday, May 2, 2020 1:30 PM
> >> To: Darren Hart; Andy Shevchenko; Limonciello, Mario
> >> Cc: Hans de Goede; linux-acpi@...r.kernel.org; platform-driver-
> >> x86@...r.kernel.org; linux-kernel@...r.kernel.org
> >> 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@...hat.com>
> >> ---
> >> 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.

> 
> > Reviewed-by: Mario Limonciello <Mario.limonciello@...l.com>
> 
> Thank you.
> 
> Regards,
> 
> Hans
> 
> 
> 
> 
> >> ---
> >>   drivers/platform/x86/intel-vbtn.c | 12 +++++++++++-
> >>   1 file changed, 11 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/platform/x86/intel-vbtn.c b/drivers/platform/x86/intel-
> >> vbtn.c
> >> index 500fae82e12c..4921fc15dc6c 100644
> >> --- a/drivers/platform/x86/intel-vbtn.c
> >> +++ b/drivers/platform/x86/intel-vbtn.c
> >> @@ -158,12 +158,22 @@ static void detect_tablet_mode(struct platform_device
> >> *device)
> >>   static bool intel_vbtn_has_switches(acpi_handle handle)
> >>   {
> >>   	const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
> >> +	unsigned long chassis_type_int;
> >>   	unsigned long long vgbs;
> >>   	acpi_status status;
> >>
> >> -	if (!(chassis_type && strcmp(chassis_type, "31") == 0))
> >> +	if (kstrtoul(chassis_type, 10, &chassis_type_int))
> >>   		return false;
> >>
> >> +	switch (chassis_type_int) {
> >> +	case  8: /* Portable */
> >> +	case 31: /* Convertible */
> >> +	case 32: /* Detachable */
> >> +		break;
> >> +	default:
> >> +		return false;
> >> +	}
> >> +
> >>   	status = acpi_evaluate_integer(handle, "VGBS", NULL, &vgbs);
> >>   	return ACPI_SUCCESS(status);
> >>   }
> >> --
> >> 2.26.0
> >

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