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

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Date:   Mon, 4 May 2020 15:37:51 +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: 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.

Reviewed-by: Mario Limonciello <Mario.limonciello@...l.com>

> ---
>  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