platform/x86: intel-vbtn: Also handle tablet-mode switch on "Detachable" and...

platform/x86: intel-vbtn: Also handle tablet-mode switch on "Detachable" and "Portable" chassis-types

Commit de9647ef ("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.

Fixes: de9647ef ("platform/x86: intel-vbtn: Only activate tablet mode switch on 2-in-1's")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mario Limonciello <Mario.limonciello@dell.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

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);
 }