platform/x86: Add and use a dual_accel_detect() helper

Various 360 degree hinges (yoga) style 2-in-1 devices use 2 accelerometers
to allow the OS to determine the angle between the display and the base of
the device.

On Windows these are read by a special HingeAngleService process which
calls undocumented ACPI methods, to let the firmware know if the 2-in-1 is
in tablet- or laptop-mode. The firmware may use this to disable the kbd and
touchpad to avoid spurious input in tablet-mode as well as to report
SW_TABLET_MODE info to the OS.

Since Linux does not call these undocumented methods, the SW_TABLET_MODE
info reported by various pdx86 drivers is incorrect on these devices.

Before this commit the intel-hid and thinkpad_acpi code already had 2
hardcoded checks for ACPI hardware-ids of dual-accel sensors to avoid
reporting broken info.

And now we also have a bug-report about the same problem in the intel-vbtn
code. Since there are at least 3 different ACPI hardware-ids in play, add
a new dual_accel_detect() helper which checks for all 3, rather then
adding different hardware-ids to the drivers as bug-reports trickle in.
Having shared code which checks all known hardware-ids is esp. important
for the intel-hid and intel-vbtn drivers as these are generic drivers
which are used on a lot of devices.

The BOSC0200 hardware-id requires special handling, because often it is
used for a single-accelerometer setup. Only in a few cases it refers to
a dual-accel setup, in which case there will be 2 I2cSerialBus resources
in the device's resource-list, so the helper checks for this.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209011
Reported-and-tested-by: Julius Lehmann <julius@devpi.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210729082134.6683-1-hdegoede@redhat.com

1 files changed, 6 insertions, 15 deletions

diff --git a/drivers/platform/x86/intel-hid.c b/drivers/platform/x86/intel-hid.c
index e5fbe017f8e1..2e4e97a626a5 100644
--- a/drivers/platform/x86/intel-hid.c
+++ b/drivers/platform/x86/intel-hid.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/suspend.h>
+#include "dual_accel_detect.h"
 
 /* When NOT in tablet mode, VGBS returns with the flag 0x40 */
 #define TABLET_MODE_FLAG BIT(6)
@@ -122,6 +123,7 @@ struct intel_hid_priv {
 	struct input_dev *array;
 	struct input_dev *switches;
 	bool wakeup_mode;
+	bool dual_accel;
 };
 
 #define HID_EVENT_FILTER_UUID	"eeec56b3-4442-408f-a792-4edd4d758054"
@@ -451,22 +453,9 @@ static void notify_handler(acpi_handle handle, u32 event, void *context)
 	 * SW_TABLET_MODE report, in these cases we enable support when receiving
 	 * the first event instead of during driver setup.
 	 *
-	 * Some 360 degree hinges (yoga) style 2-in-1 devices use 2 accelerometers
-	 * to allow the OS to determine the angle between the display and the base
-	 * of the device. On Windows these are read by a special HingeAngleService
-	 * process which calls an ACPI DSM (Device Specific Method) on the
-	 * ACPI KIOX010A device node for the sensor in the display, to let the
-	 * firmware know if the 2-in-1 is in tablet- or laptop-mode so that it can
-	 * disable the kbd and touchpad to avoid spurious input in tablet-mode.
-	 *
-	 * The linux kxcjk1013 driver calls the DSM for this once at probe time
-	 * to ensure that the builtin kbd and touchpad work. On some devices this
-	 * causes a "spurious" 0xcd event on the intel-hid ACPI dev. In this case
-	 * there is not a functional tablet-mode switch, so we should not register
-	 * the tablet-mode switch device.
+	 * See dual_accel_detect.h for more info on the dual_accel check.
 	 */
-	if (!priv->switches && (event == 0xcc || event == 0xcd) &&
-	    !acpi_dev_present("KIOX010A", NULL, -1)) {
+	if (!priv->switches && !priv->dual_accel && (event == 0xcc || event == 0xcd)) {
 		dev_info(&device->dev, "switch event received, enable switches supports\n");
 		err = intel_hid_switches_setup(device);
 		if (err)
@@ -607,6 +596,8 @@ static int intel_hid_probe(struct platform_device *device)
 		return -ENOMEM;
 	dev_set_drvdata(&device->dev, priv);
 
+	priv->dual_accel = dual_accel_detect();
+
 	err = intel_hid_input_setup(device);
 	if (err) {
 		pr_err("Failed to setup Intel HID hotkeys\n");