[PATCH AUTOSEL 5.13 04/12] platform/x86: Add and use a dual_accel_detect() helper

From: Sasha Levin
Date: Mon Aug 16 2021 - 20:35:48 EST


From: Hans de Goede <hdegoede@xxxxxxxxxx>

[ Upstream commit 153cca9caa81ca8912a70528daca4b9a523c6898 ]

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@xxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Link: https://lore.kernel.org/r/20210729082134.6683-1-hdegoede@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/platform/x86/Kconfig | 3 +
drivers/platform/x86/dual_accel_detect.h | 75 ++++++++++++++++++++++++
drivers/platform/x86/intel-hid.c | 21 ++-----
drivers/platform/x86/intel-vbtn.c | 18 +++++-
drivers/platform/x86/thinkpad_acpi.c | 3 +-
5 files changed, 101 insertions(+), 19 deletions(-)
create mode 100644 drivers/platform/x86/dual_accel_detect.h

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 60592fb88e7a..e878ac192758 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -507,6 +507,7 @@ config THINKPAD_ACPI
depends on RFKILL || RFKILL = n
depends on ACPI_VIDEO || ACPI_VIDEO = n
depends on BACKLIGHT_CLASS_DEVICE
+ depends on I2C
select ACPI_PLATFORM_PROFILE
select HWMON
select NVRAM
@@ -701,6 +702,7 @@ config INTEL_HID_EVENT
tristate "INTEL HID Event"
depends on ACPI
depends on INPUT
+ depends on I2C
select INPUT_SPARSEKMAP
help
This driver provides support for the Intel HID Event hotkey interface.
@@ -752,6 +754,7 @@ config INTEL_VBTN
tristate "INTEL VIRTUAL BUTTON"
depends on ACPI
depends on INPUT
+ depends on I2C
select INPUT_SPARSEKMAP
help
This driver provides support for the Intel Virtual Button interface.
diff --git a/drivers/platform/x86/dual_accel_detect.h b/drivers/platform/x86/dual_accel_detect.h
new file mode 100644
index 000000000000..1a069159da91
--- /dev/null
+++ b/drivers/platform/x86/dual_accel_detect.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Helper code to detect 360 degree hinges (yoga) style 2-in-1 devices using 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 drivers/platform/x86 drivers is incorrect. These drivers use the detection
+ * code in this file to disable SW_TABLET_MODE reporting to avoid reporting broken info
+ * (instead userspace can derive the status itself by directly reading the 2 accels).
+ */
+
+#include <linux/acpi.h>
+#include <linux/i2c.h>
+
+static int dual_accel_i2c_resource_count(struct acpi_resource *ares, void *data)
+{
+ struct acpi_resource_i2c_serialbus *sb;
+ int *count = data;
+
+ if (i2c_acpi_get_i2c_resource(ares, &sb))
+ *count = *count + 1;
+
+ return 1;
+}
+
+static int dual_accel_i2c_client_count(struct acpi_device *adev)
+{
+ int ret, count = 0;
+ LIST_HEAD(r);
+
+ ret = acpi_dev_get_resources(adev, &r, dual_accel_i2c_resource_count, &count);
+ if (ret < 0)
+ return ret;
+
+ acpi_dev_free_resource_list(&r);
+ return count;
+}
+
+static bool dual_accel_detect_bosc0200(void)
+{
+ struct acpi_device *adev;
+ int count;
+
+ adev = acpi_dev_get_first_match_dev("BOSC0200", NULL, -1);
+ if (!adev)
+ return false;
+
+ count = dual_accel_i2c_client_count(adev);
+
+ acpi_dev_put(adev);
+
+ return count == 2;
+}
+
+static bool dual_accel_detect(void)
+{
+ /* Systems which use a pair of accels with KIOX010A / KIOX020A ACPI ids */
+ if (acpi_dev_present("KIOX010A", NULL, -1))
+ return true;
+
+ /* Systems which use a single DUAL250E ACPI device to model 2 accels */
+ if (acpi_dev_present("DUAL250E", NULL, -1))
+ return true;
+
+ /* Systems which use a single BOSC0200 ACPI device to model 2 accels */
+ if (dual_accel_detect_bosc0200())
+ return true;
+
+ return false;
+}
diff --git a/drivers/platform/x86/intel-hid.c b/drivers/platform/x86/intel-hid.c
index 078648a9201b..7135d720af60 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)
@@ -121,6 +122,7 @@ 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"
@@ -450,22 +452,9 @@ 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)
@@ -606,6 +595,8 @@ 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");
diff --git a/drivers/platform/x86/intel-vbtn.c b/drivers/platform/x86/intel-vbtn.c
index 888a764efad1..309166431063 100644
--- a/drivers/platform/x86/intel-vbtn.c
+++ b/drivers/platform/x86/intel-vbtn.c
@@ -14,6 +14,7 @@
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/suspend.h>
+#include "dual_accel_detect.h"

/* Returned when NOT in tablet mode on some HP Stream x360 11 models */
#define VGBS_TABLET_MODE_FLAG_ALT 0x10
@@ -66,6 +67,7 @@ static const struct key_entry intel_vbtn_switchmap[] = {
struct intel_vbtn_priv {
struct input_dev *buttons_dev;
struct input_dev *switches_dev;
+ bool dual_accel;
bool has_buttons;
bool has_switches;
bool wakeup_mode;
@@ -160,6 +162,10 @@ static void notify_handler(acpi_handle handle, u32 event, void *context)
input_dev = priv->buttons_dev;
} else if ((ke = sparse_keymap_entry_from_scancode(priv->switches_dev, event))) {
if (!priv->has_switches) {
+ /* See dual_accel_detect.h for more info */
+ if (priv->dual_accel)
+ return;
+
dev_info(&device->dev, "Registering Intel Virtual Switches input-dev after receiving a switch event\n");
ret = input_register_device(priv->switches_dev);
if (ret)
@@ -248,11 +254,15 @@ static const struct dmi_system_id dmi_switches_allow_list[] = {
{} /* Array terminator */
};

-static bool intel_vbtn_has_switches(acpi_handle handle)
+static bool intel_vbtn_has_switches(acpi_handle handle, bool dual_accel)
{
unsigned long long vgbs;
acpi_status status;

+ /* See dual_accel_detect.h for more info */
+ if (dual_accel)
+ return false;
+
if (!dmi_check_system(dmi_switches_allow_list))
return false;

@@ -263,13 +273,14 @@ static bool intel_vbtn_has_switches(acpi_handle handle)
static int intel_vbtn_probe(struct platform_device *device)
{
acpi_handle handle = ACPI_HANDLE(&device->dev);
- bool has_buttons, has_switches;
+ bool dual_accel, has_buttons, has_switches;
struct intel_vbtn_priv *priv;
acpi_status status;
int err;

+ dual_accel = dual_accel_detect();
has_buttons = acpi_has_method(handle, "VBDL");
- has_switches = intel_vbtn_has_switches(handle);
+ has_switches = intel_vbtn_has_switches(handle, dual_accel);

if (!has_buttons && !has_switches) {
dev_warn(&device->dev, "failed to read Intel Virtual Button driver\n");
@@ -281,6 +292,7 @@ static int intel_vbtn_probe(struct platform_device *device)
return -ENOMEM;
dev_set_drvdata(&device->dev, priv);

+ priv->dual_accel = dual_accel;
priv->has_buttons = has_buttons;
priv->has_switches = has_switches;

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index edd71e744d27..f8cfb529d1a2 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -73,6 +73,7 @@
#include <linux/uaccess.h>
#include <acpi/battery.h>
#include <acpi/video.h>
+#include "dual_accel_detect.h"

/* ThinkPad CMOS commands */
#define TP_CMOS_VOLUME_DOWN 0
@@ -3232,7 +3233,7 @@ static int hotkey_init_tablet_mode(void)
* the laptop/tent/tablet mode to the EC. The bmc150 iio driver
* does not support this, so skip the hotkey on these models.
*/
- if (has_tablet_mode && !acpi_dev_present("BOSC0200", "1", -1))
+ if (has_tablet_mode && !dual_accel_detect())
tp_features.hotkey_tablet = TP_HOTKEY_TABLET_USES_GMMS;
type = "GMMS";
} else if (acpi_evalf(hkey_handle, &res, "MHKG", "qd")) {
--
2.30.2