platform/x86/intel: hid: Add DMI switches allow list

Some devices, even non convertible ones, can send incorrect
SW_TABLET_MODE reports.

Add an allow list and accept such reports only from devices in it.

Bug reported for Dell XPS 17 9710 on:
https://gitlab.freedesktop.org/libinput/libinput/-/issues/662

Reported-by: Tobias Gurtzick <magic@wizardtales.com>
Suggested-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Tobias Gurtzick <magic@wizardtales.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Link: https://lore.kernel.org/r/20210920160312.9787-1-jose.exposito89@gmail.com
[hdegoede@redhat.com: Check dmi_switches_auto_add_allow_list only once]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/drivers/platform/x86/intel/hid.c b/drivers/platform/x86/intel/hid.c
index a33a582..0859894 100644
--- a/drivers/platform/x86/intel/hid.c
+++ b/drivers/platform/x86/intel/hid.c
@@ -118,12 +118,30 @@
 	{ }
 };
 
+/*
+ * Some devices, even non convertible ones, can send incorrect SW_TABLET_MODE
+ * reports. Accept such reports only from devices in this list.
+ */
+static const struct dmi_system_id dmi_auto_add_switch[] = {
+	{
+		.matches = {
+			DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "31" /* Convertible */),
+		},
+	},
+	{
+		.matches = {
+			DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "32" /* Detachable */),
+		},
+	},
+	{} /* Array terminator */
+};
+
 struct intel_hid_priv {
 	struct input_dev *input_dev;
 	struct input_dev *array;
 	struct input_dev *switches;
 	bool wakeup_mode;
-	bool dual_accel;
+	bool auto_add_switch;
 };
 
 #define HID_EVENT_FILTER_UUID	"eeec56b3-4442-408f-a792-4edd4d758054"
@@ -452,10 +470,8 @@
 	 * Some convertible have unreliable VGBS return which could cause incorrect
 	 * SW_TABLET_MODE report, in these cases we enable support when receiving
 	 * the first event instead of during driver setup.
-	 *
-	 * See dual_accel_detect.h for more info on the dual_accel check.
 	 */
-	if (!priv->switches && !priv->dual_accel && (event == 0xcc || event == 0xcd)) {
+	if (!priv->switches && priv->auto_add_switch && (event == 0xcc || event == 0xcd)) {
 		dev_info(&device->dev, "switch event received, enable switches supports\n");
 		err = intel_hid_switches_setup(device);
 		if (err)
@@ -596,7 +612,8 @@
 		return -ENOMEM;
 	dev_set_drvdata(&device->dev, priv);
 
-	priv->dual_accel = dual_accel_detect();
+	/* See dual_accel_detect.h for more info on the dual_accel check. */
+	priv->auto_add_switch = dmi_check_system(dmi_auto_add_switch) && !dual_accel_detect();
 
 	err = intel_hid_input_setup(device);
 	if (err) {