Patch "HID: multitouch: enable palm rejection for Windows Precision Touchpad" has been added to the 4.4-stable tree

@@ -61,6 +61,7 @@ MODULE_LICENSE("GPL");
 #define MT_QUIRK_ALWAYS_VALID		(1 << 4)
 #define MT_QUIRK_VALID_IS_INRANGE	(1 << 5)
 #define MT_QUIRK_VALID_IS_CONFIDENCE	(1 << 6)
+#define MT_QUIRK_CONFIDENCE		(1 << 7)
 #define MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE	(1 << 8)
 #define MT_QUIRK_NO_AREA		(1 << 9)
 #define MT_QUIRK_IGNORE_DUPLICATES	(1 << 10)

@@ -78,6 +79,7 @@ struct mt_slot {
 	__s32 contactid;	/* the device ContactID assigned to this slot */
 	bool touch_state;	/* is the touch valid? */
 	bool inrange_state;	/* is the finger in proximity of the sensor? */
+	bool confidence_state;  /* is the touch made by a finger? */
 };
 
 struct mt_class {

@@ -502,6 +504,9 @@ static int mt_touch_input_mapping(struct
 			mt_store_field(usage, td, hi);
 			return 1;
 		case HID_DG_CONFIDENCE:
+			if (cls->name == MT_CLS_WIN_8 &&
+				field->application == HID_DG_TOUCHPAD)
+				cls->quirks |= MT_QUIRK_CONFIDENCE;
 			mt_store_field(usage, td, hi);
 			return 1;
 		case HID_DG_TIPSWITCH:

@@ -614,6 +619,7 @@ static void mt_complete_slot(struct mt_d
 		return;
 
 	if (td->curvalid || (td->mtclass.quirks & MT_QUIRK_ALWAYS_VALID)) {
+		int active;
 		int slotnum = mt_compute_slot(td, input);
 		struct mt_slot *s = &td->curdata;
 		struct input_mt *mt = input->mt;

@@ -628,10 +634,14 @@ static void mt_complete_slot(struct mt_d
 				return;
 		}
 
+		if (!(td->mtclass.quirks & MT_QUIRK_CONFIDENCE))
+			s->confidence_state = 1;
+		active = (s->touch_state || s->inrange_state) &&
+							s->confidence_state;
+
 		input_mt_slot(input, slotnum);
-		input_mt_report_slot_state(input, MT_TOOL_FINGER,
-			s->touch_state || s->inrange_state);
-		if (s->touch_state || s->inrange_state) {
+		input_mt_report_slot_state(input, MT_TOOL_FINGER, active);
+		if (active) {
 			/* this finger is in proximity of the sensor */
 			int wide = (s->w > s->h);
 			/* divided by two to match visual scale of touch */

@@ -696,6 +706,8 @@ static void mt_process_mt_event(struct h
 			td->curdata.touch_state = value;
 			break;
 		case HID_DG_CONFIDENCE:
+			if (quirks & MT_QUIRK_CONFIDENCE)
+				td->curdata.confidence_state = value;
 			if (quirks & MT_QUIRK_VALID_IS_CONFIDENCE)
 				td->curvalid = value;
 			break;