Commit 6dd2e27a authored by Allen Hung's avatar Allen Hung Committed by Jiri Kosina
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HID: multitouch: enable palm rejection for Windows Precision Touchpad 



The usage Confidence is mandary to Windows Precision Touchpad devices. If
it is examined in input_mapping on a WIndows Precision Touchpad, a new add
quirk MT_QUIRK_CONFIDENCE desgned for such devices will be applied to the
device. A touch with the confidence bit is not set is determined as
invalid.

Tested on Dell XPS13 9343

Cc: stable@vger.kernel.org # v4.5+
Reviewed-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Andy Lutomirski <luto@kernel.org> # XPS 13 9350, BIOS 1.4.3
Signed-off-by: default avatarAllen Hung <allen_hung@dell.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 62630ea7

drivers/hid/hid-multitouch.c

+15 −3
Original line number Diff line number Diff line
@@ -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 hid_device *hdev, struct hid_input *hi, 
			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_device *td, struct input_dev *input) 
		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_device *td, struct input_dev *input) 
				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 hid_device *hid, struct hid_field *field, 
			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;

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