[PATCH 4.4 055/146] HID: multitouch: enable palm rejection for Windows Precision Touchpad

Greg Kroah-Hartman
2016-07-25T22:34:57Z

From: Allen Hung <allen_hung@dell.com>

commit 6dd2e27a103d716921cc4a1a96a9adc0a8e3ab57 upstream.

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

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Andy Lutomirski <luto@kernel.org> # XPS 13 9350, BIOS 1.4.3
Signed-off-by: Allen Hung <allen_hung@dell.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/hid/hid-multitouch.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)

--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -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;