[PATCH 3/4] HID: multitouch: drop reports containing invalid values

From: Joey Pabalinas
Date: Sat Jun 30 2018 - 20:20:32 EST


Avoid processing reports containing invalid values to reduce
multitouch input stutter.

Signed-off-by: Joey Pabalinas <joeypabalinas@xxxxxxxxx>

1 file changed, 9 insertions(+)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index c0654db0b736543ca0..08b50e5908cecdda66 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -694,10 +694,19 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
{
if ((td->mtclass.quirks & MT_QUIRK_CONTACT_CNT_ACCURATE) &&
td->num_received >= td->num_expected)
return;

+ /* drop invalid values after counting them */
+ if (td->curdata.x == 0xffff &&
+ td->curdata.y == 0xffff &&
+ td->curdata.w == 0xffff &&
+ td->curdata.h == 0xffff) {
+ td->num_received++;
+ 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;
--
2.18.0