[PATCH libinput 2/2] touchpad: reduce the tap movement threshold to 1.3mm

[Peter Hutterer]

When a finger moves less than the movement threshold, motion is filtered until
the timeout is hit. If the threshold is too high the responsiveness of the
pointer suffers.

Event analysis from several users showed that 95% of the touches move less
than 1.3mm long. Reducing the threshold should have almost no impact on most
tapping users but improves the reaction time of the pointer for normal
movements.

For a more details see:
http://who-t.blogspot.com/2016/12/libinput-touchpad-tap-analysis.html

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/evdev-mt-touchpad-tap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/evdev-mt-touchpad-tap.c b/src/evdev-mt-touchpad-tap.c
index b65bac4..ffd9d0b 100644
--- a/src/evdev-mt-touchpad-tap.c
+++ b/src/evdev-mt-touchpad-tap.c
@@ -36,7 +36,7 @@
 #define DEFAULT_TAP_INITIAL_TIMEOUT_PERIOD ms2us(100)
 #define DEFAULT_TAP_TIMEOUT_PERIOD ms2us(180)
 #define DEFAULT_DRAG_TIMEOUT_PERIOD ms2us(300)
-#define DEFAULT_TAP_MOVE_THRESHOLD TP_MM_TO_DPI_NORMALIZED(3)
+#define DEFAULT_TAP_MOVE_THRESHOLD TP_MM_TO_DPI_NORMALIZED(1.3)
 
 enum tap_event {
 	TAP_EVENT_TOUCH = 12,
-- 
2.9.3