From 87685a78e83f990705b7eeb5b3afb3045a8da5ce Mon Sep 17 00:00:00 2001

From: Hans de Goede <hdegoede@redhat.com>

Date: Fri, 21 Feb 2014 10:31:44 +0100

Subject: [PATCH synaptics 08/11] Wait for *new* coordinates on a clickpad

 click before reporting the click

It is possible for a click to get reported before any related touch events

get reported, here is the relevant part of an evemu-record session on a T440s:

E: 3.985585 0000 0000 0000	# ------------ SYN_REPORT (0) ----------

E: 3.997419 0003 0039 -001	# EV_ABS / ABS_MT_TRACKING_ID   -1

E: 3.997419 0001 014a 0000	# EV_KEY / BTN_TOUCH            0

E: 3.997419 0003 0018 0000	# EV_ABS / ABS_PRESSURE         0

E: 3.997419 0001 0145 0000	# EV_KEY / BTN_TOOL_FINGER      0

E: 3.997419 0000 0000 0000	# ------------ SYN_REPORT (0) ----------

E: 5.117881 0001 0110 0001	# EV_KEY / BTN_LEFT             1

E: 5.117881 0000 0000 0000	# ------------ SYN_REPORT (0) ----------

E: 5.133422 0003 0039 0187	# EV_ABS / ABS_MT_TRACKING_ID   187

E: 5.133422 0003 0035 3098	# EV_ABS / ABS_MT_POSITION_X    3098

E: 5.133422 0003 0036 3282	# EV_ABS / ABS_MT_POSITION_Y    3282

E: 5.133422 0003 003a 0046	# EV_ABS / ABS_MT_PRESSURE      46

E: 5.133422 0001 014a 0001	# EV_KEY / BTN_TOUCH            1

E: 5.133422 0003 0000 3102	# EV_ABS / ABS_X                3102

E: 5.133422 0003 0001 3282	# EV_ABS / ABS_Y                3282

E: 5.133422 0003 0018 0046	# EV_ABS / ABS_PRESSURE         46

E: 5.133422 0001 0145 0001	# EV_KEY / BTN_TOOL_FINGER      1

E: 5.133422 0000 0000 0000	# ------------ SYN_REPORT (0) ----------

Notice the BTN_LEFT event all by itself!

If this happens, it may lead to the following problem scenario:

-touch the touchpad in its right click area

-let go of the touchpad

-rapidly click in the middle area, so that BTN_LEFT gets reported before the

 new coordinates (such as seen in the trace above, this may require some

 practicing with evemu-record to reproduce)

-the driver registers the click as a right click because it uses the

 old coordinates from the cumulative coordinates to determine the

 click location

This commit fixes this by:

1) Resetting the cumulative coordinates not only when no button is pressed,

   but also when there is no finger touching the touchpad, so that when

   we do get a touch the cumulative coordinates start at the right place

2) Delaying processing the BTN_LEFT down transition if there is no finger

   touching the touchpad

This approach has one downside, if we wrongly identify a touchpad as

a clickpad, then the left button won't work unless the user touches the

touchpad while clicking the left button.

If we want we can fix this by doing something like this:

1) Making update_hw_button_state return a delay; and

2) Tracking that we've delayed BTN_LEFT down transition processing; and

3) When we've delayed BTN_LEFT down transition return a small delay value; and

4) If when we're called again we still don't have a finger down, just

   treat the click as a BTN_LEFT

But this is not worth the trouble IMHO, the proper thing to do in this

scenario is to fix the mis-identification of the touchpad as a clickpad.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

(cherry picked from commit bbe4c56c4998a90b478581a4d93717251d8e05be)

---

 src/eventcomm.c | 5 +++--

 src/synaptics.c | 7 +++++++

 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/eventcomm.c b/src/eventcomm.c

index 8c30991..c5bc7ad 100644

--- a/src/eventcomm.c

+++ b/src/eventcomm.c

@@ -633,8 +633,9 @@ EventReadHwState(InputInfoPtr pInfo,

     SynapticsResetTouchHwState(hw, FALSE);

-    /* Reset cumulative values if buttons were not previously pressed */

-    if (!hw->left && !hw->right && !hw->middle) {

+    /* Reset cumulative values if buttons were not previously pressed,

+     * or no finger was previously present. */

+    if ((!hw->left && !hw->right && !hw->middle) || hw->z < para->finger_low) {

         hw->cumulative_dx = hw->x;

         hw->cumulative_dy = hw->y;

         sync_cumulative = TRUE;

diff --git a/src/synaptics.c b/src/synaptics.c

index 4cd45b6..1170963 100644

--- a/src/synaptics.c

+++ b/src/synaptics.c

@@ -2774,6 +2774,12 @@ update_hw_button_state(const InputInfoPtr pInfo, struct SynapticsHwState *hw,

     if (para->clickpad) {

         /* hw->left is down, but no other buttons were already down */

         if (!(priv->lastButtons & 7) && hw->left && !hw->right && !hw->middle) {

+            /* If the finger down event is delayed, the x and y

+             * coordinates are stale so we delay processing the click */

+            if (hw->z < para->finger_low) {

+                hw->left = 0;

+                goto out;

+            }

             if (is_inside_rightbutton_area(para, hw->x, hw->y)) {

                 hw->left = 0;

                 hw->right = 1;

@@ -2805,6 +2811,7 @@ update_hw_button_state(const InputInfoPtr pInfo, struct SynapticsHwState *hw,

     if (hw->left && !(priv->lastButtons & 7) && hw->numFingers >= 1)

         handle_clickfinger(priv, hw);

+out:

     /* Two finger emulation */

     if (hw->numFingers == 1 && hw->z >= para->emulate_twofinger_z &&

         hw->fingerWidth >= para->emulate_twofinger_w) {

--

1.8.5.3