xf86PostTouchEvent back in xf86-input-synaptics-1.8.99.1

xf86-input-synaptics-1.8.99.1.xf86PostTouchEvent.patch

diff -ru xf86-input-synaptics-1.8.99.1/src/synaptics.c xf86-input-synaptics-1.8.99.1-mod/src/synaptics.c
--- xf86-input-synaptics-1.8.99.1/src/synaptics.c	2015-11-25 07:28:43.000000000 +0100
+++ xf86-input-synaptics-1.8.99.1-mod/src/synaptics.c	2016-06-15 14:54:09.961917509 +0200
@@ -1190,7 +1190,8 @@
 {
     InputInfoPtr pInfo = dev->public.devicePrivate;
     SynapticsPrivate *priv = (SynapticsPrivate *) (pInfo->private);
-
+    int i;
+	
     if (!priv->has_touch)
         return;
 
@@ -1204,8 +1205,23 @@
         priv->has_touch = 0;
         priv->num_slots = 0;
     }
+
+	// x/y + whatever other MT axes we found
+	if (!InitTouchClassDeviceStruct(dev, priv->max_touches,
+									XIDependentTouch,
+									2 + priv->num_mt_axes)) {
+		xf86IDrvMsg(pInfo, X_ERROR,
+					"failed to initialize touch class device\n");
+		priv->has_touch = 0;
+		priv->num_slots = 0;
+		free(priv->open_slots);
+		priv->open_slots = NULL;
+		return;
+	}
+    
 }
 
+
 static int
 DeviceInit(DeviceIntPtr dev)
 {
@@ -2979,9 +2995,18 @@
 HandleTouches(InputInfoPtr pInfo, struct SynapticsHwState *hw)
 {
     SynapticsPrivate *priv = (SynapticsPrivate *) pInfo->private;
+    SynapticsParameters *para = &priv->synpara;
     int new_active_touches = priv->num_active_touches;
+    int min_touches = 2;
+    Bool restart_touches = FALSE;
     int i;
 
+    if (para->click_action[F3_CLICK1] || para->tap_action[F3_TAP])
+        min_touches = 4;
+    else if (para->click_action[F2_CLICK1] || para->tap_action[F2_TAP] ||
+             para->scroll_twofinger_vert || para->scroll_twofinger_horiz)
+        min_touches = 3;
+
     /* Count new number of active touches */
     for (i = 0; i < hw->num_mt_mask; i++) {
         if (hw->slot_state[i] == SLOTSTATE_OPEN)
@@ -2990,6 +3015,58 @@
             new_active_touches--;
     }
 
+    if (priv->has_semi_mt)
+        goto out;
+
+    if (priv->num_active_touches < min_touches &&
+        new_active_touches < min_touches) {
+        /* We stayed below number of touches needed to send events */
+        goto out;
+    }
+    else if (priv->num_active_touches >= min_touches &&
+             new_active_touches < min_touches) {
+        /* We are transitioning to less than the number of touches needed to
+         * send events. End all currently open touches. */
+        for (i = 0; i < priv->num_active_touches; i++) {
+            int slot = priv->open_slots[i];
+
+            xf86PostTouchEvent(pInfo->dev, slot, XI_TouchEnd, 0,
+                               hw->mt_mask[slot]);
+        }
+
+        /* Don't send any more events */
+        goto out;
+    }
+    else if (priv->num_active_touches < min_touches &&
+             new_active_touches >= min_touches) {
+        /* We are transitioning to more than the number of touches needed to
+         * send events. Begin all already open touches. */
+        restart_touches = TRUE;
+        for (i = 0; i < priv->num_active_touches; i++) {
+            int slot = priv->open_slots[i];
+
+            xf86PostTouchEvent(pInfo->dev, slot, XI_TouchBegin, 0,
+                               hw->mt_mask[slot]);
+        }
+    }
+    
+    /* Send touch begin events for all new touches */
+    for (i = 0; i < hw->num_mt_mask; i++)
+        if (hw->slot_state[i] == SLOTSTATE_OPEN)
+            xf86PostTouchEvent(pInfo->dev, i, XI_TouchBegin, 0, hw->mt_mask[i]);
+    /* Send touch update/end events for all the rest */
+    for (i = 0; i < priv->num_active_touches; i++) {
+        int slot = priv->open_slots[i];
+
+        /* Don't send update event if we just reopened the touch above */
+        if (hw->slot_state[slot] == SLOTSTATE_UPDATE && !restart_touches)
+            xf86PostTouchEvent(pInfo->dev, slot, XI_TouchUpdate, 0,
+                               hw->mt_mask[slot]);
+        else if (hw->slot_state[slot] == SLOTSTATE_CLOSE)
+            xf86PostTouchEvent(pInfo->dev, slot, XI_TouchEnd, 0,
+                               hw->mt_mask[slot]);
+    }
+out:
     UpdateTouchState(pInfo, hw);
 }

Or if you're having problems applying the patch, you may simply use the older version:

First, some dependencies:
sudo pacman -S autoconf xorg-server-devel xorg-util-macros

git clone git://anongit.freedesktop.org/xorg/driver/xf86-input-synaptics
cd xf86-input-synaptics
git checkout xf86-input-synaptics-1.8.3
./autogen.sh
./configure --prefix=/usr
make
sudo make install

On Arch Linux (probably others too in similar manner) you need to additionally cp /usr/share/X11/xorg.conf.d/50-synaptics.conf /etc/X11/xorg.conf.d/.

I ran into an error using tsusanka's answer, when running "./autogen.sh" it turns out that it needed a package "xorg-macros". After a bit of digging around, I realized that I could use Menci's comment to install them (xutils-dev is the package, if I am not mistaken). In sum, run:

sudo apt install autoconf xutils-dev xorg-dev libtool libevdev-dev

and then:

git clone git://anongit.freedesktop.org/xorg/driver/xf86-input-synaptics
cd xf86-input-synaptics
git checkout xf86-input-synaptics-1.8.3
./autogen.sh
./configure --prefix=/usr
make
sudo make install

touchegg worked after restarting my computer. Enjoy!

@bndr32 is right you need some additional libraries to make it work, on Arch Linux it's (but you may need some more):

sudo pacman -S autoconf xorg-server-devel xorg-util-macros

I've also modified my previous post

curl -OL https://gist.githubusercontent.com/dbruenig/ae80fedbeded12084b7227b0ef53aeec/raw/67d7bdc420b0236610ff51dd8e8e5a44b733ed0c/xf86-input-synaptics-1.8.99.1.xf86PostTouchEvent.patch

link gives a 404

curl -OL https://gist.githubusercontent.com/dbruenig/ae80fedbeded12084b7227b0ef53aeec/raw/67d7bdc420b0236610ff51dd8e8e5a44b733ed0c/xf86-input-synaptics-1.8.99.1.xf86PostTouchEvent.patch

link gives a 404

write these commands instead;

git clone https://gist.github.com/ae80fedbeded12084b7227b0ef53aeec.git
mv ae80fedbeded12084b7227b0ef53aeec/xf86-input-synaptics-1.8.99.1.xf86PostTouchEvent.patch .
sudo rm -r ae80fedbeded12084b7227b0ef53aeec/