Setup pointer acceleration for synaptics

Setup dix pointer accel from the synaptics driver so synaptics devices
behave like before while benefiting from dix velocity approximation.

This fixes the longstanding issue with synaptics being
accelerated twice with different algorithms. The pressure-dependent
synaptics acceleration is now performed in a device-specific profile.

Signed-off-by: Simon Thum <simon.thum@gmx.de>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 88 insertions, 35 deletions

diff --git a/src/synaptics.c b/src/synaptics.c
index 589d04a..ff3c945 100644
--- a/src/synaptics.c
+++ b/src/synaptics.c
@@ -80,6 +80,7 @@
 #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) >= 7
 #include <X11/Xatom.h>
 #include <xserver-properties.h>
+#include <ptrveloc.h>
 #endif
 
 typedef enum {
@@ -546,6 +547,45 @@ static void set_default_parameters(LocalDevicePtr local)
     }
 }
 
+static float SynapticsAccelerationProfile
+    (DeviceIntPtr dev,
+     DeviceVelocityPtr vel,
+     float velocity,
+     float thr,
+     float acc) {
+    LocalDevicePtr local = (LocalDevicePtr) dev->public.devicePrivate;
+    SynapticsPrivate *priv = (SynapticsPrivate *) (local->private);
+    SynapticsParameters* para = &priv->synpara;
+
+    double accelfct;
+
+    /* speed up linear with finger velocity */
+    accelfct = velocity * para->accl;
+
+    /* clip acceleration factor */
+    if (accelfct > para->max_speed)
+	accelfct = para->max_speed;
+    else if (accelfct < para->min_speed)
+	accelfct = para->min_speed;
+
+    /* modify speed according to pressure */
+    if (priv->moving_state == MS_TOUCHPAD_RELATIVE) {
+	int minZ = para->press_motion_min_z;
+	int maxZ = para->press_motion_max_z;
+	double minFctr = para->press_motion_min_factor;
+	double maxFctr = para->press_motion_max_factor;
+	if (priv->hwState.z <= minZ) {
+	    accelfct *= minFctr;
+	} else if (priv->hwState.z >= maxZ) {
+	    accelfct *= maxFctr;
+	} else {
+	    accelfct *= minFctr + (priv->hwState.z - minZ) * (maxFctr - minFctr) / (maxZ - minZ);
+	}
+    }
+
+    return accelfct;
+}
+
 /*
  *  called by the module loader for initialization
  */
@@ -855,12 +895,15 @@ DeviceInit(DeviceIntPtr dev)
 {
     LocalDevicePtr local = (LocalDevicePtr) dev->public.devicePrivate;
     SynapticsPrivate *priv = (SynapticsPrivate *) (local->private);
+    Atom float_type, prop;
+    float tmpf;
     unsigned char map[SYN_MAX_BUTTONS + 1];
     int i;
     int min, max;
 #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) >= 7
     Atom btn_labels[SYN_MAX_BUTTONS] = { 0 };
     Atom axes_labels[2] = { 0 };
+    DeviceVelocityPtr pVel;
 
     InitAxesLabels(axes_labels, 2);
     InitButtonLabels(btn_labels, SYN_MAX_BUTTONS);
@@ -893,6 +936,46 @@ DeviceInit(DeviceIntPtr dev)
                             , axes_labels
 #endif
 			    );
+
+    /*
+     * setup dix acceleration to match legacy synaptics settings, and
+     * etablish a device-specific profile to do stuff like pressure-related
+     * acceleration.
+     */
+#if GET_ABI_MAJOR(ABI_XINPUT_VERSION) >= 7
+    if (NULL != (pVel = GetDevicePredictableAccelData(dev))) {
+	SetDeviceSpecificAccelerationProfile(pVel, SynapticsAccelerationProfile);
+
+	/* float property type */
+	float_type = XIGetKnownProperty(XATOM_FLOAT);
+
+	/* translate MinAcc to constant deceleration.
+	 * May be overridden in xf86IVD */
+	tmpf = 1.0 / priv->synpara.min_speed;
+
+	xf86Msg(X_CONFIG, "%s: (accel) MinSpeed is now constant deceleration %.1f\n",
+	        dev->name, tmpf);
+	prop = XIGetKnownProperty(ACCEL_PROP_CONSTANT_DECELERATION);
+	XIChangeDeviceProperty(dev, prop, float_type, 32,
+	                       PropModeReplace, 1, &tmpf, FALSE);
+
+	/* adjust accordingly */
+	priv->synpara.max_speed /= priv->synpara.min_speed;
+	/* leave priv->synpara.accl alone since velocity includes const decel */
+	priv->synpara.min_speed = 1.0;
+
+	xf86Msg(X_CONFIG, "%s: MaxSpeed is now %.1f\n",
+		dev->name, priv->synpara.max_speed);
+	xf86Msg(X_CONFIG, "%s: AccelFactor is now %.1f\n",
+		dev->name, priv->synpara.accl);
+
+	prop = XIGetKnownProperty(ACCEL_PROP_PROFILE_NUMBER);
+	i = AccelProfileDeviceSpecific;
+	XIChangeDeviceProperty(dev, prop, XA_INTEGER, 32,
+	                       PropModeReplace, 1, &i, FALSE);
+    }
+#endif
+
     /* X valuator */
     if (priv->minx < priv->maxx)
     {
@@ -944,11 +1027,6 @@ DeviceInit(DeviceIntPtr dev)
     return Success;
 }
 
-static int
-move_distance(int dx, int dy)
-{
-    return sqrt(SQR(dx) + SQR(dy));
-}
 
 /*
  * Convert from absolute X/Y coordinates to a coordinate system where
@@ -1589,9 +1667,8 @@ ComputeDeltas(SynapticsPrivate *priv, const struct SynapticsHwState *hw,
 {
     SynapticsParameters *para = &priv->synpara;
     enum MovingState moving_state;
-    int dist;
     double dx, dy;
-    double speed, integral;
+    double integral;
     int delay = 1000000000;
 
     dx = dy = 0;
@@ -1672,36 +1749,12 @@ ComputeDeltas(SynapticsPrivate *priv, const struct SynapticsHwState *hw,
 		}
 	    }
 
-	    /* speed depending on distance/packet */
-	    dist = move_distance(dx, dy);
-	    speed = dist * para->accl;
-	    if (speed > para->max_speed) {  /* set max speed factor */
-		speed = para->max_speed;
-	    } else if (speed < para->min_speed) { /* set min speed factor */
-		speed = para->min_speed;
-	    }
-
-	    /* modify speed according to pressure */
-	    if (priv->moving_state == MS_TOUCHPAD_RELATIVE) {
-		int minZ = para->press_motion_min_z;
-		int maxZ = para->press_motion_max_z;
-		double minFctr = para->press_motion_min_factor;
-		double maxFctr = para->press_motion_max_factor;
-
-		if (hw->z <= minZ) {
-		    speed *= minFctr;
-		} else if (hw->z >= maxZ) {
-		    speed *= maxFctr;
-		} else {
-		    speed *= minFctr + (hw->z - minZ) * (maxFctr - minFctr) / (maxZ - minZ);
-		}
-	    }
-
-	    /* save the fraction, report the integer part */
-	    tmpf = dx * speed + x_edge_speed * dtime + priv->frac_x;
+	    /* report edge speed as synthetic motion. Of course, it would be
+	     * cooler to report floats than to buffer, but anyway. */
+	    tmpf = dx + x_edge_speed * dtime + priv->frac_x;
 	    priv->frac_x = modf(tmpf, &integral);
 	    dx = integral;
-	    tmpf = dy * speed + y_edge_speed * dtime + priv->frac_y;
+	    tmpf = dy + y_edge_speed * dtime + priv->frac_y;
 	    priv->frac_y = modf(tmpf, &integral);
 	    dy = integral;
 	}