Add configurable x/y resolution to fix sensitivity on wide touchpads.

Synaptics uses anisotropic coordinate system.  On some wide touchpads
vertical resolution can be twice as high as horizontal which causes
unequal sensitivity on x/y directions.

VertResolution and HorizResolution can be used to set the resolution.
The ratio of the values is used to compensate x/y sensitivity.  The
properties are configured automatically if touchpad reports resolution
and if running on linux 2.6.31 or newer.

Fixes xorg bug #18351.

Signed-off-by: Tero Saarni <tero.saarni@gmail.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

include/synaptics-properties.h

@@ -149,4 +149,7 @@
  * has_double, has_triple */
 #define SYNAPTICS_PROP_CAPABILITIES "Synaptics Capabilities"
 
+/* 32 bit unsigned, 2 values, vertical, horizontal in units/millimeter */
+#define SYNAPTICS_PROP_RESOLUTION "Synaptics Pad Resolution"
+
 #endif /* _SYNAPTICS_PROPERTIES_H_ */

man/synaptics.man

@@ -425,6 +425,23 @@ touching again and moving the finger on the touchpad.
 The gesture is enabled by default and can be disabled by setting the
 TapAndDragGesture option to false. Property: "Synaptics Gestures"
 .
+.TP
+.BI "Option \*qVertResolution\*q \*q" integer \*q
+Resolution of X coordinates in units/millimeter. The value is used
+together with HorizResolution to compensate unequal vertical and
+horizontal sensitivity. Setting VertResolution and HorizResolution
+equal values means no compensation. Default value is read from
+the touchpad or set to 1 if value could not be read.
+Property: "Synaptics Pad Resolution"
+.
+.TP
+.BI "Option \*qHorizResolution\*q \*q" integer \*q
+Resolution of Y coordinates in units/millimeter. The value is used
+together with VertResolution to compensate unequal vertical and
+horizontal sensitivity. Setting VertResolution and HorizResolution
+equal values means no compensation. Default value is read from
+the touchpad or set to 1 if value could not be read.
+Property: "Synaptics Pad Resolution"
 .LP
 The LeftEdge, RightEdge, TopEdge and BottomEdge parameters are used to
 define the edge and corner areas of the touchpad.
@@ -812,6 +829,10 @@ scrolling.
 8 bit (BOOL), 5 values (read-only), has left button, has middle button, has
 right button, two-finger detection, three-finger detection.
 
+.TP 7
+.BI "Synaptics Pad Resolution"
+32 bit unsigned, 2 values (read-only), vertical, horizontal in units/millimeter.
+
 .SH "NOTES"
 There is an example hal policy file in
 .I ${sourcecode}/fdi/11-x11-synaptics.fdi
@@ -827,8 +848,8 @@ If either of
 (default) or
 .BI "Protocol \*q" event \*q
 is used, the driver initializes defaults based on the capabilities reported by
-the kernel driver. Acceleration and edges are based on the dimensions reported
-by the kernel. If the kernel reports multi-finger detection, two-finger
+the kernel driver. Acceleration, edges and resolution are based on the dimensions
+reported by the kernel. If the kernel reports multi-finger detection, two-finger
 vertical scrolling is enabled, horizontal two-finger scrolling is disabled and
 edge scrolling is disabled. If no multi-finger capabilities are reported,
 edge scrolling is enabled for both horizontal and vertical scrolling.

src/eventcomm.c

@@ -171,7 +171,7 @@ static void
 event_query_axis_ranges(LocalDevicePtr local)
 {
     SynapticsPrivate *priv = (SynapticsPrivate *)local->private;
-    struct input_absinfo abs;
+    struct input_absinfo abs = {0};
     unsigned long absbits[NBITS(ABS_MAX)] = {0};
     unsigned long keybits[NBITS(KEY_MAX)] = {0};
     char buf[256];
@@ -184,6 +184,9 @@ event_query_axis_ranges(LocalDevicePtr local)
 		abs.minimum, abs.maximum);
 	priv->minx = abs.minimum;
 	priv->maxx = abs.maximum;
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,30)
+	priv->resx = abs.resolution;
+#endif
     } else
 	xf86Msg(X_ERROR, "%s: failed to query axis range (%s)\n", local->name,
 		strerror(errno));
@@ -195,6 +198,9 @@ event_query_axis_ranges(LocalDevicePtr local)
 		abs.minimum, abs.maximum);
 	priv->miny = abs.minimum;
 	priv->maxy = abs.maximum;
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,30)
+	priv->resy = abs.resolution;
+#endif
     } else
 	xf86Msg(X_ERROR, "%s: failed to query axis range (%s)\n", local->name,
 		strerror(errno));

src/eventcomm.h

@@ -28,6 +28,7 @@
 #define _EVENTCOMM_H_
 
 #include <linux/input.h>
+#include <linux/version.h>
 
 /* for auto-dev: */
 #define DEV_INPUT_EVENT "/dev/input"

src/properties.c

@@ -82,6 +82,7 @@ Atom prop_pressuremotion_factor = 0;
 Atom prop_grab                  = 0;
 Atom prop_gestures              = 0;
 Atom prop_capabilities          = 0;
+Atom prop_resolution            = 0;
 
 static Atom
 InitAtom(DeviceIntPtr dev, char *name, int format, int nvalues, int *values)
@@ -262,6 +263,11 @@ InitDeviceProperties(LocalDevicePtr local)
     values[3] = priv->has_double;
     values[4] = priv->has_triple;
     prop_capabilities = InitAtom(local->dev, SYNAPTICS_PROP_CAPABILITIES, 8, 5, values);
+
+    values[0] = para->resolution_vert;
+    values[1] = para->resolution_horiz;
+    prop_resolution = InitAtom(local->dev, SYNAPTICS_PROP_RESOLUTION, 32, 2, values);
+
 }
 
 int
@@ -609,6 +615,10 @@ SetProperty(DeviceIntPtr dev, Atom property, XIPropertyValuePtr prop,
 
         para->grab_event_device = *(BOOL*)prop->data;
     } else if (property == prop_capabilities)
+    {
+        /* read-only */
+        return BadValue;
+    } else if (property == prop_resolution)
     {
         /* read-only */
         return BadValue;

src/synaptics.c

@@ -118,6 +118,8 @@ static Bool DeviceOff(DeviceIntPtr);
 static Bool DeviceClose(DeviceIntPtr);
 static Bool QueryHardware(LocalDevicePtr);
 static void ReadDevDimensions(LocalDevicePtr);
+static void ScaleCoordinates(SynapticsPrivate *priv, struct SynapticsHwState *hw);
+static void CalculateScalingCoeffs(SynapticsPrivate *priv);
 
 #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) >= 3
 void InitDeviceProperties(LocalDevicePtr local);
@@ -338,6 +340,8 @@ static void set_default_parameters(LocalDevicePtr local)
     int clickFinger1, clickFinger2, clickFinger3;
     Bool vertEdgeScroll, horizEdgeScroll;
     Bool vertTwoFingerScroll, horizTwoFingerScroll;
+    int horizResolution = 1;
+    int vertResolution = 1;
 
     /* read the parameters */
     if (priv->synshm)
@@ -439,6 +443,12 @@ static void set_default_parameters(LocalDevicePtr local)
     vertTwoFingerScroll = priv->has_double ? TRUE : FALSE;
     horizTwoFingerScroll = FALSE;
 
+    /* Use resolution reported by hardware if available */
+    if ((priv->resx > 0) && (priv->resy > 0)) {
+        horizResolution = priv->resx;
+        vertResolution = priv->resy;
+    }
+
     /* set the parameters */
     priv->edges_forced = 0;
     if (xf86CheckIfOptionUsedByName(opts, "LeftEdge"))
@@ -517,6 +527,8 @@ static void set_default_parameters(LocalDevicePtr local)
     pars->press_motion_max_factor = xf86SetRealOption(opts, "PressureMotionMaxFactor", 1.0);
     pars->grab_event_device = xf86SetBoolOption(opts, "GrabEventDevice", TRUE);
     pars->tap_and_drag_gesture = xf86SetBoolOption(opts, "TapAndDragGesture", TRUE);
+    pars->resolution_horiz = xf86SetIntOption(opts, "HorizResolution", horizResolution);
+    pars->resolution_vert = xf86SetIntOption(opts, "VertResolution", vertResolution);
 
     /* Warn about (and fix) incorrectly configured TopEdge/BottomEdge parameters */
     if (pars->top_edge > pars->bottom_edge) {
@@ -619,6 +631,8 @@ SynapticsPreInit(InputDriverPtr drv, IDevPtr dev, int flags)
 
     set_default_parameters(local);
 
+    CalculateScalingCoeffs(priv);
+
     if (!alloc_param_data(local))
 	goto SetupProc_fail;
 
@@ -905,7 +919,7 @@ DeviceInit(DeviceIntPtr dev)
 #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) >= 7
             axes_labels[0],
 #endif
-            min, max, 1, 0, 1);
+            min, max, priv->resx * 1000, 0, priv->resx * 1000);
     xf86InitValuatorDefaults(dev, 0);
 
     /* Y valuator */
@@ -923,7 +937,7 @@ DeviceInit(DeviceIntPtr dev)
 #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) >= 7
             axes_labels[1],
 #endif
-            min, max, 1, 0, 1);
+            min, max, priv->resy * 1000, 0, priv->resy * 1000);
     xf86InitValuatorDefaults(dev, 1);
 
 #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) == 0
@@ -2229,6 +2243,13 @@ HandleState(LocalDevicePtr local, struct SynapticsHwState *hw)
     if (timeleft > 0)
 	delay = MIN(delay, timeleft);
 
+    /*
+     * Compensate for unequal x/y resolution. This needs to be done after
+     * calculations that require unadjusted coordinates, for example edge
+     * detection.
+     */
+    ScaleCoordinates(priv, hw);
+
     timeleft = ComputeDeltas(priv, hw, edge, &dx, &dy);
     delay = MIN(delay, timeleft);
 
@@ -2414,3 +2435,30 @@ QueryHardware(LocalDevicePtr local)
     return TRUE;
 }
 
+static void
+ScaleCoordinates(SynapticsPrivate *priv, struct SynapticsHwState *hw)
+{
+    int xCenter = (priv->synpara.left_edge + priv->synpara.right_edge) / 2;
+    int yCenter = (priv->synpara.top_edge + priv->synpara.bottom_edge) / 2;
+
+    hw->x = (hw->x - xCenter) * priv->horiz_coeff + xCenter;
+    hw->y = (hw->y - yCenter) * priv->vert_coeff + yCenter;
+}
+
+void
+CalculateScalingCoeffs(SynapticsPrivate *priv)
+{
+    int vertRes = priv->synpara.resolution_vert;
+    int horizRes = priv->synpara.resolution_horiz;
+
+    if ((horizRes > vertRes) && (horizRes > 0)) {
+        priv->horiz_coeff = vertRes / (double)horizRes;
+        priv->vert_coeff = 1;
+    } else if ((horizRes < vertRes) && (vertRes > 0)) {
+        priv->horiz_coeff = 1;
+        priv->vert_coeff = horizRes / (double)vertRes;
+    } else {
+        priv->horiz_coeff = 1;
+        priv->vert_coeff = 1;
+    }
+}

src/synapticsstr.h

@@ -164,6 +164,8 @@ typedef struct _SynapticsParameters
     double press_motion_max_factor; 	    /* factor applied on speed when finger pressure is at minimum */
     Bool grab_event_device;		    /* grab event device for exclusive use? */
     Bool tap_and_drag_gesture;		    /* Switches the tap-and-drag gesture on/off */
+    unsigned int resolution_horiz;          /* horizontal resolution of touchpad in units/mm */
+    unsigned int resolution_vert;           /* vertical resolution of touchpad in units/mm */
 } SynapticsParameters;
 
 
@@ -224,9 +226,12 @@ typedef struct _SynapticsPrivateRec
 					   palm/finger contact disappears */
     int prev_z;				/* previous z value, for palm detection */
     int avg_width;			/* weighted average of previous fingerWidth values */
+    double horiz_coeff;                 /* normalization factor for x coordintes */
+    double vert_coeff;                  /* normalization factor for y coordintes */
 
     int minx, maxx, miny, maxy;         /* min/max dimensions as detected */
     int minp, maxp, minw, maxw;		/* min/max pressure and finger width as detected */
+    int resx, resy;                     /* resolution of coordinates as detected in units/mm */
     Bool has_left;			/* left button detected for this device */
     Bool has_right;			/* right button detected for this device */
     Bool has_middle;			/* middle button detected for this device */