Merge branch 'for-4.1/upstream' into for-next

[karo-tx-linux.git] / drivers / input / input-mt.c

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index f4b58f77c524a5188146dd02ba2727354ed1412b..34feb3e1127b2b64c31e8d803f98fcb5ec2aaffc 100644 (file)
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -296,7 +296,7 @@ void input_mt_sync_frame(struct input_dev *dev)
 }
 EXPORT_SYMBOL(input_mt_sync_frame);
 
-static int adjust_dual(int *begin, int step, int *end, int eq)
+static int adjust_dual(int *begin, int step, int *end, int eq, int mu)
 {
        int f, *p, s, c;
 
@@ -314,9 +314,10 @@ static int adjust_dual(int *begin, int step, int *end, int eq)
                        s = *p;
 
        c = (f + s + 1) / 2;
-       if (c == 0 || (c > 0 && !eq))
+       if (c == 0 || (c > mu && (!eq || mu > 0)))
                return 0;
-       if (s < 0)
+       /* Improve convergence for positive matrices by penalizing overcovers */
+       if (s < 0 && mu <= 0)
                c *= 2;
 
        for (p = begin; p != end; p += step)
@@ -325,23 +326,24 @@ static int adjust_dual(int *begin, int step, int *end, int eq)
        return (c < s && s <= 0) || (f >= 0 && f < c);
 }
 
-static void find_reduced_matrix(int *w, int nr, int nc, int nrc)
+static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu)
 {
        int i, k, sum;
 
        for (k = 0; k < nrc; k++) {
                for (i = 0; i < nr; i++)
-                       adjust_dual(w + i, nr, w + i + nrc, nr <= nc);
+                       adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu);
                sum = 0;
                for (i = 0; i < nrc; i += nr)
-                       sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr);
+                       sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);
                if (!sum)
                        break;
        }
 }
 
 static int input_mt_set_matrix(struct input_mt *mt,
-                              const struct input_mt_pos *pos, int num_pos)
+                              const struct input_mt_pos *pos, int num_pos,
+                              int mu)
 {
        const struct input_mt_pos *p;
        struct input_mt_slot *s;
@@ -355,7 +357,7 @@ static int input_mt_set_matrix(struct input_mt *mt,
                y = input_mt_get_value(s, ABS_MT_POSITION_Y);
                for (p = pos; p != pos + num_pos; p++) {
                        int dx = x - p->x, dy = y - p->y;
-                       *w++ = dx * dx + dy * dy;
+                       *w++ = dx * dx + dy * dy - mu;
                }
        }
 
@@ -396,17 +398,24 @@ static void input_mt_set_slots(struct input_mt *mt,
  * @slots: the slot assignment to be filled
  * @pos: the position array to match
  * @num_pos: number of positions
+ * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite)
  *
  * Performs a best match against the current contacts and returns
  * the slot assignment list. New contacts are assigned to unused
  * slots.
  *
+ * The assignments are balanced so that all coordinate displacements are
+ * below the euclidian distance dmax. If no such assignment can be found,
+ * some contacts are assigned to unused slots.
+ *
  * Returns zero on success, or negative error in case of failure.
  */
 int input_mt_assign_slots(struct input_dev *dev, int *slots,
-                         const struct input_mt_pos *pos, int num_pos)
+                         const struct input_mt_pos *pos, int num_pos,
+                         int dmax)
 {
        struct input_mt *mt = dev->mt;
+       int mu = 2 * dmax * dmax;
        int nrc;
 
        if (!mt || !mt->red)
@@ -416,8 +425,8 @@ int input_mt_assign_slots(struct input_dev *dev, int *slots,
        if (num_pos < 1)
                return 0;
 
-       nrc = input_mt_set_matrix(mt, pos, num_pos);
-       find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc);
+       nrc = input_mt_set_matrix(mt, pos, num_pos, mu);
+       find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu);
        input_mt_set_slots(mt, slots, num_pos);
 
        return 0;