[PATCH] Input: MT - make slot assignment work for overcovered solutions

[Henrik Rydberg]

The recent inclusion of a deassignment cost in the slot assignment
algorithm did not properly account for the corner cases where the
solutions are overcovered. This patch makes sure the resulting assignment
is unique, allocating new slots when necessary.

UNTESTED
---
 drivers/input/input-mt.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index fbe29fc..17e80a6 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -363,25 +363,28 @@ static void input_mt_set_slots(struct input_mt *mt,
 			       int *slots, int num_pos)
 {
 	struct input_mt_slot *s;
-	int *w = mt->red, *p;
+	int *w = mt->red, j;
 
-	for (p = slots; p != slots + num_pos; p++)
-		*p = -1;
+	for (j = 0; j != num_pos; j++)
+		slots[j] = -1;
 
 	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 		if (!input_mt_is_active(s))
 			continue;
-		for (p = slots; p != slots + num_pos; p++)
-			if (*w++ < 0)
-				*p = s - mt->slots;
+		for (j = 0; j != num_pos; j++)
+			if (w[j] < 0) {
+				slots[j] = s - mt->slots;
+				break;
+			}
+		w += num_pos;
 	}
 
 	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 		if (input_mt_is_active(s))
 			continue;
-		for (p = slots; p != slots + num_pos; p++)
-			if (*p < 0) {
-				*p = s - mt->slots;
+		for (j = 0; j != num_pos; j++)
+			if (slots[j] < 0) {
+				slots[j] = s - mt->slots;
 				break;
 			}
 	}
-- 
2.3.0

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