+tp_palm_detect(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time)
+{
+ const int PALM_TIMEOUT = 200; /* ms */
+ const int DIRECTIONS = NE|E|SE|SW|W|NW;
+
+ /* If labelled a touch as palm, we unlabel as palm when
+ we move out of the palm edge zone within the timeout, provided
+ the direction is within 45 degrees of the horizontal.
+ */
+ if (t->palm.is_palm) {
+ if (time < t->palm.time + PALM_TIMEOUT &&
+ (t->x > tp->palm.left_edge && t->x < tp->palm.right_edge)) {
+ int dirs = vector_get_direction(t->x - t->palm.x, t->y - t->palm.y);
+ if ((dirs & DIRECTIONS) && !(dirs & ~DIRECTIONS)) {
+ t->palm.is_palm = false;
+ tp_set_pointer(tp, t);
+ }
+ }
+ return;
+ }
+
+ /* palm must start in exclusion zone, it's ok to move into
+ the zone without being a palm */
+ if (t->state != TOUCH_BEGIN ||
+ (t->x > tp->palm.left_edge && t->x < tp->palm.right_edge))
+ return;
+
+ /* don't detect palm in software button areas, it's
+ likely that legitimate touches start in the area
+ covered by the exclusion zone */
+ if (tp->buttons.is_clickpad &&
+ tp_button_is_inside_softbutton_area(tp, t))
+ return;
+
+ t->palm.is_palm = true;
+ t->palm.time = time;
+ t->palm.x = t->x;
+ t->palm.y = t->y;
+}
+
+static void