Decode mouse dz event

diff -r 69d413abd6c0 drivers/xen/fbfront/xenkbd.c
@@ -64,8 +64,13 @@ static irqreturn_t input_handler(int rq,
 		dev = info->ptr;
 		switch (event->type) {
 		case XENKBD_TYPE_MOTION:
-			input_report_rel(dev, REL_X, event->motion.rel_x);
-			input_report_rel(dev, REL_Y, event->motion.rel_y);
+			if ( event->motion.rel_z == 1 || event->motion.rel_z == -1 ) {
+				input_report_rel(dev, REL_WHEEL, 0 - event->motion.rel_z);
+			}           
+			else {
+				input_report_rel(dev, REL_X, event->motion.rel_x);
+				input_report_rel(dev, REL_Y, event->motion.rel_y);
+			}
 			break;
 		case XENKBD_TYPE_KEY:
 			dev = NULL;

@@ -81,8 +86,13 @@ static irqreturn_t input_handler(int rq,
 				       event->key.keycode);
 			break;
 		case XENKBD_TYPE_POS:
-			input_report_abs(dev, ABS_X, event->pos.abs_x);
-			input_report_abs(dev, ABS_Y, event->pos.abs_y);
+			if ( event->pos.abs_z == 1 || event->pos.abs_z == -1 ) {
+				input_report_rel(dev, REL_WHEEL, 0 - event->pos.abs_z);
+			}
+			else {
+				input_report_abs(dev, ABS_X, event->pos.abs_x);
+				input_report_abs(dev, ABS_Y, event->pos.abs_y);
+			}
 			break;
 		}
 		if (dev)

@@ -152,7 +162,7 @@ int __devinit xenkbd_probe(struct xenbus
 	ptr->evbit[0] = BIT(EV_KEY) | BIT(EV_REL) | BIT(EV_ABS);
 	for (i = BTN_LEFT; i <= BTN_TASK; i++)
 		set_bit(i, ptr->keybit);
-	ptr->relbit[0] = BIT(REL_X) | BIT(REL_Y);
+	ptr->relbit[0] = BIT(REL_X) | BIT(REL_Y) | BIT(REL_WHEEL);
 	input_set_abs_params(ptr, ABS_X, 0, XENFB_WIDTH, 0, 0);
 	input_set_abs_params(ptr, ABS_Y, 0, XENFB_HEIGHT, 0, 0);