Input: fix absolute device handling in mousedev that was broken

       by recent change that tried to do better multiplexing.
       Now every client will keep its own virtual cursor position
       and both absolute and relative events will update it
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/mousedev.c

@@ -52,8 +52,10 @@ static unsigned tap_time = 200;
 module_param(tap_time, uint, 0);
 MODULE_PARM_DESC(tap_time, "Tap time for touchpads in absolute mode (msecs)");
 
-struct mousedev_motion {
+struct mousedev_hw_data {
 	int dx, dy, dz;
+	int x, y;
+	int abs_event;
 	unsigned long buttons;
 };
 
@@ -66,7 +68,7 @@ struct mousedev {
 	struct list_head list;
 	struct input_handle handle;
 
-	struct mousedev_motion packet;
+	struct mousedev_hw_data packet;
 	unsigned int pkt_count;
 	int old_x[4], old_y[4];
 	unsigned long touch;
@@ -78,6 +80,11 @@ enum mousedev_emul {
 	MOUSEDEV_EMUL_EXPS
 };
 
+struct mousedev_motion {
+	int dx, dy, dz;
+	unsigned long buttons;
+};
+
 #define PACKET_QUEUE_LEN	16
 struct mousedev_list {
 	struct fasync_struct *fasync;
@@ -87,6 +94,7 @@ struct mousedev_list {
 	struct mousedev_motion packets[PACKET_QUEUE_LEN];
 	unsigned int head, tail;
 	spinlock_t packet_lock;
+	int pos_x, pos_y;
 
 	signed char ps2[6];
 	unsigned char ready, buffer, bufsiz;
@@ -134,15 +142,19 @@ static void mousedev_abs_event(struct input_dev *dev, struct mousedev *mousedev,
 		case ABS_X:
 			size = dev->absmax[ABS_X] - dev->absmin[ABS_X];
 			if (size == 0) size = xres;
-			mousedev->packet.dx = (value * xres - mousedev->old_x[0]) / size;
-			mousedev->old_x[0] = mousedev->packet.dx * size;
+			if (value > dev->absmax[ABS_X]) value = dev->absmax[ABS_X];
+			if (value < dev->absmin[ABS_X]) value = dev->absmin[ABS_X];
+			mousedev->packet.x = ((value - dev->absmin[ABS_X]) * xres) / size;
+			mousedev->packet.abs_event = 1;
 			break;
 
 		case ABS_Y:
 			size = dev->absmax[ABS_Y] - dev->absmin[ABS_Y];
 			if (size == 0) size = yres;
-			mousedev->packet.dy = (value * yres - mousedev->old_y[0]) / size;
-			mousedev->old_y[0] = mousedev->packet.dy * size;
+			if (value > dev->absmax[ABS_Y]) value = dev->absmax[ABS_Y];
+			if (value < dev->absmin[ABS_Y]) value = dev->absmin[ABS_Y];
+			mousedev->packet.y = yres - ((value - dev->absmin[ABS_Y]) * yres) / size;
+			mousedev->packet.abs_event = 1;
 			break;
 	}
 }
@@ -188,7 +200,7 @@ static void mousedev_key_event(struct mousedev *mousedev, unsigned int code, int
 	}
 }
 
-static void mousedev_notify_readers(struct mousedev *mousedev, struct mousedev_motion *packet)
+static void mousedev_notify_readers(struct mousedev *mousedev, struct mousedev_hw_data *packet)
 {
 	struct mousedev_list *list;
 	struct mousedev_motion *p;
@@ -206,6 +218,18 @@ static void mousedev_notify_readers(struct mousedev *mousedev, struct mousedev_m
 			}
 		}
 
+		if (packet->abs_event) {
+			p->dx += packet->x - list->pos_x;
+			p->dy += packet->y - list->pos_y;
+			list->pos_x = packet->x;
+			list->pos_y = packet->y;
+		}
+
+		list->pos_x += packet->dx;
+		list->pos_x = list->pos_x < 0 ? 0 : (list->pos_x >= xres ? xres : list->pos_x);
+		list->pos_y += packet->dy;
+		list->pos_y = list->pos_y < 0 ? 0 : (list->pos_y >= yres ? yres : list->pos_y);
+
 		p->dx += packet->dx;
 		p->dy += packet->dy;
 		p->dz += packet->dz;
@@ -224,7 +248,7 @@ static void mousedev_touchpad_touch(struct mousedev *mousedev, int value)
 {
 	if (!value) {
 		if (mousedev->touch &&
-		    !time_after(jiffies, mousedev->touch + msecs_to_jiffies(tap_time))) {
+		    time_before(jiffies, mousedev->touch + msecs_to_jiffies(tap_time))) {
 			/*
 			 * Toggle left button to emulate tap.
 			 * We rely on the fact that mousedev_mix always has 0
@@ -289,6 +313,7 @@ static void mousedev_event(struct input_handle *handle, unsigned int type, unsig
 				mousedev_notify_readers(&mousedev_mix, &mousedev->packet);
 
 				mousedev->packet.dx = mousedev->packet.dy = mousedev->packet.dz = 0;
+				mousedev->packet.abs_event = 0;
 			}
 			break;
 	}
@@ -374,6 +399,8 @@ static int mousedev_open(struct inode * inode, struct file * file)
 	memset(list, 0, sizeof(struct mousedev_list));
 
 	spin_lock_init(&list->packet_lock);
+	list->pos_x = xres / 2;
+	list->pos_y = yres / 2;
 	list->mousedev = mousedev_table[i];
 	list_add_tail(&list->node, &mousedev_table[i]->list);
 	file->private_data = list;