[PATCH] fix jumpy mouse cursor on console

Do not send empty events to gpm.  (Keyboards are assumed to have scroll
wheel these days, that makes them part-mouse.  That means typing on
keyboard generates empty mouse events).

From: Dmitry Torokhov <dtor_core@ameritech.net>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/input/mousedev.c

@@ -101,6 +101,7 @@ struct mousedev_list {
 	unsigned char ready, buffer, bufsiz;
 	unsigned char imexseq, impsseq;
 	enum mousedev_emul mode;
+	unsigned long last_buttons;
 };
 
 #define MOUSEDEV_SEQ_LEN	6
@@ -224,7 +225,7 @@ static void mousedev_notify_readers(struct mousedev *mousedev, struct mousedev_h
 		spin_lock_irqsave(&list->packet_lock, flags);
 
 		p = &list->packets[list->head];
-		if (list->ready && p->buttons != packet->buttons) {
+		if (list->ready && p->buttons != mousedev->packet.buttons) {
 			unsigned int new_head = (list->head + 1) % PACKET_QUEUE_LEN;
 			if (new_head != list->tail) {
 				p = &list->packets[list->head = new_head];
@@ -249,9 +250,12 @@ static void mousedev_notify_readers(struct mousedev *mousedev, struct mousedev_h
 		p->dz += packet->dz;
 		p->buttons = mousedev->packet.buttons;
 
+		if (p->dx || p->dy || p->dz || p->buttons != list->last_buttons)
 			list->ready = 1;
 
 		spin_unlock_irqrestore(&list->packet_lock, flags);
+
+		if (list->ready)
 			kill_fasync(&list->fasync, SIGIO, POLL_IN);
 	}
 
@@ -477,9 +481,10 @@ static void mousedev_packet(struct mousedev_list *list, signed char *ps2_data)
 	}
 
 	if (!p->dx && !p->dy && !p->dz) {
-		if (list->tail == list->head)
+		if (list->tail == list->head) {
 			list->ready = 0;
-		else
+			list->last_buttons = p->buttons;
+		} else
 			list->tail = (list->tail + 1) % PACKET_QUEUE_LEN;
 	}