From 7091c443dda8c6c6d8e70e33452252f9ad3e7814 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Thu, 18 Dec 2014 09:53:34 -0800 Subject: Input: alps - v7: sometimes a single touch is reported in mt[1] The v7 proto differentiates between a primary touch (with high precision) and a secondary touch (with lower precision). Normally when 2 fingers are down and one is lifted the still present touch becomes the primary touch, but some traces have shown that this does not happen always. This commit deals with this by making alps_get_mt_count() not stop at the first empty mt slot, and if a touch is present in mt[1] and not mt[0] moving the data to mt[0] (for input_mt_assign_slots). BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=86338 Cc: stable@vger.kernel.org # 3.17 Signed-off-by: Hans de Goede Tested-by: Benjamin Tissoires Signed-off-by: Dmitry Torokhov --- drivers/input/mouse/alps.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'drivers/input') diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c index 49e62201bb6b..bfa62a63942f 100644 --- a/drivers/input/mouse/alps.c +++ b/drivers/input/mouse/alps.c @@ -919,12 +919,14 @@ static void alps_get_finger_coordinate_v7(struct input_mt_pos *mt, static int alps_get_mt_count(struct input_mt_pos *mt) { - int i; + int i, fingers = 0; - for (i = 0; i < MAX_TOUCHES && mt[i].x != 0 && mt[i].y != 0; i++) - /* empty */; + for (i = 0; i < MAX_TOUCHES; i++) { + if (mt[i].x != 0 || mt[i].y != 0) + fingers++; + } - return i; + return fingers; } static int alps_decode_packet_v7(struct alps_fields *f, @@ -970,6 +972,14 @@ static int alps_decode_packet_v7(struct alps_fields *f, else /* pkt_id == V7_PACKET_ID_MULTI */ f->fingers = 3 + (p[5] & 0x03); + /* Sometimes a single touch is reported in mt[1] rather then mt[0] */ + if (f->fingers == 1 && f->mt[0].x == 0 && f->mt[0].y == 0) { + f->mt[0].x = f->mt[1].x; + f->mt[0].y = f->mt[1].y; + f->mt[1].x = 0; + f->mt[1].y = 0; + } + return 0; } -- cgit v1.2.3