[PATCH 1/2] Input: elantech - fix V4 report decoding for module with middle key

[Aaron Ma]

From: ??? <kt.liao at emc.com.tw>

BugLink: https://bugs.launchpad.net/bugs/1779802

Some touchpad has middle key and it will be indicated in bit 2 of packet[0].
We need to fix V4 formation's byte mask to prevent error decoding.

Signed-off-by: KT Liao <kt.liao at emc.com.tw>
Cc: stable at vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov at gmail.com>
(cherry picked from commit e0ae2519ca004a628fa55aeef969c37edce522d3)
Signed-off-by: Aaron Ma <aaron.ma at canonical.com>
---
 drivers/input/mouse/elantech.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index a4aaa748e987..a4f18d5cc88d 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -804,7 +804,7 @@ static int elantech_packet_check_v4(struct psmouse *psmouse)
 	else if (ic_version == 7 && etd->samples[1] == 0x2A)
 		sanity_check = ((packet[3] & 0x1c) == 0x10);
 	else
-		sanity_check = ((packet[0] & 0x0c) == 0x04 &&
+		sanity_check = ((packet[0] & 0x08) == 0x00 &&
 				(packet[3] & 0x1c) == 0x10);
 
 	if (!sanity_check)
-- 
2.17.1