HID: multitouch: ensure that serial devices make no use of contact count

The serial protocol makes contact count a redondant information, and
sometimes it is not reliable (TRS-Star are in this case).
Disabling the use of contact count for these devices is thus safer.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 1cf676d93049..2693059df534 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -758,6 +758,7 @@ static void mt_post_parse_default_settings(struct mt_device *td)
                 quirks &= ~MT_QUIRK_NOT_SEEN_MEANS_UP;
                 quirks &= ~MT_QUIRK_VALID_IS_INRANGE;
                 quirks &= ~MT_QUIRK_VALID_IS_CONFIDENCE;
+                quirks &= ~MT_QUIRK_CONTACT_CNT_ACCURATE;
         }
 
         td->mtclass.quirks = quirks;