HID: multitouch: fix Win8 protocol for Sharp like devices

The Sharp LC-20FE1-W screen (04dd:9681) behaves like the Nexio 42".
It may report out of ranges values that are filtered out by relying
on the Contact Count HID field.
Adding the quirk MT_QUIRK_CONTACT_CNT_ACCURATE makes hid-multitouch
strongest against this kind of device, without breaking the current
devices.

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

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 87690e2726ac3318963e65b3bf65066ef4c25543..1cf676d93049de001d56bcf6696ff2742a60c652 100644 (file)
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -311,6 +311,7 @@ static void mt_feature_mapping(struct hid_device *hdev,
                        *quirks |= MT_QUIRK_ALWAYS_VALID;
                        *quirks |= MT_QUIRK_IGNORE_DUPLICATES;
                        *quirks |= MT_QUIRK_HOVERING;
+                       *quirks |= MT_QUIRK_CONTACT_CNT_ACCURATE;
                        *quirks &= ~MT_QUIRK_NOT_SEEN_MEANS_UP;
                        *quirks &= ~MT_QUIRK_VALID_IS_INRANGE;
                        *quirks &= ~MT_QUIRK_VALID_IS_CONFIDENCE;