[PATCH 09/11] HID: hid-multitouch: check if ContactCount is given for default quirk

[Benjamin Tissoires <benjamin.tissoires@gmail.com>]

By testing the new MT_CLS_DEFAULT against the collection of device
I have[1], I noticed that eGalax ones do not work because they don't
provide the field ContactCount in their report descriptor.

Removing this quirk for this kind of device allows them to work.

[1] https://github.com/bentiss/hid-devices -> all these devices can be
reinjected in the hid subsystem through uhid (kernel > 3.6) and
hid-replay here: https://github.com/bentiss/hid-replay

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
---
 drivers/hid/hid-multitouch.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 36cf346..5e0a4d7 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -263,6 +263,9 @@ static ssize_t mt_set_quirks(struct device *dev,
 
 	td->mtclass.quirks = val;
 
+	if (!td->contactcount)
+		td->mtclass.quirks &= ~MT_QUIRK_CONTACT_COUNT_ACCURATE;
+
 	return count;
 }
 
@@ -856,6 +859,9 @@ static void mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
 
 	input_mt_init_slots(input, td->maxcontacts, td->mt_flags);
 
+	if (!td->contactcount)
+		cls->quirks &= ~MT_QUIRK_CONTACT_COUNT_ACCURATE;
+
 	td->mt_flags = 0;
 }
 
-- 
1.8.0