[PATCH 3.16.y-ckt 089/180] Input: elantech - mark protocols v2 and v3 as semi-mt

[Luis Henriques]

3.16.7-ckt24 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>

commit 6544a1df11c48c8413071aac3316792e4678fbfb upstream.

When using a protocol v2 or v3 hardware, elantech uses the function
elantech_report_semi_mt_data() to report data. This devices are rather
creepy because if num_finger is 3, (x2,y2) is (0,0). Yes, only one valid
touch is reported.

Anyway, userspace (libinput) is now confused by these (0,0) touches,
and detect them as palm, and rejects them.

Commit 3c0213d17a09 ("Input: elantech - fix semi-mt protocol for v3 HW")
was sufficient enough for xf86-input-synaptics and libinput before it has
palm rejection. Now we need to actually tell libinput that this device is
a semi-mt one and it should not rely on the actual values of the 2 touches.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 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 f6f44bc78a75..447b4545c7f7 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -1113,7 +1113,7 @@ static int elantech_set_input_params(struct psmouse *psmouse)
 			input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
 					     ETP_WMAX_V2, 0, 0);
 		}
-		input_mt_init_slots(dev, 2, 0);
+		input_mt_init_slots(dev, 2, INPUT_MT_SEMI_MT);
 		input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
 		input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
 		break;