[4.2.y-ckt stable] Patch "Input: elantech - mark protocols v2 and v3 as semi-mt" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    Input: elantech - mark protocols v2 and v3 as semi-mt

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt3.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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

>From ac856d4455cfa64458c642620f3eec28db669139 Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <benjamin.tissoires at redhat.com>
Date: Mon, 11 Jan 2016 17:35:38 -0800
Subject: Input: elantech - mark protocols v2 and v3 as semi-mt

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 at redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov at gmail.com>
Signed-off-by: Kamal Mostafa <kamal 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 537ebb0..78f93cf 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -1222,7 +1222,7 @@ 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;
--
1.9.1