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authorBen Gamari <ben@smart-cactus.org>2016-10-04 21:40:44 +0300
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2016-10-04 21:46:51 +0300
commita831776323e7c532ef9c88d0d62512ae15d78415 (patch)
tree08b81fcc217d0a8cacb721feda78d85c738aa810 /drivers/input/mouse
parent4777ac220c430173e297237b896932ed5fd8aaf3 (diff)
downloadlinux-a831776323e7c532ef9c88d0d62512ae15d78415.tar.xz
Input: ALPS - handle 0-pressure 1F events
While a button is held SS5 hardware will give us single-finger packets with x, y, and pressure equal to zero. This causes annoying jumps in pointer position if a touch is released while the button is held. Handle this by claiming zero contacts to ensure that no position events are provided to the user. Reviewed-by: Pali Rohár <pali.rohar@gmail.com> Tested-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Ben Gamari <ben@smart-cactus.org> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers/input/mouse')
-rw-r--r--drivers/input/mouse/alps.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
index 8e15783d2932..a76e5c6fce54 100644
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -1198,7 +1198,13 @@ static int alps_decode_ss4_v2(struct alps_fields *f,
f->mt[0].x = SS4_1F_X_V2(p);
f->mt[0].y = SS4_1F_Y_V2(p);
f->pressure = ((SS4_1F_Z_V2(p)) * 2) & 0x7f;
- f->fingers = 1;
+ /*
+ * When a button is held the device will give us events
+ * with x, y, and pressure of 0. This causes annoying jumps
+ * if a touch is released while the button is held.
+ * Handle this by claiming zero contacts.
+ */
+ f->fingers = f->pressure > 0 ? 1 : 0;
f->first_mp = 0;
f->is_mp = 0;
break;