From: Ben Gamari Date: Tue, 4 Oct 2016 18:40:44 +0000 (-0700) Subject: Input: ALPS - handle 0-pressure 1F events X-Git-Tag: v4.9-rc1~15^2^2~10 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=a831776323e7c532ef9c88d0d62512ae15d78415;p=linux.git 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 Tested-by: Michal Hocko Signed-off-by: Ben Gamari Signed-off-by: Dmitry Torokhov --- 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;