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@xxxxxxxxx> Tested-by: Michal Hocko <mhocko@xxxxxxxx> Signed-off-by: Ben Gamari <ben@xxxxxxxxxxxxxxxx> --- drivers/input/mouse/alps.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c index b8454af..7874f4f 100644 --- a/drivers/input/mouse/alps.c +++ b/drivers/input/mouse/alps.c @@ -1197,7 +1197,12 @@ 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; -- 2.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
