4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Hutterer <peter.hutterer@xxxxxxxxx> [ Upstream commit 19eb4ed1141bd1096b9bc84ba9c4d03d5830c143 ] input_mt_init_slots() resets the ABS_X/Y fuzz to 0 and expects the driver to call input_mt_report_pointer_emulation(). That is based on the MT position bits which are already defuzzed - hence a fuzz of 0. In the case of synaptics semi-mt devices, we report the ABS_X/Y axes manually. This results in the MT position being defuzzed but the single-touch emulation missing that defuzzing. Work around this by re-initializing the ABS_X/Y axes after the MT axis to get the same fuzz value back. https://bugs.freedesktop.org/show_bug.cgi?id=104533 Signed-off-by: Peter Hutterer <peter.hutterer@xxxxxxxxx> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/input/mouse/synaptics.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/drivers/input/mouse/synaptics.c +++ b/drivers/input/mouse/synaptics.c @@ -1280,6 +1280,16 @@ static void set_input_params(struct psmo INPUT_MT_POINTER | (cr48_profile_sensor ? INPUT_MT_TRACK : INPUT_MT_SEMI_MT)); + + /* + * For semi-mt devices we send ABS_X/Y ourselves instead of + * input_mt_report_pointer_emulation. But + * input_mt_init_slots() resets the fuzz to 0, leading to a + * filtered ABS_MT_POSITION_X but an unfiltered ABS_X + * position. Let's re-initialize ABS_X/Y here. + */ + if (!cr48_profile_sensor) + set_abs_position_params(dev, &priv->info, ABS_X, ABS_Y); } if (SYN_CAP_PALMDETECT(info->capabilities))