On Mon, Feb 02, 2015 at 02:15:58PM -0500, Benjamin Tissoires wrote: > When tapping a clickpad with two fingers, there is a chance that the > sensor sees first only one finger, and at the next scan only the > second one. > In this case, the sensors says that there has been only one finger > on the clickpad, which moved really fast between two scans. > > We can try to counter this by adding a limit to what an actual finger > can move between 2 scans. > A distance of 1cm between two scans for one finger seems reasonable. > > However, this is not really accurate because the resolution in X and in Y > differs. But heh, that's how the in-kernel tracking works right now, and > its job is quite good, even with this approximation. > > This parameter solves most of the jumps observed, not all of them however. > But this is a hardware defect, and we might not be able to get something > better without much heavier computations. > > Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=76722 > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> Applied, thank you. > --- > drivers/input/mouse/synaptics.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c > index a3692e3..bee0387 100644 > --- a/drivers/input/mouse/synaptics.c > +++ b/drivers/input/mouse/synaptics.c > @@ -67,6 +67,9 @@ > #define X_MAX_POSITIVE 8176 > #define Y_MAX_POSITIVE 8176 > > +/* maximum ABS_MT_POSITION displacement (in mm) */ > +#define DMAX 10 > + > /***************************************************************************** > * Stuff we need even when we do not want native Synaptics support > ****************************************************************************/ > @@ -809,7 +812,7 @@ static void synaptics_report_mt_data(struct psmouse *psmouse, > pos[i].y = synaptics_invert_y(hw[i]->y); > } > > - input_mt_assign_slots(dev, slot, pos, nsemi, 0); > + input_mt_assign_slots(dev, slot, pos, nsemi, DMAX * priv->x_res); > > for (i = 0; i < nsemi; i++) { > input_mt_slot(dev, slot[i]); > -- > 2.1.0 > -- Dmitry -- 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
