From: Mathias Gottschlag Date: Sat, 7 Mar 2015 13:27:08 -0800 Subject: [4/6] Input: psmouse - ensure that focaltech reports consistent coordinates Origin: https://git.kernel.org/linus/679d83ea9390636ded518f533af0cefbade317c7 We don't know whether x_max or y_max really hold the maximum possible coordinates, and we don't know for sure whether we correctly interpret the coordinates sent by the touchpad, so we clamp the reported values to prevent confusion in userspace code. Signed-off-by: Mathias Gottschlag Signed-off-by: Dmitry Torokhov --- drivers/input/mouse/focaltech.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/input/mouse/focaltech.c b/drivers/input/mouse/focaltech.c index e8fafe8..c66e0e0 100644 --- a/drivers/input/mouse/focaltech.c +++ b/drivers/input/mouse/focaltech.c @@ -126,9 +126,17 @@ static void focaltech_report_state(struct psmouse *psmouse) input_mt_slot(dev, i); input_mt_report_slot_state(dev, MT_TOOL_FINGER, active); if (active) { - input_report_abs(dev, ABS_MT_POSITION_X, finger->x); + unsigned int clamped_x, clamped_y; + /* + * The touchpad might report invalid data, so we clamp + * the resulting values so that we do not confuse + * userspace. + */ + clamped_x = clamp(finger->x, 0U, priv->x_max); + clamped_y = clamp(finger->y, 0U, priv->y_max); + input_report_abs(dev, ABS_MT_POSITION_X, clamped_x); input_report_abs(dev, ABS_MT_POSITION_Y, - priv->y_max - finger->y); + priv->y_max - clamped_y); } } input_mt_report_pointer_emulation(dev, true);