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 <mgottsch...@gmail.com> --- 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 5d8cf98..0cfc646 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); + 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((int)finger->x, 0, (int)priv->x_max); + clamped_y = clamp((int)finger->y, 0, (int)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); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html