From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathias Gottschlag Subject: [PATCHv2 2/4] psmouse: Ensure that the focaltech driver reports consistent coordinates. Date: Fri, 27 Feb 2015 00:20:06 +0100 Message-ID: <1424992808-29891-3-git-send-email-mgottschlag@gmail.com> References: <1423940502-12353-1-git-send-email-mgottschlag@gmail.com> <1424992808-29891-1-git-send-email-mgottschlag@gmail.com> Return-path: Received: from mail-wg0-f47.google.com ([74.125.82.47]:42541 "EHLO mail-wg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754326AbbBZXUX (ORCPT ); Thu, 26 Feb 2015 18:20:23 -0500 In-Reply-To: <1424992808-29891-1-git-send-email-mgottschlag@gmail.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Dmitry Torokhov Cc: Hans de Goede , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Mathias Gottschlag 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 --- 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