linux-kernel - [PATCH 06/12] Input: synaptics - fuzz position if touchpad reports reduced filtering

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Date:	Wed, 29 Jun 2011 13:07:16 +0800
From:	djkurtz@...omium.org
To:	dmitry.torokhov@...il.com, rydberg@...omail.se,
	chase.douglas@...onical.com, rubini@...l.unipv.it
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	derek.foreman@...labora.co.uk, daniel.stone@...labora.co.uk,
	olofj@...omium.org, Daniel Kurtz <djkurtz@...omium.org>
Subject: [PATCH 06/12] Input: synaptics - fuzz position if touchpad reports reduced filtering

From: Daniel Kurtz <djkurtz@...omium.org>

Synaptics touchpads indicate via a capability bit when they perform
reduced filtering on position data.
In such a case, use a non-zero fuzz value.
Fuzz = 8 was chosen empirically by observing the raw position data
reported by a clickpad indicating it had reduced filtering.

Signed-off-by: Daniel Kurtz <djkurtz@...omium.org>
---
 drivers/input/mouse/synaptics.c |   17 ++++++++++-------
 drivers/input/mouse/synaptics.h |    3 +++
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index 74b1222..dc54675 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -687,23 +687,27 @@ static psmouse_ret_t synaptics_process_byte(struct psmouse *psmouse)
 static void set_input_params(struct input_dev *dev, struct synaptics_data *priv)
 {
 	int i;
+	int fuzz = 0;
 
 	__set_bit(INPUT_PROP_POINTER, dev->propbit);
 
+	if (SYN_CAP_REDUCED_FILTERING(priv->ext_cap_0c))
+		fuzz = SYN_REDUCED_FILTER_FUZZ;
+
 	__set_bit(EV_ABS, dev->evbit);
-	input_set_abs_params(dev, ABS_X,
-			     XMIN_NOMINAL, priv->x_max ?: XMAX_NOMINAL, 0, 0);
-	input_set_abs_params(dev, ABS_Y,
-			     YMIN_NOMINAL, priv->y_max ?: YMAX_NOMINAL, 0, 0);
+	input_set_abs_params(dev, ABS_X, XMIN_NOMINAL,
+			     priv->x_max ?: XMAX_NOMINAL, fuzz, 0);
+	input_set_abs_params(dev, ABS_Y, YMIN_NOMINAL,
+			     priv->y_max ?: YMAX_NOMINAL, fuzz, 0);
 	input_set_abs_params(dev, ABS_PRESSURE, 0, 255, 0, 0);
 
 	if (SYN_CAP_ADV_GESTURE(priv->ext_cap_0c)) {
 		__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
 		input_mt_init_slots(dev, 2);
 		input_set_abs_params(dev, ABS_MT_POSITION_X, XMIN_NOMINAL,
-				     priv->x_max ?: XMAX_NOMINAL, 0, 0);
+				     priv->x_max ?: XMAX_NOMINAL, fuzz, 0);
 		input_set_abs_params(dev, ABS_MT_POSITION_Y, YMIN_NOMINAL,
-				     priv->y_max ?: YMAX_NOMINAL, 0, 0);
+				     priv->y_max ?: YMAX_NOMINAL, fuzz, 0);
 
 		input_abs_set_res(dev, ABS_MT_POSITION_X, priv->x_res);
 		input_abs_set_res(dev, ABS_MT_POSITION_Y, priv->y_res);
@@ -977,4 +981,3 @@ bool synaptics_supported(void)
 }
 
 #endif /* CONFIG_MOUSE_PS2_SYNAPTICS */
-
diff --git a/drivers/input/mouse/synaptics.h b/drivers/input/mouse/synaptics.h
index 34bedde..8a68e66 100644
--- a/drivers/input/mouse/synaptics.h
+++ b/drivers/input/mouse/synaptics.h
@@ -110,6 +110,9 @@
 #define SYN_NEWABS_RELAXED		2
 #define SYN_OLDABS			3
 
+/* amount to fuzz position data when touchpad reports reduced filtering */
+#define SYN_REDUCED_FILTER_FUZZ		8
+
 /*
  * A structure to describe the state of the touchpad hardware (buttons and pad)
  */
-- 
1.7.3.1

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