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-rw-r--r--drivers/input/mouse/synaptics.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index c703d53..4dc7136 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -40,11 +40,27 @@
* Note that newer firmware allows querying device for maximum useable
* coordinates.
*/
+#define XMIN 0
+#define XMAX 6143
+#define YMIN 0
+#define YMAX 6143
#define XMIN_NOMINAL 1472
#define XMAX_NOMINAL 5472
#define YMIN_NOMINAL 1408
#define YMAX_NOMINAL 4448
+/* Size in bits of absolute position values reported by the hardware */
+#define ABS_POS_BITS 13
+
+/*
+ * Any position values from the hardware above the following limits are
+ * treated as "wrapped around negative" values that have been truncated to
+ * the 13-bit reporting range of the hardware. These are just reasonable
+ * guesses and can be adjusted if hardware is found that operates outside
+ * of these parameters.
+ */
+#define X_MAX_POSITIVE (((1 << ABS_POS_BITS) + XMAX) / 2)
+#define Y_MAX_POSITIVE (((1 << ABS_POS_BITS) + YMAX) / 2)
/*****************************************************************************
* Stuff we need even when we do not want native Synaptics support
@@ -555,6 +571,12 @@ static int synaptics_parse_hw_state(const unsigned char buf[],
hw->right = (buf[0] & 0x02) ? 1 : 0;
}
+ /* Convert wrap-around values to negative */
+ if (hw->x > X_MAX_POSITIVE)
+ hw->x -= 1 << ABS_POS_BITS;
+ if (hw->y > Y_MAX_POSITIVE)
+ hw->y -= 1 << ABS_POS_BITS;
+
return 0;
}