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authorJason Parekh <jasonparekh@gmail.com>2006-11-17 01:05:58 -0500
committerDmitry Torokhov <dtor@insightbb.com>2006-11-17 01:05:58 -0500
commit00081d3729a450c37afb01c01528f4f305806d86 (patch)
treec572b8b4da05d3828b66c91debe7a160ee259165
parenteb5d5829b368c5e32f248a70797bee5a414a2ef0 (diff)
Input: appletouch - verious updates for MacBooks
Change a bit the finger detection method used by the appletouch driver to reduce touchpad "jumpiness": - Adjust the method for detecting multiple fingers. Previously, it recognized a new finger when a low sensor reading is followed by a high sensor reading. The new method checks for 'humps' in the sensor readings, so there doesn't necessarily have to be a low sensor between two high sensors for two fingers to be triggered. This allows detecting presence of two fingers on the touchpad even when they touch each other. - Change absolute coordinate calculation to us to get rid of "jumps". Instead of using full value from a sensor once it passes the threshold subtract theshold value from the reading. - Allow adjusting threshold value via module parameter. The patch doesn't seem to affect the Powerbooks but does greatly improve the touchpad behaviour on the MacBooks. Signed-off-by: Jason Parekh <jasonparekh@gmail.com> Signed-off-by: Stelian Pop <stelian@popies.net> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
-rw-r--r--drivers/usb/input/appletouch.c47
1 files changed, 43 insertions, 4 deletions
diff --git a/drivers/usb/input/appletouch.c b/drivers/usb/input/appletouch.c
index 4c213513484..4825db4b256 100644
--- a/drivers/usb/input/appletouch.c
+++ b/drivers/usb/input/appletouch.c
@@ -154,6 +154,13 @@ MODULE_AUTHOR("Johannes Berg, Stelian Pop, Frank Arnold, Michael Hanselmann");
MODULE_DESCRIPTION("Apple PowerBooks USB touchpad driver");
MODULE_LICENSE("GPL");
+/*
+ * Make the threshold a module parameter
+ */
+static int threshold = ATP_THRESHOLD;
+module_param(threshold, int, 0644);
+MODULE_PARM_DESC(threshold, "Discards any change in data from a sensor (trackpad has hundreds of these sensors) less than this value");
+
static int debug = 1;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Activate debugging output");
@@ -183,16 +190,48 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
int i;
/* values to calculate mean */
int pcum = 0, psum = 0;
+ int is_increasing = 0;
*fingers = 0;
for (i = 0; i < nb_sensors; i++) {
- if (xy_sensors[i] < ATP_THRESHOLD)
+ if (xy_sensors[i] < threshold) {
+ if (is_increasing)
+ is_increasing = 0;
+
continue;
- if ((i - 1 < 0) || (xy_sensors[i - 1] < ATP_THRESHOLD))
+ }
+
+ /*
+ * Makes the finger detection more versatile. For example,
+ * two fingers with no gap will be detected. Also, my
+ * tests show it less likely to have intermittent loss
+ * of multiple finger readings while moving around (scrolling).
+ *
+ * Changes the multiple finger detection to counting humps on
+ * sensors (transitions from nonincreasing to increasing)
+ * instead of counting transitions from low sensors (no
+ * finger reading) to high sensors (finger above
+ * sensor)
+ *
+ * - Jason Parekh <jasonparekh@gmail.com>
+ */
+ if (i < 1 || (!is_increasing && xy_sensors[i - 1] < xy_sensors[i])) {
(*fingers)++;
- pcum += xy_sensors[i] * i;
- psum += xy_sensors[i];
+ is_increasing = 1;
+ } else if (i > 0 && xy_sensors[i - 1] >= xy_sensors[i]) {
+ is_increasing = 0;
+ }
+
+ /*
+ * Subtracts threshold so a high sensor that just passes the threshold
+ * won't skew the calculated absolute coordinate. Fixes an issue
+ * where slowly moving the mouse would occassionaly jump a number of
+ * pixels (let me restate--slowly moving the mouse makes this issue
+ * most apparent).
+ */
+ pcum += (xy_sensors[i] - threshold) * i;
+ psum += (xy_sensors[i] - threshold);
}
if (psum > 0) {