filter: fix constant acceleration for the X230

The x230 has a special acceleration method that relies on the touchpad magic
slowdown. This was missing from commit c8da19b50a30d8, making two-finger
scroll motions unusably fast

https://bugs.freedesktop.org/show_bug.cgi?id=91819

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/src/filter.c b/src/filter.c
index 5df50d381b7caf8d2430d0eba1d6664170a0eac5..a6468579200d99a2ee0c02ac1afb10259ae5a5e0 100644 (file)
--- a/src/filter.c
+++ b/src/filter.c
@@ -114,6 +114,8 @@ filter_get_speed(struct motion_filter *filter)
 #define X230_THRESHOLD v_ms2us(0.4)            /* in units/us */
 #define X230_ACCELERATION 2.0                  /* unitless factor */
 #define X230_INCLINE 1.1                       /* unitless factor */
+#define X230_MAGIC_SLOWDOWN 0.4                        /* unitless */
+#define X230_TP_MAGIC_LOW_RES_FACTOR 4.0       /* unitless */
 
 /*
  * Pointer acceleration filter constants
@@ -420,6 +422,21 @@ accelerator_filter_x230(struct motion_filter *filter,
        return accelerated;
 }
 
+static struct normalized_coords
+accelerator_filter_constant_x230(struct motion_filter *filter,
+                                const struct normalized_coords *unaccelerated,
+                                void *data, uint64_t time)
+{
+       struct normalized_coords normalized;
+       const double factor =
+               X230_MAGIC_SLOWDOWN/X230_TP_MAGIC_LOW_RES_FACTOR;
+
+       normalized.x = factor * unaccelerated->x;
+       normalized.y = factor * unaccelerated->y;
+
+       return normalized;
+}
+
 static struct normalized_coords
 touchpad_constant_filter(struct motion_filter *filter,
                         const struct normalized_coords *unaccelerated,
@@ -631,26 +648,22 @@ touchpad_lenovo_x230_accel_profile(struct motion_filter *filter,
                                      double speed_in,
                                      uint64_t time)
 {
-       /* Keep the magic factor from touchpad_accel_profile_linear.  */
-       const double X230_MAGIC_SLOWDOWN = 0.4; /* unitless */
-
        /* Those touchpads presents an actual lower resolution that what is
         * advertised. We see some jumps from the cursor due to the big steps
         * in X and Y when we are receiving data.
         * Apply a factor to minimize those jumps at low speed, and try
         * keeping the same feeling as regular touchpads at high speed.
         * It still feels slower but it is usable at least */
-       const double TP_MAGIC_LOW_RES_FACTOR = 4.0; /* unitless */
        double factor; /* unitless */
        struct pointer_accelerator *accel_filter =
                (struct pointer_accelerator *)filter;
 
        double f1, f2; /* unitless */
        const double max_accel = accel_filter->accel *
-                                 TP_MAGIC_LOW_RES_FACTOR; /* unitless factor */
+                                 X230_TP_MAGIC_LOW_RES_FACTOR; /* unitless factor */
        const double threshold = accel_filter->threshold /
-                                 TP_MAGIC_LOW_RES_FACTOR; /* units/us */
-       const double incline = accel_filter->incline * TP_MAGIC_LOW_RES_FACTOR;
+                                 X230_TP_MAGIC_LOW_RES_FACTOR; /* units/us */
+       const double incline = accel_filter->incline * X230_TP_MAGIC_LOW_RES_FACTOR;
 
        /* Note: the magic values in this function are obtained by
         * trial-and-error. No other meaning should be interpreted.
@@ -658,14 +671,14 @@ touchpad_lenovo_x230_accel_profile(struct motion_filter *filter,
         * pointer_accel_profile_linear(), look at the git history of that
         * function for an explaination of what the min/max/etc. does.
         */
-       speed_in *= X230_MAGIC_SLOWDOWN / TP_MAGIC_LOW_RES_FACTOR;
+       speed_in *= X230_MAGIC_SLOWDOWN / X230_TP_MAGIC_LOW_RES_FACTOR;
 
        f1 = min(1, v_us2ms(speed_in) * 5);
        f2 = 1 + (v_us2ms(speed_in) - v_us2ms(threshold)) * incline;
 
        factor = min(max_accel, f2 > 1 ? f2 : f1);
 
-       return factor * X230_MAGIC_SLOWDOWN / TP_MAGIC_LOW_RES_FACTOR;
+       return factor * X230_MAGIC_SLOWDOWN / X230_TP_MAGIC_LOW_RES_FACTOR;
 }
 
 double
@@ -795,7 +808,7 @@ create_pointer_accelerator_filter_touchpad(int dpi)
 
 struct motion_filter_interface accelerator_interface_x230 = {
        .filter = accelerator_filter_x230,
-       .filter_constant = accelerator_filter_noop,
+       .filter_constant = accelerator_filter_constant_x230,
        .restart = accelerator_restart,
        .destroy = accelerator_destroy,
        .set_speed = accelerator_set_speed,