evdev: use a different filter for low resolution touchpad on the Lenovo X230

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.

For instance, we receive:

E: 13.471932 0003 0000 16366    # EV_ABS / ABS_X                16366
E: 13.471932 0003 0001 9591     # EV_ABS / ABS_Y                9591
E: 13.471932 0000 0000 0000     # ------------ SYN_REPORT (0) ----------
E: 13.479924 0003 0000 16316    # EV_ABS / ABS_X                16316
E: 13.479924 0003 0001 9491     # EV_ABS / ABS_Y                9491
E: 13.479924 0000 0000 0000     # ------------ SYN_REPORT (0) ----------
E: 13.487939 0003 0000 16271    # EV_ABS / ABS_X                16271
E: 13.487939 0003 0001 9403     # EV_ABS / ABS_Y                9403
E: 13.487939 0000 0000 0000     # ------------ SYN_REPORT (0) ----------

-> jumps of ~50 in X in each report, and ~100 for Y.

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

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Tested-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
index cccf033de847c5d3df5f59df51605286e9823205..d5ce88036b34c3ccae92f08bd08b2e23a3e88ee6 100644 (file)
--- a/src/evdev-mt-touchpad.c
+++ b/src/evdev-mt-touchpad.c
@@ -998,6 +998,7 @@ static int
 tp_init_accel(struct tp_dispatch *tp, double diagonal)
 {
        int res_x, res_y;
+       accel_profile_func_t profile;
 
        res_x = tp->device->abs.absinfo_x->resolution;
        res_y = tp->device->abs.absinfo_y->resolution;
@@ -1021,9 +1022,16 @@ tp_init_accel(struct tp_dispatch *tp, double diagonal)
                tp->accel.y_scale_coeff = DEFAULT_ACCEL_NUMERATOR / diagonal;
        }
 
-       if (evdev_device_init_pointer_acceleration(
-                                       tp->device,
-                                       touchpad_accel_profile_linear) == -1)
+       switch (tp->device->model) {
+       case EVDEV_MODEL_LENOVO_X230:
+               profile = touchpad_lenovo_x230_accel_profile;
+               break;
+       default:
+               profile = touchpad_accel_profile_linear;
+               break;
+       }
+
+       if (evdev_device_init_pointer_acceleration(tp->device, profile) == -1)
                return -1;
 
        return 0;

diff --git a/src/evdev.c b/src/evdev.c
index e3bba93e7ea105a247451bc3c1baf8ea9476ed0a..6a9df4996068434a30448cccf54708ea9fce1976 100644 (file)
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -1429,6 +1429,7 @@ evdev_read_model(struct evdev_device *device)
                const char *property;
                enum evdev_device_model model;
        } model_map[] = {
+               { "LIBINPUT_MODEL_LENOVO_X230", EVDEV_MODEL_LENOVO_X230 },
                { NULL, EVDEV_MODEL_DEFAULT },
        };
        const struct model_map *m = model_map;

diff --git a/src/evdev.h b/src/evdev.h
index edd40119d52c8ce4ab0b185f023ccba68f0bab87..151d10316856c813ab4edb5534141f683f5f67c5 100644 (file)
--- a/src/evdev.h
+++ b/src/evdev.h
@@ -95,6 +95,7 @@ enum evdev_middlebutton_event {
 
 enum evdev_device_model {
        EVDEV_MODEL_DEFAULT,
+       EVDEV_MODEL_LENOVO_X230,
 };
 
 struct mt_slot {

diff --git a/src/filter.c b/src/filter.c
index 962d74ded7f619d525852322b8231fb9c7c91ef8..b953bee84e24ae35210b97fbd95a6d29a99e391a 100644 (file)
--- a/src/filter.c
+++ b/src/filter.c
@@ -345,3 +345,40 @@ touchpad_accel_profile_linear(struct motion_filter *filter,
 
        return speed_out * TP_MAGIC_SLOWDOWN;
 }
+
+double
+touchpad_lenovo_x230_accel_profile(struct motion_filter *filter,
+                                     void *data,
+                                     double speed_in,
+                                     uint64_t time)
+{
+       /* Keep the magic factor from touchpad_accel_profile_linear.  */
+       const double TP_MAGIC_SLOWDOWN = 0.4;
+
+       /* 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;
+       double speed_out;
+       struct pointer_accelerator *accel_filter =
+               (struct pointer_accelerator *)filter;
+
+       double s1, s2;
+       const double max_accel = accel_filter->accel *
+                                 TP_MAGIC_LOW_RES_FACTOR; /* unitless factor */
+       const double threshold = accel_filter->threshold /
+                                 TP_MAGIC_LOW_RES_FACTOR; /* units/ms */
+       const double incline = accel_filter->incline * TP_MAGIC_LOW_RES_FACTOR;
+
+       speed_in *= TP_MAGIC_SLOWDOWN / TP_MAGIC_LOW_RES_FACTOR;
+
+       s1 = min(1, speed_in * 5);
+       s2 = 1 + (speed_in - threshold) * incline;
+
+       speed_out = min(max_accel, s2 > 1 ? s2 : s1);
+
+       return speed_out * TP_MAGIC_SLOWDOWN / TP_MAGIC_LOW_RES_FACTOR;
+}

diff --git a/src/filter.h b/src/filter.h
index 70363a622f85a0613169fe1e0017bf2dacc11680..a053860169169324fad77a55469e9c89f96a68c9 100644 (file)
--- a/src/filter.h
+++ b/src/filter.h
@@ -67,4 +67,9 @@ touchpad_accel_profile_linear(struct motion_filter *filter,
                              void *data,
                              double speed_in,
                              uint64_t time);
+double
+touchpad_lenovo_x230_accel_profile(struct motion_filter *filter,
+                                     void *data,
+                                     double speed_in,
+                                     uint64_t time);
 #endif /* FILTER_H */

diff --git a/udev/90-libinput-model-quirks.hwdb b/udev/90-libinput-model-quirks.hwdb
index 02bb8f974b7bb7836ca33ef7e4971184f3445285..959be0ffc1ca8769ac12c185bab80e4ecf77d9f9 100644 (file)
--- a/udev/90-libinput-model-quirks.hwdb
+++ b/udev/90-libinput-model-quirks.hwdb
@@ -14,3 +14,11 @@
 
 #
 # Sort by brand, model
+
+##########################################
+# LENOVO
+##########################################
+
+# X230 (Tablet)
+libinput:name:SynPS/2 Synaptics TouchPad:dmi:*svnLENOVO:*:pvrThinkPadX230*
+ LIBINPUT_MODEL_LENOVO_X230=1