Add quirk to control velocity averaging, disable it by default

libinput applies averaging to the velocity of most pointer devices. Averaging
the velocity makes the motion look smooth and may be of benefit to bad input
devices. For good devices, however, it comes at the unfortunate price of
decreased accuaracy.

This change turns velocity averaging off by default (sets ntrackers to 2 instead
of 16) and allows for it to be turned back on via a quirk, for bad devices which
require it.

1 files changed, 6 insertions, 5 deletions

diff --git a/src/filter.h b/src/filter.h
index 7e001d2f..177acbdb 100644
--- a/src/filter.h
+++ b/src/filter.h
@@ -108,21 +108,22 @@ struct motion_filter *
 create_pointer_accelerator_filter_flat(int dpi);
 
 struct motion_filter *
-create_pointer_accelerator_filter_linear(int dpi);
+create_pointer_accelerator_filter_linear(int dpi, bool use_velocity_averaging);
 
 struct motion_filter *
-create_pointer_accelerator_filter_linear_low_dpi(int dpi);
+create_pointer_accelerator_filter_linear_low_dpi(int dpi, bool use_velocity_averaging);
 
 struct motion_filter *
 create_pointer_accelerator_filter_touchpad(int dpi,
 	uint64_t event_delta_smooth_threshold,
-	uint64_t event_delta_smooth_value);
+	uint64_t event_delta_smooth_value,
+	bool use_velocity_averaging);
 
 struct motion_filter *
-create_pointer_accelerator_filter_lenovo_x230(int dpi);
+create_pointer_accelerator_filter_lenovo_x230(int dpi, bool use_velocity_averaging);
 
 struct motion_filter *
-create_pointer_accelerator_filter_trackpoint(double multiplier);
+create_pointer_accelerator_filter_trackpoint(double multiplier, bool use_velocity_averaging);
 
 struct motion_filter *
 create_pointer_accelerator_filter_tablet(int xres, int yres);