diff --git a/src/filter-private.h b/src/filter-private.h
index f5e8b7f7..eaf84eda 100644
--- a/src/filter-private.h
+++ b/src/filter-private.h
@@ -33,6 +33,10 @@ struct motion_filter_interface {
 			   struct motion_filter *filter,
 			   const struct normalized_coords *unaccelerated,
 			   void *data, uint64_t time);
+	struct normalized_coords (*filter_constant)(
+			   struct motion_filter *filter,
+			   const struct normalized_coords *unaccelerated,
+			   void *data, uint64_t time);
 	void (*restart)(struct motion_filter *filter,
 			void *data,
 			uint64_t time);
diff --git a/src/filter.c b/src/filter.c
index f92b9fdc..674b439b 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -64,6 +64,14 @@ filter_dispatch(struct motion_filter *filter,
 	return filter->interface->filter(filter, unaccelerated, data, time);
 }
 
+struct normalized_coords
+filter_dispatch_constant(struct motion_filter *filter,
+			 const struct normalized_coords *unaccelerated,
+			 void *data, uint64_t time)
+{
+	return filter->interface->filter_constant(filter, unaccelerated, data, time);
+}
+
 void
 filter_restart(struct motion_filter *filter,
 	       void *data, uint64_t time)
@@ -319,6 +327,14 @@ accelerator_filter(struct motion_filter *filter,
 	return accelerated;
 }
 
+static struct normalized_coords
+accelerator_filter_noop(struct motion_filter *filter,
+			const struct normalized_coords *unaccelerated,
+			void *data, uint64_t time)
+{
+	return *unaccelerated;
+}
+
 static struct normalized_coords
 accelerator_filter_low_dpi(struct motion_filter *filter,
 			   const struct normalized_coords *unaccelerated,
@@ -673,6 +689,7 @@ trackpoint_accel_profile(struct motion_filter *filter,
 
 struct motion_filter_interface accelerator_interface = {
 	.filter = accelerator_filter,
+	.filter_constant = accelerator_filter_noop,
 	.restart = accelerator_restart,
 	.destroy = accelerator_destroy,
 	.set_speed = accelerator_set_speed,
@@ -719,6 +736,7 @@ create_pointer_accelerator_filter_linear(int dpi)
 
 struct motion_filter_interface accelerator_interface_low_dpi = {
 	.filter = accelerator_filter_low_dpi,
+	.filter_constant = accelerator_filter_noop,
 	.restart = accelerator_restart,
 	.destroy = accelerator_destroy,
 	.set_speed = accelerator_set_speed,
@@ -756,6 +774,7 @@ create_pointer_accelerator_filter_touchpad(int dpi)
 
 struct motion_filter_interface accelerator_interface_x230 = {
 	.filter = accelerator_filter_x230,
+	.filter_constant = accelerator_filter_noop,
 	.restart = accelerator_restart,
 	.destroy = accelerator_destroy,
 	.set_speed = accelerator_set_speed,
@@ -793,6 +812,7 @@ create_pointer_accelerator_filter_lenovo_x230(int dpi)
 
 struct motion_filter_interface accelerator_interface_trackpoint = {
 	.filter = accelerator_filter_trackpoint,
+	.filter_constant = accelerator_filter_noop,
 	.restart = accelerator_restart,
 	.destroy = accelerator_destroy,
 	.set_speed = accelerator_set_speed,
diff --git a/src/filter.h b/src/filter.h
index fd36da49..c8ade07d 100644
--- a/src/filter.h
+++ b/src/filter.h
@@ -34,11 +34,33 @@
 
 struct motion_filter;
 
+/**
+ * Accelerate the given coordinates.
+ * Takes a set of unaccelerated deltas and accelerates them based on the
+ * current and previous motion.
+ *
+ * This is a superset of filter_dispatch_constant()
+ *
+ * @see filter_dispatch_constant
+ */
 struct normalized_coords
 filter_dispatch(struct motion_filter *filter,
 		const struct normalized_coords *unaccelerated,
 		void *data, uint64_t time);
 
+/**
+ * Apply constant motion filters, but no acceleration.
+ *
+ * Takes a set of unaccelerated deltas and applies any constant filters to
+ * it but does not accelerate the delta in the conventional sense.
+ *
+ * @see filter_dispatch
+ */
+struct normalized_coords
+filter_dispatch_constant(struct motion_filter *filter,
+			 const struct normalized_coords *unaccelerated,
+			 void *data, uint64_t time);
+
 void
 filter_restart(struct motion_filter *filter,
 	       void *data, uint64_t time);