From ac9c3f53b9bdd199431f72729d608e30dbbead5b Mon Sep 17 00:00:00 2001 From: Peter Hutterer Date: Wed, 29 Nov 2017 12:47:25 +1000 Subject: [PATCH] doc: update the pointer acceleration page for the 1.9 trackpoint accel Signed-off-by: Peter Hutterer --- doc/pointer-acceleration.dox | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/doc/pointer-acceleration.dox b/doc/pointer-acceleration.dox index 57be6cdc..c120565a 100644 --- a/doc/pointer-acceleration.dox +++ b/doc/pointer-acceleration.dox @@ -117,20 +117,23 @@ properties. Measuring pressure objectively across a variety of hardware is nontrivial. libinput's pointer acceleration is a function of the total available -pressure range on a device. +pressure range on a device. See @ref trackpoint_range for details. -libinput relies on some sytem-wide configured properties, specifically the -@ref udev_config. The two properties that influence trackpoint acceleration -````POINTINGSTICK_CONST_ACCEL```` which is a constant factor applied to the -trackpoint's motion data. For example, a factor of 3 will see all input data -multipled by 3. This multiplication is done by libinput. +libinput relies on some system-wide configured properties, specifically the +@ref udev_config. The property that influences trackpoint acceleration is +`LIBINPUT_ATTR_TRACKPOINT_RANGE` which specifies the total delta range for +the trackpoint. See @ref trackpoint_range for details. Additionally, some trackpoints provide the ability to adjust the sensitivity in hardware by modifying a sysfs file on the serio node. The udev property -````POINTINGSTICK_SENSITIVITY```` indicates the desired value, a udev +`POINTINGSTICK_SENSITIVITY` indicates the desired value, a udev builtin is expected to apply this to the device, i.e. libinput does not handle this property. Once applied, the sensitivity adjusts the deltas -coming out of the hardware. +coming out of the hardware. When the sensitivity changes, the trackpoint +range changes and thus the `LIBINPUT_ATTR_TRACKPOINT_RANGE` property +becomes invalid. + +As of version 1.9, libinput does not parse the `POINTINGSTICK_CONST_ACCEL` property anymore. @image html ptraccel-trackpoint.svg "Pointer acceleration curves for trackpoints"