linux/Documentation/ABI/testing/sysfs-devices-platform-trackpoint
Aishwarya Pant aebb47d4e7 Input: trackpoint: document sysfs interface
Descriptions have been collected from git commit logs, code commits and
the TrackPoint System Version 4.0 Engineering Specification.

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-03-21 09:35:01 -06:00

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What: /sys/devices/platform/i8042/.../sensitivity
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) Trackpoint sensitivity.
What: /sys/devices/platform/i8042/.../intertia
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) Negative inertia factor. High values cause the cursor to
snap backward when the trackpoint is released.
What: /sys/devices/platform/i8042/.../reach
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) Backup range for z-axis press.
What: /sys/devices/platform/i8042/.../draghys
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) The drag hysteresis controls how hard it is to drag with
z-axis pressed.
What: /sys/devices/platform/i8042/.../mindrag
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) Minimum amount of force needed to trigger dragging.
What: /sys/devices/platform/i8042/.../speed
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) Speed of the trackpoint cursor.
What: /sys/devices/platform/i8042/.../thresh
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) Minimum value for z-axis force required to trigger a press
or release, relative to the running average.
What: /sys/devices/platform/i8042/.../upthresh
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) The offset from the running average required to generate a
select (click) on z-axis on release.
What: /sys/devices/platform/i8042/.../ztime
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) This attribute determines how sharp a press has to be in
order to be recognized.
What: /sys/devices/platform/i8042/.../jenks
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) Minimum curvature in degrees required to generate a double
click without a release.
What: /sys/devices/platform/i8042/.../skipback
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) When the skipback bit is set, backup cursor movement during
releases from drags will be suppressed. The default value for
this bit is 0.
What: /sys/devices/platform/i8042/.../ext_dev
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) Disable (0) or enable (1) external pointing device.
What: /sys/devices/platform/i8042/.../press_to_select
Date: Aug, 2005
KernelVersion: 2.6.14
Contact: linux-input@vger.kernel.org
Description:
(RW) Writing a value of 1 to this file will enable the Press to
Select functions like tapping the control stick to simulate a
left click, and writing 0 will disable it.
What: /sys/devices/platform/i8042/.../drift_time
Date: Dec, 2014
KernelVersion: 3.19
Contact: linux-input@vger.kernel.org
Description:
(RW) This parameter controls the period of time to test for a
hands off condition (i.e. when no force is applied) before a
drift (noise) calibration occurs.
IBM Trackpoints have a feature to compensate for drift by
recalibrating themselves periodically. By default, if for 0.5
seconds there is no change in position, it's used as the new
zero. This duration is too low. Often, the calibration happens
when the trackpoint is in fact being used.