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Commit aebb47d4 authored by Aishwarya Pant's avatar Aishwarya Pant Committed by Jonathan Corbet
Browse files

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: default avatarAishwarya Pant <aishpant@gmail.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent a10c5d91

Documentation/ABI/testing/sysfs-devices-platform-trackpoint

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+115 −0
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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.