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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>
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Documentation/ABI/testing/sysfs-devices-platform-trackpoint
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. |