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And expand it to encompass all pressure pads. Definition: "pressure pad" as used here as includes all touchpads that use physical pressure to convert to click, without physical hinges. Also called haptic touchpads in general parlance, Synaptics calls them ForcePads. Most (all?) pressure pads are currently advertised as INPUT_PROP_BUTTONPAD. The suggestion to identify them as pressure pads by defining the resolution on ABS_MT_PRESSURE has been in the docs since commit20ccc8dd38("Documentation: input: define ABS_PRESSURE/ABS_MT_PRESSURE resolution as grams") but few devices provide this information. In userspace it's thus impossible to determine whether a device is a true pressure pad (pressure equals pressure) or a normal clickpad with (pressure equals finger size). Commit7075ae4ac9("Input: add INPUT_PROP_HAPTIC_TOUCHPAD") introduces INPUT_PROP_HAPTIC_TOUCHPAD but restricted it to those touchpads that have support for userspace-controlled effects. Let's expand and rename that definition to include all pressure pad touchpads since those that do support FF effects can be identified by the presence of the FF_HAPTIC bit. This means: - clickpad: INPUT_PROP_BUTTONPAD - pressurepad: INPUT_PROP_BUTTONPAD + INPUT_PROP_PRESSUREPAD - pressurepad with configurable haptics: INPUT_PROP_BUTTONPAD + INPUT_PROP_PRESSUREPAD + FF_HAPTIC Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> Acked-by: Benjamin Tissoires <bentiss@kernel.org> Link: https://patch.msgid.link/20251106114534.GA405512@tassie Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.