6f39a9e1c2
Some devices, specifically some bluetooth touchpads generate quite unreliable timestamps for their events. The problem seems to be that (some of) these touchpads sample at aprox 90 Hz, but the bluetooth stack only communicates about every 30 ms (*) and then sends mutiple HID input reports in one batch. This results in 2-4 packets / SYNs every 30 ms. With timestamps really close together. The finger coordinate deltas in these packets change by aprox. the same amount between each packet when moving a finger at constant speed. But the time deltas are e.g. 28 ms, 1 ms, 1 ms resulting in calculate_tracker_velocity returning vastly different speeds for the 1st and 2nd packet, which in turn results in very "jerky" mouse pointer movement. *) Maybe it is waiting for a transmit time slot or some such. This commit adds support for a real simple timestamp smoothing algorithm, intended *only* for use with touchpads. Since touchpads will send a contineous stream of events at their sample rate when a finger is down, this filter simply assumes that any events which are under event_delta_smooth_threshold us apart are part of a smooth continuous stream of events with each event being event_delta_smooth_value us apart. Theoritically a very still finger may send the exact same coordinates and pressure twice, but even if this happens that is not a problem because a still finger generates coordinates changes below the hyst treshold so we ignore it anyways. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> |
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libinput
libinput is a library that handles input devices for display servers and other applications that need to directly deal with input devices.
It provides device detection, device handling, input device event processing and abstraction so minimize the amount of custom input code the user of libinput need to provide the common set of functionality that users expect. Input event processing includes scaling touch coordinates, generating pointer events from touchpads, pointer acceleration, etc.
libinput originates from weston, the Wayland reference compositor.
Architecture
libinput is not used directly by applications, rather it is used by the xf86-input-libinput X.Org driver or wayland compositors. The typical software stack for a system running Wayland is:
@dotfile libinput-stack-wayland.gv
Where the Wayland compositor may be Weston, mutter, KWin, etc. Note that Wayland encourages the use of toolkits, so the Wayland client (your application) does not usually talk directly to the compositor but rather employs a toolkit (e.g. GTK) to do so.
The simplified software stack for a system running X.Org is:
@dotfile libinput-stack-xorg.gv
Again, on a modern system the application does not usually talk directly to the X server using Xlib but rather employs a toolkit to do so.
Source code
The source code of libinput can be found at: http://cgit.freedesktop.org/wayland/libinput
For a list of current and past releases visit: http://www.freedesktop.org/wiki/Software/libinput/
Build instructions: http://wayland.freedesktop.org/libinput/doc/latest/building_libinput.html
Reporting Bugs
Bugs can be filed in the libinput component of Wayland: https://bugs.freedesktop.org/enter_bug.cgi?product=Wayland&component=libinput
Where possible, please provide an evemu recording of the input device and/or the event sequence in question.
See @ref reporting_bugs for more info.
Documentation
- Developer API documentation: http://wayland.freedesktop.org/libinput/doc/latest/modules.html
- High-level documentation about libinput's features: http://wayland.freedesktop.org/libinput/doc/latest/pages.html
- Build instructions: http://wayland.freedesktop.org/libinput/doc/latest/building_libinput.html
- Documentation for previous versions of libinput: https://wayland.freedesktop.org/libinput/doc/
Examples of how to use libinput are the debugging tools in the libinput repository. Developers are encouraged to look at those tools for a real-world (yet simple) example on how to use libinput.
- A commandline debugging tool: https://cgit.freedesktop.org/wayland/libinput/tree/tools/libinput-debug-events.c
- A GTK application that draws cursor/touch/tablet positions: https://cgit.freedesktop.org/wayland/libinput/tree/tools/libinput-debug-gui.c
License
libinput is licensed under the MIT license.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: [...]
See the COPYING file for the full license information.