libinput/doc/tools.dox

/**
@page tools Helper tools

libinput provides a `libinput` tool to query state and events.
The two most common invocations are
@ref libinput-list-devices and @ref libinput-debug-events. A full
explanation of the various commands available in the libinput tool is
available in the libinput(1) man page. Generally, the
tool must be run as root to have access to the kernel's @c /dev/input/event*
device files.

@section libinput-list-devices libinput list-devices

The `libinput list-devices` command shows information about devices
recognized by libinput and can help identifying why a device behaves
different than expected. For example, if a device does not show up in the
output, it is not a supported input device.

@verbatim
$ sudo libinput list-devices
[...]
Device:           SynPS/2 Synaptics TouchPad
Kernel:           /dev/input/event4
Group:            9
Seat:             seat0, default
Size:             97.33x66.86mm
Capabilities:     pointer 
Tap-to-click:     disabled
Tap drag lock:    disabled
Left-handed:      disabled
Nat.scrolling:    disabled
Middle emulation: n/a
Calibration:      n/a
Scroll methods:   *two-finger 
Click methods:    *button-areas clickfinger 
[...]
@endverbatim

The above listing shows example output for a touchpad. The
`libinput list-devices` command lists general information about the device
(the kernel event node) but also the configuration options. If an option is
"n/a" it does not exist on this device. Otherwise, the tool will show the
default configuration for this device, for options that have more than a
binary state all available options are listed, with the default one prefixed
with an asterisk (*). In the example above, the default click method is
button-areas but clickinger is available.

Note that the default configuration may differ from the configuration
applied by the desktop environment.

@note This tool is intended to be human-readable and may change its output
at any time.

@section libinput-debug-events libinput debug-events
The `libinput debug-events` command prints events from devices and can help
to identify why a device behaves different than expected.

@verbatim
$ sudo libinput debug-events --enable-tapping --set-click-method=clickfinger
@endverbatim

See the libinput(1) man page or the @c --help output for information about
the available options.

@section libinput-debug-gui libinput debug-gui

A simple GTK-based graphical tool that shows the behavior and location of
touch events, pointer motion, scroll axes and gestures. Since this tool
gathers data directly from libinput, it is thus suitable for
pointer-acceleration testing.

@verbatim
$ sudo libinput debug-gui
@endverbatim

See the libinput(1) man page or the @c --help output for information about
the available options.

@section libinput-record libinput record and libinput replay

The `libinput record` command records the **kernel** events from a specific
device node. The recorded sequence can be replayed with the `libinput
replay` command. This pair of tools is crucial to capturing bugs and
reproducing them on a developer's machine.

@note These tools are shipped with libinput, but the recorded events
are **kernel events** and independent of the libinput context. libinput does not
need to be running, it does not matter whether a user is running X.Org or
Wayland or even what version of libinput is currently running.

The use of the tools is straightforward, just run without arguments, piping
the output into a file:
@verbatim
$ sudo libinput record > touchpad.log
Available devices:
/dev/input/event0:	Lid Switch
/dev/input/event1:	Sleep Button
/dev/input/event2:	Power Button
/dev/input/event3:	AT Translated Set 2 keyboard
/dev/input/event4:	ThinkPad Extra Buttons
/dev/input/event5:	ELAN Touchscreen
/dev/input/event6:	Video Bus
/dev/input/event7:	HDA Intel HDMI HDMI/DP,pcm=3
/dev/input/event8:	HDA Intel HDMI HDMI/DP,pcm=7
/dev/input/event9:	HDA Intel HDMI HDMI/DP,pcm=8
/dev/input/event10:	HDA Intel HDMI HDMI/DP,pcm=9
/dev/input/event11:	HDA Intel HDMI HDMI/DP,pcm=10
/dev/input/event12:	HDA Intel PCH Dock Mic
/dev/input/event13:	HDA Intel PCH Mic
/dev/input/event14:	HDA Intel PCH Dock Headphone
/dev/input/event15:	HDA Intel PCH Headphone
/dev/input/event16:	Integrated Camera: Integrated C
/dev/input/event17:	SynPS/2 Synaptics TouchPad
/dev/input/event18:	TPPS/2 IBM TrackPoint
Select the device event number: 17
/dev/input/event17 recording to stdout
@endverbatim

Without arguments, `libinput record` displays the available devices and lets
the user select one. Supply the number (17 in this case for
`/dev/input/event17`) and the tool will record to the log file. More
arguments are available, see the `libinput-record` man page.

Reproduce the bug, ctrl+c and attach the output file to a bug report.
For data protection, `libinput record` obscures key codes by default, any
alphanumeric key shows up as letter "a".

@note When reproducing a bug that crashes libinput, run inside `screen` or
`tmux`.

The recording can be replayed with the `libinput replay` command:
@verbatim
$ sudo libinput replay touchpad.log
SynPS/2 Synaptics TouchPad: /dev/input/event19
Hit enter to start replaying
@endverbatim

`libinput replay` creates a new virtual device based on the description in
the log file. Hitting enter replays the event sequence once and the tool
stops once all events have been replayed. Hitting enter again replays the
sequence again, Ctrl+C stops it and removes the virtual device.

Users are advised to always replay a recorded event sequence to ensure they
have captured the bug.

More arguments are available, see the `libinput-record` and
`libinput-replay` man pages.

@subsection libinput-record-multiple Recording multiple devices at once

In some cases, an interaction between multiple devices is the cause for a
specific bug. For example, a touchpad may not work in response to keyboard
events. To accurately reproduce this sequence, the timing between multiple
devices must be correct and we need to record the events in one go.

`libinput record` has a `--multiple` argument to record multiple devices at
once. Unlike the normal invocation, this one requires a number of arguments:

@verbatim
$ sudo libinput record --multiple --output-file=touchpad-bug.log /dev/input/event17 /dev/input/event3
recording to 'touchpad-bug.log'
@endverbatim

As seen above, a user must specify `--multiple` and the `--output-file`.
Finally, all devices to be recorded must be specified on the commandline as
well.

Replaying events is the same as for a single recording:
@verbatim
$ sudo libinput replay touchpad-bug.log
@endverbatim

*/