libinput provides a
libinput tool to query state and events. This tool
takes a subcommand as argument, similar to the git command. A full
explanation of the various commands available in the libinput tool is
available in the libinput(1) man page.
The most common tools used are:
libinput list-devices: to list locally available devices, see here
libinput debug-events: to monitor and debug events, see here
libinput debug-gui: to visualize events, see here
libinput record: to record an event sequence for replaying, see here
libinput measure: measure properties on a kernel device, see here
libinput quirks: show quirks assigned to a device, see here
Most of the tools must be run as root to have access to the kernel’s
/dev/input/event* device files.
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.
This tool does not show your desktop’s configuration, just the libinput built-in defaults.
$ 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 [...]
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 clickfinger is available.
This tool is intended for human-consumption and may change its output at any time.
libinput debug-events command prints events from devices and can help
to identify why a device behaves different than expected.
$ sudo libinput debug-events --enable-tapping --set-click-method=clickfinger
All configuration options (enable/disable tapping,
etc.) are available as commandline arguments. To reproduce the event
sequence as your desktop session sees it, ensure that all options are turned
on or off as required. See the libinput-debug-events(1) man page or the
--help output for information about the available options.
When submitting a bug report, always use the
--verbose flag to get
libinput debug-events --verbose <other options>
An example output from this tool may look like the snippet below.
$ sudo libinput debug-events --enable-tapping --set-click-method=clickfinger -event2 DEVICE_ADDED Power Button seat0 default group1 cap:k -event5 DEVICE_ADDED Video Bus seat0 default group2 cap:k -event0 DEVICE_ADDED Lid Switch seat0 default group3 cap:S -event1 DEVICE_ADDED Sleep Button seat0 default group4 cap:k -event4 DEVICE_ADDED HDA Intel HDMI HDMI/DP,pcm=3 seat0 default group5 cap: -event11 DEVICE_ADDED HDA Intel HDMI HDMI/DP,pcm=7 seat0 default group6 cap: -event12 DEVICE_ADDED HDA Intel HDMI HDMI/DP,pcm=8 seat0 default group7 cap: -event13 DEVICE_ADDED HDA Intel HDMI HDMI/DP,pcm=9 seat0 default group8 cap: -event14 DEVICE_ADDED HDA Intel HDMI HDMI/DP,pcm=10 seat0 default group9 cap: -event19 DEVICE_ADDED Integrated Camera: Integrated C seat0 default group10 cap:k -event15 DEVICE_ADDED HDA Intel PCH Dock Mic seat0 default group11 cap: -event16 DEVICE_ADDED HDA Intel PCH Mic seat0 default group12 cap: -event17 DEVICE_ADDED HDA Intel PCH Dock Headphone seat0 default group13 cap: -event18 DEVICE_ADDED HDA Intel PCH Headphone seat0 default group14 cap: -event6 DEVICE_ADDED ELAN Touchscreen seat0 default group15 cap:t size 305x172mm ntouches 10 calib -event3 DEVICE_ADDED AT Translated Set 2 keyboard seat0 default group16 cap:k -event20 DEVICE_ADDED SynPS/2 Synaptics TouchPad seat0 default group17 cap:pg size 100x76mm tap(dl off) left scroll-nat scroll-2fg-edge click-buttonareas-clickfinger dwt-on -event21 DEVICE_ADDED TPPS/2 IBM TrackPoint seat0 default group18 cap:p left scroll-nat scroll-button -event7 DEVICE_ADDED ThinkPad Extra Buttons seat0 default group19 cap:k -event20 POINTER_MOTION +3.62s 2.72/ -0.93 event20 POINTER_MOTION +3.63s 1.80/ -1.42 event20 POINTER_MOTION +3.65s 6.16/ -2.28 event20 POINTER_MOTION +3.66s 6.42/ -1.99 event20 POINTER_MOTION +3.67s 8.99/ -1.42 event20 POINTER_MOTION +3.68s 11.30/ 0.00 event20 POINTER_MOTION +3.69s 21.32/ 1.42
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.
This tool does not use your desktop’s configuration, just the libinput built-in defaults.
$ sudo libinput debug-gui --enable-tapping
As with libinput debug-events, all options must be specified on the
commandline to emulate the correct behavior.
See the libinput-debug-gui(1) man page or the
--help output for information about
the available options.
libinput record and libinput replay¶
For libinput versions 1.10 and older, use Recording devices with evemu.
libinput record command records the kernel events from a specific
device node. The recorded sequence can be replayed with the
replay command. This pair of tools is crucial to capturing bugs and
reproducing them on a developer’s machine.
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:
$ sudo libinput record > touchpad.yml 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
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 print the device information and
events to the file it is redirected to. More arguments are available, see
the libinput-record(1) man page.
When reproducing a bug that crashes libinput, run inside
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”.
The longer the recording, the harder it is to identify the event sequence triggering the bug. Please keep the event sequence as short as possible.
The recording can be replayed with the
libinput replay command:
$ sudo libinput replay touchpad.yml SynPS/2 Synaptics TouchPad: /dev/input/event19 Hit enter to start replaying
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(1) and libinput-replay(1) man pages.
libinput record’s autorestart feature¶
libinput record often collects thousands of events per minute. However,
the output of
libinput record usually needs to be visually inspected
or replayed in realtime on a developer machine. It is thus imperative that
the event log is kept as short as possible.
For bugs that are difficult to reproduce use
libinput record --autorestart=2 --output-file=recording.yml.
All events will be recorded to a file named
recording.yml.<current-date-and-time> and whenever the device does not
send events for 2 seconds, a new file is created. This helps to keep
individual recordings short.
To use the
--autorestart option correctly:
libinput record --autorestart=2 --output-file=<somefilename>.yml. You may provide a timeout other than 2 if needed.
- use the device to reproduce the bug, pausing frequently for 2s and longer to rotate the logs
- when the bug triggers, immediately stop using the device and wait several seconds for the log to rotate
- Ctrl+C the
libinput recordprocess without using the device again. Attach the last recording to the bug report.
If you have to use the recorded device to stop
libinput record (e.g. to
switch windows), remember that this will cause a new recording to be
created. Thus, attach the second-to-last recording to the bug report
because this one contains the bug trigger.
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:
$ sudo libinput record --multiple --output-file=touchpad-bug.yml /dev/input/event17 /dev/input/event3 recording to 'touchpad-bug.yml'
As seen above, a user must specify
--multiple and the
Finally, all devices to be recorded must be specified on the commandline as
Replaying events is the same as for a single recording:
$ sudo libinput replay touchpad-bug.yml
Measuring device properties with libinput measure¶
libinput measure tool is a multiplexer for various sub-tools that can
measure specific properties on the device. These tools generally measure one
thing and one thing only and their usage is highly specific to the tool.
Please see the libinput-measure(1) man page for information about what
tools are available and the man page for each respective tool.