Linux list hid devices

Helper tools

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 as seen by libinput, see here
• libinput list-kernel-devices : to list locally available devices as seen by the kernel, 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 analyze : analyse event recordings from 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

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.

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 list-kernel-devices

The libinput list-kernel-devices command shows the devices known by the kernel. This command can help identify issues when a device is not handled by libinput.

$ libinput list-kernel-devices /dev/input/event0: Sleep Button /dev/input/event1: Power Button /dev/input/event2: Power Button /dev/input/event3: Microsoft Microsoft® 2.4GHz Transceiver v9.0 /dev/input/event4: Microsoft Microsoft® 2.4GHz Transceiver v9.0 Mouse [. ]

In some cases, knowing about the HID devices behind the kernel’s event nodes can be useful. To list HID devices, supply the —hid commandline flag:

$ libinput list-kernel-devices --hid hid: - name: 'Logitech Gaming Mouse G303' id: '046d:c080' driver: 'hid-generic' hidraw: ['/dev/hidraw6'] evdev: ['/dev/input/event13'] - name: 'Logitech Gaming Mouse G303' id: '046d:c080' driver: 'hid-generic' hidraw: ['/dev/hidraw7'] evdev: ['/dev/input/event14'] - name: 'Microsoft Microsoft® 2.4GHz Transceiver v9.0' id: '045e:07a5' driver: 'hid-generic' hidraw: ['/dev/hidraw0'] evdev: ['/dev/input/event3']

This tool is intended for human-consumption and may change its output at any time.

libinput debug-events

The 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 additional information: libinput debug-events —verbose

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

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.

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 .

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.

libinput libinput -> xserver kernel -> record; record -> stdout >»/>

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

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 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 screen or tmux .

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. 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:

• run libinput record —autorestart=2 —output-file=.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 record process 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 —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:

$ sudo libinput replay touchpad-bug.yml

Measuring device properties with libinput measure

The 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.

Analyzing device events with libinput analyze

The libinput analyze tool is a multiplexer for various sub-tools that can analyze input events previously recorded from a device.

Please see the libinput-analyze(1) man page for information about what tools are available and the man page for each respective too.

Listing quirks assigned to a device

The libinput quirks tool can show quirks applied for any given device.

$ libinput quirks list /dev/input/event0 AttrLidSwitchReliability=unreliable

If the tool’s output is empty, no quirk is applied. See Device quirks for more information.

© Copyright 2019, the libinput authors.

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