graphics/input: Add getevent input event monitor tool by HongChao6 · Pull Request #3434 · apache/nuttx-apps

HongChao6 · 2026-03-25T02:17:55Z

Summary

Add getevent, a command-line input event monitor that captures and displays real-time events from input devices.

What

getevent captures and displays real-time input events from mouse, touchscreen, and keyboard devices. It reads from input device nodes (/dev/mouse*, /dev/input*, /dev/kbd*) using non-blocking I/O with poll(), and prints structured event data via syslog.

Supported event types:

Mouse: button state, x/y coordinates, wheel (if enabled)
Touchscreen: multi-touch points with coordinates, flags, timestamps, and optional pressure/size detail
Keyboard: key code and event type

When / Why

This tool is useful during:

Driver bring-up: verify that a newly ported input driver produces correct events
Input debugging: inspect raw event data to diagnose issues like missed touches, incorrect coordinates, or stuck keys
System integration: confirm that input devices are properly registered and accessible from userspace

Without getevent, developers must write ad-hoc test programs or read device nodes manually to verify input behavior. This tool provides a ready-made, consistent way to do so.

Usage

# Auto-detect all input devices in /dev
getevent

# Monitor a specific mouse device
getevent -m /dev/mouse0

# Monitor a specific touchscreen
getevent -t /dev/input0

# Monitor a specific keyboard
getevent -k /dev/kbd0

# Combine multiple devices
getevent -m /dev/mouse0 -t /dev/input0 -k /dev/kbd0

Press Ctrl+C to stop.

Configuration

CONFIG_GRAPHICS_INPUT_GETEVENT=y            # Enable getevent
CONFIG_GRAPHICS_INPUT_GETEVENT_DETAIL_INFO=y # Optional: show touch pressure/size

cederom

Thank you @HongChao6 very useful utility :-)

Please read https://github.com/apache/nuttx/blob/master/CONTRIBUTING.md and update git commit descriptions :-)

I am wondering if nuttx-apps/testing/input would not be a better fit for this tool? The main purpose is testing / input not really graphics right? Also exiting code in graphics/input? What do you think folks? :-)

graphics/input/getevent/README.md

Add getevent utility for monitoring input events including mouse clicks/movement, multi-touch coordinates/pressure, and keyboard key presses. Supports automatic device detection in /dev and command-line device path specification with non-blocking I/O. Signed-off-by: liuhongchao <liuhongchao@xiaomi.com>

Fix format specifier mismatch where '%d' was used for int32_t type argument. Use PRId32 macro instead to ensure portable formatting across architectures. Signed-off-by: tengshuangshuang <tengshuangshuang@xiaomi.com>

Fix volatile qualifier warning in pointer assignment. Add errno logging for better error diagnostics. Replace malloc with calloc for zero-initialized allocation. Signed-off-by: liuhongchao <liuhongchao@xiaomi.com>

HongChao6 · 2026-03-25T06:34:25Z

Thank you @HongChao6 very useful utility :-)

Please read https://github.com/apache/nuttx/blob/master/CONTRIBUTING.md and update git commit descriptions :-)

I am wondering if nuttx-apps/testing/input would not be a better fit for this tool? The main purpose is testing / input not really graphics right? Also exiting code in graphics/input? What do you think folks? :-)

Thanks for the suggestion. The getevent tool shares the same input subsystem infrastructure with monkey and generator under graphics/input/. Moving getevent alone would split the input toolset.

If the community agrees that graphics/input is not the right place, I'd prefer to create a separate PR to move the entire graphics/input/ directory to testing/input/ together, rather than splitting them up in this PR.

What do you think?

graphics/input/Kconfig

acassis

@HongChao6 please create a Documentation about this Graphics Input Getevent, I think we also need some basic Documentation about Graphics Input in general

cederom · 2026-03-25T15:58:52Z

@acassis is this input tightly coupled with graphics? if not and can be used as general input then maybe we should create a separate and dedicated nuttx-apps/input ? :-)

acassis · 2026-03-25T16:07:03Z

@acassis is this input tightly coupled with graphics? if not and can be used as general input then maybe we should create a separate and dedicated nuttx-apps/input ? :-)

AFAIK Graphics Input is mostly used to create Monkey testing events, but a generic Input device tester

cederom · 2026-03-25T20:40:56Z

Okay not to delay here we can put where existing input resides :-) Just an idea to uncover this functionality into its own space :-)

cederom

TODO :-)

PR description.
Documentation.
Kconfig description.

cederom · 2026-03-25T21:23:15Z

I have created a dedicated issue for discussion of input location #3436 :-)

HongChao6 · 2026-03-27T07:29:21Z

Addressed review feedback:

Updated Kconfig help text with detailed description
Updated PR description
Documentation submitted in rst format: apache/nuttx#18615
@cederom @acassis Please take another look when you have a chance. Thanks!

Remove the in-tree README.md in favor of rst documentation in the nuttx main repository. Update the Kconfig help text for getevent to describe what it does, when to use it, and why it is needed. Signed-off-by: liuhongchao <liuhongchao@xiaomi.com>

simbit18 · 2026-03-27T09:50:22Z

Hi @HongChao6, this error is not related to this PR

You will need to wait for this PR #3440 to be merged, after which you will need to rebase

====================================================================================
Configuration/Tool: sim/citest
2026-03-27 02:48:55
------------------------------------------------------------------------------------
  Cleaning...
  Configuring...
  Building NuttX...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed

  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed

  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0

  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0

100 1646k  100 1646k    0     0  3078k      0 --:--:-- --:--:-- --:--:-- 5899k

100  143k    0  143k    0     0   286k      0 --:--:-- --:--:-- --:--:--  286k
  Running NuttX...
++ pwd
+ olddir=/github/workspace/sources/nuttx
+ nuttdir=/github/workspace/sources/nuttx/boards/sim/sim/sim/configs/citest/../../../../../../
+ cd /github/workspace/sources/nuttx/boards/sim/sim/sim/configs/citest/../../../../../../
+ confpath=/github/workspace/sources/nuttx/boards/sim/sim/sim/configs/citest/config.yaml
+ jsonconf=/github/workspace/sources/nuttx/boards/sim/sim/sim/configs/citest/session.json
+ testpath=/github/workspace/nuttx-ntfc/external/nuttx-testing
+ ntfc test --testpath=/github/workspace/nuttx-ntfc/external/nuttx-testing --confpath=/github/workspace/sources/nuttx/boards/sim/sim/sim/configs/citest/config.yaml --jsonconf=/github/workspace/sources/nuttx/boards/sim/sim/sim/configs/citest/session.json
/github/workspace/sources/nuttx/../nuttx/boards/sim/sim/sim/configs/citest/run.sh: line 35: ntfc: command not found
+ ret=127
+ echo 127
+ artifacts=/github/workspace/buildartifacts/sim/citest//ntfc
+ mkdir -p /github/workspace/buildartifacts/sim/citest//ntfc
127
+ rm -f pytest.debug.log
+ mv result /github/workspace/buildartifacts/sim/citest//ntfc
mv: cannot stat 'result': No such file or directory
+ cd /github/workspace/sources/nuttx
+ exit 127
  [1/1] Normalize sim/citest
====================================================================================

HongChao6 · 2026-03-27T10:56:25Z

Hi @HongChao6, this error is not related to this PR

You will need to wait for this PR #3440 to be merged, after which you will need to rebase

Thanks for the heads up! I'll rebase once #3440 is merged.

github-actions bot added Size: L Area: Graphics labels Mar 25, 2026

cederom requested changes Mar 25, 2026

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cederom requested review from acassis, hartmannathan, linguini1, lupyuen, michallenc, raiden00pl, simbit18 and tmedicci March 25, 2026 02:42

HongChao6 force-pushed the getevent branch from be30913 to 2ca9c27 Compare March 25, 2026 03:46

HongChao6 and others added 3 commits March 25, 2026 14:07

graphics/input: Fix format specifier warning in getevent.

408b809

Fix format specifier mismatch where '%d' was used for int32_t type argument. Use PRId32 macro instead to ensure portable formatting across architectures. Signed-off-by: tengshuangshuang <tengshuangshuang@xiaomi.com>

graphics/input: Fix warnings and improve getevent robustness.

c90ba5e

Fix volatile qualifier warning in pointer assignment. Add errno logging for better error diagnostics. Replace malloc with calloc for zero-initialized allocation. Signed-off-by: liuhongchao <liuhongchao@xiaomi.com>

HongChao6 force-pushed the getevent branch 2 times, most recently from 4b49bd9 to 9413590 Compare March 25, 2026 06:30

HongChao6 requested a review from cederom March 25, 2026 06:34

acassis reviewed Mar 25, 2026

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xiaoxiang781216 previously approved these changes Mar 26, 2026

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HongChao6 dismissed stale reviews from simbit18 and xiaoxiang781216 via 3796c6e March 27, 2026 06:58

HongChao6 force-pushed the getevent branch from 9413590 to 3796c6e Compare March 27, 2026 06:58

HongChao6 mentioned this pull request Mar 27, 2026

Documentation: Add getevent input event monitor documentation. apache/nuttx#18615

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HongChao6 requested review from acassis, cederom, simbit18 and xiaoxiang781216 March 27, 2026 07:29

HongChao6 force-pushed the getevent branch from 3796c6e to 5bed08d Compare March 27, 2026 07:52

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