Bug: Analog joystick axes with 0–65535 range are never detected by the recorder

[FireRayo]

I found and tested a possible bug in Input Remapper 2.2.1 related to analog joystick axes using a 0–65535 range.

System

• Device: ASUS ROG Xbox Ally X
• Distribution: Debian 13 Trixie
• Kernel: 7.0.13+deb13-amd64
• Input Remapper: 2.2.1
• python-evdev: 1.9.1
• Input device: ASUSTeK Computer Inc. N-KEY Device
• Gamepad interface: /dev/input/event7

Problem

After upgrading the Linux kernel, Input Remapper could correctly record digital buttons, but it was impossible to record analog joystick movements.

Linux itself detected the joysticks correctly.

Running:

evtest /dev/input/event7

showed the following analog axes working correctly:

ABS_X
ABS_Y
ABS_RX
ABS_RY

Input Remapper also received the events correctly when running:

input-remapper-gtk -d

For example, moving the left joystick completely to the right produced:

ABS_X = 65535

However, Input Remapper continued reporting:

pressed: False
direction: 1

even when the joystick reached its maximum value.

Because pressed never became True, the Record function could not record the joystick direction.

The joystick range is approximately:

0 -------- 32768 -------- 65535
            center

Suspected cause

The relevant code in:

inputremapper/gui/forward_to_ui_handler.py

contains:

if abs(event.value - mid_point) < threshold:

For an axis ranging from 0 to 65535, event.value - mid_point represents a distance from the center, while threshold appears to represent an absolute position in the axis range.

This appears to make the comparison incorrect for positive-range axes centered around 32768.

Tested fix

I changed:

if abs(event.value - mid_point) < threshold:

to:

if abs(event.value - mid_point) < abs(threshold - mid_point):

After applying this change, Input Remapper immediately started detecting and recording the joystick axes correctly.

The following inputs now work with the Record function:

ABS_X
ABS_Y
ABS_RX
ABS_RY

Digital buttons continue to work correctly as well.

Local patch used

The installed file on Debian was:

/usr/lib/python3/dist-packages/inputremapper/gui/forward_to_ui_handler.py

The change was:

- if abs(event.value - mid_point) < threshold:
+ if abs(event.value - mid_point) < abs(threshold - mid_point):

This fix has been tested successfully on the built-in controller of the ASUS ROG Xbox Ally X.

It may be useful to add tests for analog axes using ranges such as:

0 ... 65535
-32768 ... 32768

as well as asymmetric trigger ranges.