logitech-g400-config

A command-line program for setting the sampling rate and DPI settings of the Logitech G400 gaming mouse.

The program uses the hidapi library (http://www.signal11.us/oss/hidapi/) for reading/writing the HID "feature reports" of the G400 mouse.

The tool is written in Python (either 2.7 or 3.x) and uses ctypes to access the native hidapi library.

NOTE: This program works with the G400 mouse, not the G400s mouse. See https://github.com/rprichard/logitech-g400-config/issues/3 for some details, or https://tnsp.org/~ccr/files/g400s_hack.c for something that works with the G400s.

Prerequisites

Ubuntu

sudo apt-get install libhidapi-libusb0

See the security HOWTO for instructions on making the USB devices accessible to this script without needing root.

macOS

Build libhidapi.dylib with this command:

clang -Inative/hidapi native/mac/hid.c -o libhidapi.dylib \
    -arch i386 -arch x86_64 \
    -Os -shared \
    -framework CoreFoundation -framework IOKit

Unlike Linux, macOS apparently requires no security configuration.

Usage

usage: logitech-g400-config.py [show]
  Prints the current mouse settings

usage: logitech-g400-config.py set [options]
  -rRATE
    RATE is in Hz and is one of: 125, 250, 500, or 1000.  The Windows driver
    defaults to 500 Hz.
  -dDPI
    DPI is one of: 400, 800, 1800, 3600, or 3600_frozen.  With 3600_frozen, the
    DPI+/DPI- buttons no longer change the DPI and instead are treated as
    any other ordinary mouse button.

usage: logitech-g400-config.py trace
    Read mouse press/release interrupts from the Logitech-proprietary G400 USB
    interface.  This interface will report DPI+/DPI- presses/releases even with
    ordinary DPI settings.  End the tracing with Ctrl-C.

Linux Security HOWTO

Add a file, /etc/udev/rules.d/10-logitech-g400-config.rules, with contents:

SUBSYSTEM=="usb", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c245", MODE:="660", GROUP="plugdev"

Run sudo udevadm control --reload-rules.

Add your user account to the plugdev group (this has no effect if you're already in the group):

$ sudo usermod -a -G plugdev $USER
$ groups
rprichard adm cdrom sudo dip plugdev lpadmin sambashare vboxusers wireshark

Log out and back in to make sure group membership takes effect.

Unplug the mouse and plug it back in. The udev rule only applies when the operating system initializes a device.