xpad-beitong-dkms

Temporary DKMS module for patched xpad with Beitong KP-series 2.4G gamepad fix. Will be deprecated once the patch is merged upstream (expected Linux 7.3 or later).

Problem

Beitong (北通) KP-series gamepads (KP20A, KP40A, KP50B, etc.) disconnect every ~1s when using the 2.4G wireless receiver on Linux. The firmware detects the host OS and power-cycles the USB connection if it doesn't receive specific Xbox One GIP (Game Input Protocol) initialization packets.

Symptoms: USB device 20bc:5127 cycles connect/disconnect continuously; Bluetooth and USB-wired modes work fine.

Fix

This package applies Zixing Liu's patch to xpad.c, adding FLAG_FORCE_INIT which sends GIP acknowledge and announce packets during controller probing. The firmware recognizes these packets and stays in XINPUT mode.

The patch has been submitted upstream (v3, 2026-07-17) and is pending review. Once merged into the kernel, this DKMS package is no longer needed.

Installation

From AUR

yay -S xpad-beitong-dkms
# or
paru -S xpad-beitong-dkms

From source

git clone https://github.com/675076143/xpad-beitong-dkms.git
cd xpad-beitong-dkms
makepkg -si

After installation, reboot or run:

sudo modprobe -r xpad && sudo modprobe xpad

Requirements

• dkms package
• Kernel headers for your running kernel (e.g., linux-headers, linux-zen-headers, linux-cachyos-rc-headers, etc.)

How it works

1. Copies xpad.c from the running kernel's headers
2. Applies the GIP init patch
3. Registers with DKMS for automatic rebuilds on kernel updates
4. Blacklists the in-kernel xpad module to ensure the patched one loads

Compatible Devices

The following VID:PID combinations are recognized:

VID	PID	Device
20bc	5125-5128	KP20A/KP40A
20bc	512f-5130	KP70A
20bc	5133-5134	KP50B
20bc	5145-5146	KP40A/KP40B
20bc	5149-514a	KP50C
20bc	5150-5151	KP50D
20bc	5152-5153	KP50E
20bc	5154-5155	KP40D
20bc	5158-5159	KP20D
20bc	515b-515c	KP40D (White)
20bc	515d-515e	KP40F (White)
20bc	515f-5160	KP70A
20bc	5169-516a	KP40F (Black)

Upstream Status

Item	Status
Patch author	Zixing Liu
Submitted	v3, 2026-07-17
Target	Mainline Linux (expected 7.3 or later)
This DKMS	Deprecated after upstream merge

Links

• Wiki page with full investigation log
• Upstream patch discussion (linux-input)
• Arch Wiki - Gamepad (ShanWan section)