System Information:

• Steam AppID: 1249970 
• Game: Test Drive Unlimited Solar Crown (TDUSC) 
• OS: CachyOS Linux (64-bit) 
• Kernel: 6.19.3-2-cachyos 
• Desktop Environment: KDE Plasma 6.6.0 (Wayland) 
• CPU: 13th Gen Intel® Core™ i5-13600KF (20 threads) 
• GPU: AMD Radeon RX 7900 XTX 
• RAM: 64 GiB (62.6 GiB usable) 
• Motherboard: ASRock Z790 Steel Legend WiFi 

Proton Versions Tested:
• Proton CachyOS 10.0-20260207-slr
• GE-Proton 10-32
• Proton 9.0-4 (official Valve build)
Controllers Tested:
• Xbox Elite Series 2 (USB & Bluetooth)
• Xbox Series Controller
• Google Stadia Controller

Problem Description: Controller input is not recognized in-game while keyboard and mouse work perfectly. The system detects controllers correctly (visible in jstest-gtk with input events on /dev/input/js3), but Proton/Wine does not pass them through to the game. No SDL: Detected joystick: or XInputOpenDevice: entries appear in logs even with debug flags enabled. This affects all tested controllers and all Proton versions.

Reproduction Steps:
1. Connect any controller (tested with Xbox Elite Series 2 via USB, Xbox Series Controller, Stadia Controller)
2. Verify controller works in jstest-gtk and appears as /dev/input/js3
3. Launch Test Drive Unlimited Solar Crown with any Proton version
4. Navigate to controller settings or attempt gameplay
5. Controller inputs are ignored completely (no detection in game)
6. Keyboard and mouse input works immediately
Attempted Fixes:
Steam Input Configuration:
• Disabled Steam Input globally (Steam Settings → Controller)
• Disabled Steam Input per-game (Properties → Controller → "Disable Steam Input")
• Verified controllers appear in Steam Big Picture mode (they do)
Proton Launch Options (tested individually and in combination):
PROTON_USE_XINPUT=1
PROTON_NO_XINPUT=1
SDL_GAMECONTROLLER_IGNORE_DEVICES=0x045e/0x0b00,0x045e/0x0b13,0x045e/0xb22
SDL_JOYSTICK_HIDAPI=0
SDL_JOYSTICK_DEVICE=/dev/input/js3
PROTON_ENABLE_GAMING_INPUT=1
PROTON_ENABLE_HIDRAW=0x045e/0x0b00,0x045e/0x0b13,0x045e/0xb22
WINEDLLOVERRIDES=xinput1_4,builtin
PROTON_NO_BWRAP=1
PROTON_NO_PRESSURE_VESSEL=1
PROTON_LOG=1
WINEDEBUG=+controller,+joystick,+xinput

Registry Modifications:

• Added DisableHidraw=1 to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\winebus (dword:00000001)
• Attempted with clean prefixes after each major change
• Verified registry key persistence after Steam restart

System Configuration:

• Verified user is in input group (groups $USER shows input)
• Installed game-devices-udev package
• Verified /dev/input/js3 permissions: crw-rw-r--@ 13,3 root input
• Loaded xpad kernel module manually (sudo modprobe xpad)
• Disabled Steam Overlay (Properties → "Steam Overlay" unchecked)

Relevant Log Excerpts:

Proton CachyOS 10.0 - Initial XInput failure (without fixes):
00c0:fixme:xinput:pdo_pnp code 0xc, not implemented!
00c0:fixme:hid:build_joystick_report_descriptor More than 8 absolute axes found, ignoring.
00a0:err:ntoskrnl:ZwLoadDriver failed to create driver L"\Registry\Machine\System\CurrentControlSet\Services\winebth": c0000142

After applying DisableHidraw registry key and SDL_JOYSTICK_HIDAPI=0:
0094:00bc:fixme:xinput:pdo_pnp code 0xc, not implemented!
0094:00a0:err:ntoskrnl:ZwLoadDriver failed to create driver L"\Registry\Machine\System\CurrentControlSet\Services\winebth": c0000142
0090:009c:trace:loaddll:build_module Loaded L"C:\windows\system32\drivers\hidparse.sys"
0090:009c:trace:loaddll:build_module Loaded L"C:\windows\system32\drivers\winebus.sys"
(Note: The hid:build_joystick_report_descriptor error disappeared after registry modification, but controller still not detected. No SDL detection lines appear.)

GE-Proton 10-32 - Windows.Gaming.Input attempt:
0170:fixme:combase:RoGetActivationFactory (L"Windows.Gaming.Input.Gamepad", {8bbce529-d49c-39e9-9560-e47dde96b7c8}, 000000000147C298): semi-stub
6660.834:0094:00bc:fixme:xinput:pdo_pnp code 0xc, not implemented!
6660.841:0094:00a0:err:ntoskrnl:ZwLoadDriver failed to create driver L"\Registry\Machine\System\CurrentControlSet\Services\winebth": c0000142

GE-Proton with Xbox Series Controller (same result):
6809.742:0094:00bc:fixme:xinput:pdo_pnp code 0xc, not implemented!
6809.756:0094:00a0:err:ntoskrnl:ZwLoadDriver failed to create driver L"\Registry\Machine\System\CurrentControlSet\Services\winebth": c0000142
6809.751:0094:00bc:fixme:xinput:pdo_pnp code 0xc, not implemented!

Proton 9.0-4 - Same behavior:
6809.739:0094:00bc:fixme:xinput:pdo_pnp code 0xc, not implemented!

Critical Observations:

• Controller visible and responsive in jstest-gtk on /dev/input/js3
• No SDL: Detected joystick: entries in any Proton logs
• No XInputOpenDevice: entries in logs
• fixme:xinput:pdo_pnp code 0xc, not implemented! appears consistently across all Proton versions
• Game launches successfully with keyboard/mouse, suggesting SARD Anti-Cheat allows execution but may block input device access
• Issue persists across kernel 6.19.2 and 6.19.3

Conclusion: After exhaustive testing of all available workarounds (Steam Input settings, environment variables, kernel modules, udev rules, registry edits, sandbox disabling, and multiple Proton versions), the issue appears to be a fundamental incompatibility between the game's input handling/SARD Anti-Cheat and current Proton/Wine HID implementations on this system configuration. The pdo_pnp code 0xc error persists across all tested versions, suggesting incomplete XInput/Gamepad support for this specific title on CachyOS kernel 6.19.x.