Logitech TrueForce Linux Driver

Warning This driver is under active development and may contain bugs or incomplete features. Use at your own risk. This disclaimer will be removed once the driver reaches a stable release.

Linux kernel driver for Logitech TrueForce direct-drive racing wheels:

• Logitech RS50 (046d:c276)
• Logitech G PRO Racing Wheel for Xbox/PC (046d:c272)
• Logitech G PRO Racing Wheel for PS/PC (046d:c268)

Note: this project was previously named logitech-rs50-linux-driver. It was renamed 2026-07-02 because the driver covers the whole TrueForce direct-drive family, not just the RS50. Old GitHub links and clones redirect automatically; nothing changes for installed systems (the kernel module and DKMS package were always named hid-logitech-hidpp).

You get the full evdev force-feedback suite (constant, spring, damper, friction, inertia, periodic, ramp, rumble, gain), all buttons, encoders, paddles, hat switch, 16-bit pedal axes, and G Hub-equivalent settings (rotation range, FFB strength / damping / TRUEFORCE / filter, pedal curves, LIGHTSYNC LEDs) exposed via sysfs. TrueForce haptics work in supported sims under Proton via Logitech's own signed SDK DLLs - see the recipe below.

This is a patched fork of the in-kernel hid-logitech-hidpp module that replaces it. Other Logitech HID++ devices (mice, keyboards, G29 / G920 / G923 wheels, etc.) keep working through the same module.

What works

Force feedback (full evdev suite, all routed to wheel torque): FF_CONSTANT, FF_SPRING, FF_DAMPER, FF_FRICTION, FF_INERTIA, FF_PERIODIC (sine, square, triangle, saw-up, saw-down), FF_RAMP, FF_RUMBLE, FF_GAIN. Verified with fftest, the in-tree tests/ff_matrix_test, and across multiple sims (ACC, AC, BeamNG, AMS2, Le Mans Ultimate, iRacing, Dirt Rally, ETS2).

Inputs: all buttons including the G1 (logo) button, both encoder rotaries with click, both shifter paddles, 8-direction D-pad as a hat switch, 16-bit wheel axis (up to 2700° on RS50), 16-bit pedal axes (throttle, brake, clutch). Button table further down.

G Hub-equivalent settings via sysfs at /sys/class/hidraw/hidrawX/device/wheel_*. Native mode (RS50 in its native 046d:c276 enumeration):

• Rotation range (90 to 2700°)
• FFB strength, damping, TRUEFORCE level, FFB filter (with auto)
• Sensitivity (desktop mode) and brake-force (onboard mode)
• Per-pedal response curves and deadzones, combined-pedals mode
• LIGHTSYNC LED slots, colors, effects, direction, brightness
• Mode + profile switching (desktop / onboard 1-5)
• Centre calibration (wheel_calibrate, wheel_calibrate_here)

Compat mode (RS50 or G PRO enumerated as 046d:c272 / 046d:c268) exposes a reduced HID++ feature set, but the same wheel-config attributes (range, strength, trueforce, damping, FFB filter, calibration, plus LIGHTSYNC) all work via fallback feature paths decoded from G Hub captures. The wheel boots in onboard mode in compat; write 0 to wheel_profile to enter desktop mode and have live SETs take effect on the motor. See "Compat-mode behavior" below for caveats.

TrueForce in Proton sims: end-to-end verified against Assetto Corsa Competizione and Assetto Corsa EVO — full FFB, TrueForce haptics, and complete button / paddle / encoder binding all working through Logitech's own signed SDK DLLs running unmodified under Proton. The same setup is expected to work for Le Mans Ultimate, AMS2, Assetto Corsa (the original 2014 game), rFactor 2, and iRacing — they all use the same SDK. The recipe below covers the setup. Our driver passes the SDK's raw writes through unchanged; no shim, no DLL injection.

Only ACC and AC EVO are verified; the rest are expected to work because they share the SDK, not confirmed. This project does not ship an rFactor 2 plugin: rFactor 2's TrueForce support is a separate third-party component (for example the community TF4ALL SimHub plugin), not something provided here, and it is untested with this setup.

See docs/SYSFS_API.md for the complete sysfs reference.

Compatibility matrix

What to expect per wheel. Legend: ✅ verified on hardware · 🟢 supported, expected to work (shares the verified code path, not yet tested on that exact model) · — not applicable.

Capability	RS50 (c276 native / c272 compat)	G PRO Racing Wheel (c272 Xbox-PC / c268 PS-PC)
Steering, pedals, buttons, 8-way D-pad	✅	🟢
Force feedback (full evdev effect suite)	✅	🟢
TrueForce haptics (Proton + signed SDK)	✅	🟢
TrueForce texture routing for evdev effects (wheel_texture_route)	✅	🟢
Rotation range (90–2700°)	✅	🟢
FFB strength / damping / FFB filter (+ auto)	✅	🟢
TrueForce intensity / sensitivity / brake-force	✅	🟢
LIGHTSYNC RGB LEDs	✅	🟢
Centre calibration	✅	🟢
Mode / profile switching	✅	🟢

The RS50 is the development hardware, so its column is verified directly. A real G PRO runs the same rs50_ff_* code path as an RS50 in G PRO compatibility mode (which is verified), so it is expected to work; we just do not have one to confirm against. G920 / G923 keep working as a drop-in through the inherited upstream HID++ 0x8123 FFB path, but the RS50/G-PRO-specific wheel_* settings and TrueForce do not apply to them.

Force-feedback effect types

All effects are routed to the wheel's single direct-drive motor (software-emulated on top of its constant-force endpoint), verified with fftest, the in-tree tests/ff_matrix_test, and in-game:

Effect	Notes
FF_CONSTANT	Direct torque (the steering/centring force).
FF_SPRING	Use this for auto-centring. Synthetic damping (wheel_spring_damping) keeps stiff springs stable on the direct-drive motor.
FF_DAMPER, FF_FRICTION, FF_INERTIA	Condition effects, sampled from live wheel motion.
FF_RAMP	Linear force ramp.
FF_PERIODIC	sine / square / triangle / saw-up / saw-down. 20 Hz and faster ride the TrueForce texture channel by default (wheel_texture_route).
FF_RUMBLE	Streams on the TrueForce texture channel by default, so it vibrates the rim without shaking the steering axis.
FF_GAIN	Global force scaling.
FF_AUTOCENTER	Not advertised — upload an FF_SPRING instead.

Verified game support

• Assetto Corsa Competizione and Assetto Corsa EVO — verified end-to-end under Proton: steering, full FFB, and TrueForce all at the same time, with PROTON_ENABLE_HIDRAW=1 and Steam Input disabled.
• Other Logitech-SDK sims (Le Mans Ultimate, AMS2, Assetto Corsa, rFactor 2, iRacing) share the same SDK and are expected to work; not yet confirmed.

Caveats:

• Some sims (AC EVO observed) silently reset the wheel's rotation range to 90° on launch. The driver detects this within 20 seconds, corrects the reported wheel_range, and logs rotation range changed externally in dmesg. Recover by re-applying it once FFB is idle (e.g. in the game's menus): wheel_profile=0 then wheel_range=<degrees>. The in-game FFB gain is the master force control; wheel_strength is the wheel-side multiplier.
• AC EVO's map-load centring force has been observed ringing the wheel into its over-torque failsafe (the base shuts itself off; power-cycle to recover). The default wheel_spring_damping=25 is the mitigation; keep hands clear of the wheel during map loads until this is fully root-caused.

Button Mapping

Buttons use sequential indices matching Windows DirectInput for cross-platform compatibility.

Index	Button
0	A
1	X
2	B
3	Y
4	Right Paddle / Gear Right
5	Left Paddle / Gear Left
6	RT (Right Trigger)
7	LT (Left Trigger)
8	Camera/View
9	Menu
10	RSB (Right Stick)
11	LSB (Left Stick)
21	Right Encoder CW
22	Right Encoder CCW
23	Right Encoder Push
24	Left Encoder CW
25	Left Encoder CCW
26	Left Encoder Push
27	G1 (Logitech logo)

D-pad reports as hat switch (ABS_HAT0X / ABS_HAT0Y).

Note: Indices 12-20 are gaps in the HID descriptor (unused).

Installation

This is the path most users want: from a fresh clone to a working wheel with full force feedback and (optionally) TrueForce in SDK-aware sims under Proton.

Prerequisites

• Linux kernel 5.15 or newer (tested through 7.1)
• Kernel headers for the running kernel
• dkms, make, gcc or clang
• For TrueForce in Proton sims only: winegcc (ships with Wine on most distros), and a copy of Logitech G HUB on Windows from which to source four signed SDK DLLs. Skip these if you only want standard force feedback. You will still get full FFB (constant force, spring, damper, periodic, etc.) in every game.

There are no userspace components you need to compile by hand. The install script below handles the kernel module, the udev rule, and the SDK DLL installation into your wine prefixes.

Steps

1. Clone the repo.

   git clone https://github.com/mescon/logitech-trueforce-linux-driver.git
   cd logitech-rs50-linux-driver

2. (TrueForce only) Stage the Logitech SDK DLLs. These are Logitech's own Authenticode-signed binaries. We do not redistribute them; you must supply your own copies from a Logitech G HUB installation on Windows (or G HUB unpacked into a throwaway wine prefix on Linux). Place exactly these four files at exactly these paths inside the repo:

   sdk/Logi/Trueforce/1_3_11/trueforce_sdk_x64.dll
   sdk/Logi/Trueforce/1_3_11/trueforce_sdk_x86.dll
   sdk/Logi/wheel_sdk/9_1_0/logi_steering_wheel_x64.dll
   sdk/Logi/wheel_sdk/9_1_0/logi_steering_wheel_x86.dll
   

   See sdk/README.md for more detail. If any are missing the SDK DLL install step in (3) prints a warning and is skipped; the kernel driver itself still installs fine.

3. Run the installer.

   sudo ./tools/dkms-update.sh

   This:

   • Registers the source under /usr/src/hid-logitech-hidpp-1.0/ and runs dkms install so the kernel module rebuilds automatically on every kernel update.
   • Installs udev/70-logitech-rs50.rules, which hands wheel_* sysfs and the wheel's hidraw nodes to your session user (no sudo needed for Oversteer or echo > wheel_*).
   • If winegcc is available and the SDK DLLs are staged (step 2), copies the four DLLs into every Steam wine prefix it finds and registers the two CLSIDs in each prefix's system.reg so SDK-aware sims (ACC, Le Mans Ultimate, AMS2, AC, rF2, iRacing) load TrueForce.

4. Blacklist conflicting in-tree drivers (one-time):

   printf "blacklist hid-logitech-hidpp\nblacklist hid-logitech\n" | sudo tee /etc/modprobe.d/blacklist-hid-logitech-hidpp.conf
   sudo depmod -a

   hid-logitech-hidpp is the upstream version without RS50 / G PRO compat support, which our module replaces. hid-logitech (lg4ff) is for older wheels (G25/G27/G29) and matches the RS50, sending incorrect FFB commands that crash the wheel firmware on reconnect. Blacklisting hid-logitech does not affect G920 or G923 (those use HID++, handled by our driver), but if you also use a G25/G27/G29 you will lose lg4ff FFB on that older wheel.

5. Reload the module and replug the wheel.

   Safety: the RS50 can produce up to 8 Nm and may rotate under power. Hold the rim or keep clear whenever you load or reload the driver, replug the wheel, or switch profiles.

   sudo modprobe -r hid-logitech-hidpp 2>/dev/null
   sudo modprobe hid-logitech-hidpp

   Physically unplug then replug the wheel's USB cable (or reboot). dmesg | grep -i rs50 should show RS50: Force feedback initialized.

6. Smoke test.

   fftest /dev/input/by-id/*Logitech*event-joystick

   The wheel should respond to each effect in turn. fftest comes from the linuxconsoletools project: it's in the linuxconsole package on Arch-based distros (Arch, CachyOS, SteamOS) and linuxconsoletools on most others.

For ACC + TrueForce specifically, see "Recipe: ACC + TrueForce on RS50 or G PRO Racing Wheel" further down. Other SDK-aware sims follow the same recipe.

Updating after git pull

sudo ./tools/dkms-update.sh

Then reload as in step 5. A reboot is only needed on UEFI Secure Boot systems if the MOK key needs re-enrollment.

Adding TrueForce to a Wine prefix created later

For Steam games installed after step 3, or for non-Steam Wine prefixes (Heroic, Lutris, bottled wine):

./tools/install-tf-shim.sh --all-steam            # every Steam prefix
./tools/install-tf-shim.sh --prefix /path/to/pfx  # a single prefix

Run as your normal user, not sudo.

input group membership

Most desktop distros put interactive users in input automatically via systemd-logind uaccess. If echo > wheel_* returns EACCES:

sudo usermod -aG input "$USER"
# log out and back in

Build without DKMS (developers)

cd mainline
make
sudo rmmod hid-logitech-hidpp 2>/dev/null
sudo insmod ./hid-logitech-hidpp.ko

Recipe: SDK-aware sims (ACC, AC EVO, ...) on RS50 or G PRO

End-to-end verified against Assetto Corsa Competizione and Assetto Corsa EVO: full FFB, TrueForce haptics, and complete button / paddle / encoder binding, all delivered by Logitech's own signed SDK DLLs running unmodified under Proton. The same recipe is expected to work for the other Logitech-SDK-aware sims (Le Mans Ultimate, AMS2, Assetto Corsa, rFactor 2, iRacing). The recipe applies to both the RS50 and the G PRO Racing Wheel for Xbox/PC. Step 1 is RS50-only.

1. (RS50 only) Switch the wheel into "G PRO compatibility" mode via the OLED menu. The wheel reboots and reappears as 046d:c272, which is the PID ACC's TrueForce check accepts.
2. Set the wheel's steering angle. The compat-mode factory default is 90°, much too small to drive with. Two equivalent paths:
   • From Linux (recommended): enter desktop mode and set the range live via sysfs:

     H=$(ls -d /sys/class/hidraw/*/device/wheel_range | head -1 | xargs dirname)
     echo 0   > "$H/wheel_profile"   # desktop mode
     echo 540 > "$H/wheel_range"     # 540 degrees lock-to-lock

   • From the OLED: edit the active onboard profile's stored steering angle. Each onboard profile carries its own.
3. Stage the four Logitech-signed SDK DLLs under sdk/Logi/ in the repo. We do not redistribute these; copy them out of a Logitech G HUB install on Windows (or G HUB unpacked into a throwaway wine prefix on Linux):

   sdk/Logi/Trueforce/1_3_11/trueforce_sdk_x64.dll
   sdk/Logi/Trueforce/1_3_11/trueforce_sdk_x86.dll
   sdk/Logi/wheel_sdk/9_1_0/logi_steering_wheel_x64.dll
   sdk/Logi/wheel_sdk/9_1_0/logi_steering_wheel_x86.dll
   

4. Install the DLLs into your Wine prefixes (idempotent, run as your normal user, not sudo):

   ./tools/install-tf-shim.sh --all-steam

5. Steam launch options: PROTON_ENABLE_HIDRAW=1 %command%. Required: the TF SDK only sees the wheel through hidraw nodes that Wine exposes when this is set.
6. In the game, Settings → Controls → load the "PRO Racing Wheel for Xbox/PC" preset (or the closest match), bind axes and buttons, then set the in-game Wheel Rotation / steering lock to match the angle you set in step 2. If a gamepad is plugged in, unplug or disable it during binding so the game's auto-bind does not pick it up over the wheel.

Other Logitech-SDK-aware sims (Le Mans Ultimate, AMS2, Assetto Corsa, rFactor 2, iRacing) follow the same recipe.

Compat-mode behavior

A few things look wrong but are firmware-side defaults that match Windows G Hub on the same wheel. Listed here so you do not chase them as Linux issues:

• The wheel "wants to stay centered" when no game is sending FFB. The firmware applies its own self-centering spring whenever it is idle. There is no known host command to disable it. Once a game (or the TF SDK) starts driving FFB, that overrides it.
• Default steering angle is 90° out of the factory in compat mode, not 1080°. Set it from Linux via wheel_profile=0 then wheel_range=<degrees>, or from the OLED by editing the active onboard profile's stored steering angle. Some games (Assetto Corsa EVO has been reported) appear to reset the wheel back to 90° on launch every time even when the user has set a wider range beforehand. Inspecting the SDK's HID++ traffic shows the games themselves do not write any range-set command - they never even query the range feature - so the reset is wheel-firmware-side, triggered by something in the game's open / acquire / DInput claim path. If you hit this, set the angle via the OLED on the wheel base after launching the game (the OLED change takes effect live) and pin the in-game wheel range to the same value so the firmware has no reason to re-clamp.
• Mode and slot semantics:
  • Writing 0 to wheel_profile enters desktop mode (verified against motor behaviour: subsequent live SETs to wheel_range, wheel_strength, wheel_trueforce, wheel_damping, and wheel_ffb_filter take effect on the motor immediately).
  • Writing 1..5 to wheel_profile is intended to select onboard slot N but the byte encoding our driver currently sends is wrong in compat mode; it triggers a profile-broadcast cascade and the wheel can land on an unintended slot. Use the OLED menu to select an onboard slot until that path is fixed.
• wheel_brake_force, wheel_sensitivity, wheel_ffb_filter_auto return -EOPNOTSUPP on this firmware regardless of mode. Configure them via Windows G Hub or the wheel's OLED menu.

Usage

Test Force Feedback

# Find your device
ls /dev/input/by-id/ | grep -i logi

# Test FFB (requires linuxconsole package)
fftest /dev/input/by-id/usb-Logitech_RS50*-event-joystick

Configure Settings via sysfs

Settings are exposed at /sys/class/hidraw/hidrawX/device/ (where X varies by system).

# Find your wheel's hidraw device
WHEEL_DEV=$(ls -d /sys/class/hidraw/*/device/wheel_range 2>/dev/null | head -1 | xargs dirname)
echo "Wheel found at: $WHEEL_DEV"

# Example: Set rotation to 900 degrees
echo 900 | sudo tee $WHEEL_DEV/wheel_range

# Example: Set FFB strength to 80%
echo 80 | sudo tee $WHEEL_DEV/wheel_strength

# Example: Set LED slot to CUSTOM 1 (slot 0)
echo 0 | sudo tee $WHEEL_DEV/wheel_led_slot

# Example: Set custom rainbow colors for all 10 LEDs (hex RGB triplets)
echo "ff0000 ff7f00 ffff00 00ff00 00ffff 0000ff 7f00ff ff00ff ff0080 ffffff" | sudo tee $WHEEL_DEV/wheel_led_colors
echo 1 | sudo tee $WHEEL_DEV/wheel_led_apply

Available sysfs Attributes

Mode and Profile:

Attribute	Range	Description
wheel_mode	desktop/onboard	Operating mode (Desktop or Onboard profiles)
wheel_profile	0-5	Active profile (0=Desktop, 1-5=Onboard profiles)

Force Feedback:

Attribute	Range	Description
wheel_range	90-2700	Rotation range in degrees
wheel_strength	0-100	FFB strength percentage
wheel_damping	0-100	Damping percentage
wheel_trueforce	0-100	TRUEFORCE audio-haptic level
wheel_sensitivity	0-100	Wheel sensitivity (Desktop mode only)
wheel_brake_force	0-100	Brake pedal load cell threshold (Onboard mode only)
wheel_ffb_filter	1-15	FFB smoothing level
wheel_ffb_filter_auto	0-1	Auto FFB filter (0=off, 1=on)
wheel_calibrate	0-65535 (write-only)	Raw encoder value to adopt as the new centre (RS50 and G Pro).

LIGHTSYNC LED Control:

Attribute	Range	Description
wheel_led_slot	0-4	Active custom slot (CUSTOM 1-5)
wheel_led_slot_name	string	Slot name (max 8 chars, stored on device)
wheel_led_slot_brightness	0-100	Per-slot brightness (applied when slot activated)
wheel_led_direction	0-3	Animation direction (0=L→R, 1=R→L, 2=In→Out, 3=Out→In)
wheel_led_colors	hex	10 space-separated RGB hex values (LED1-LED10)
wheel_led_effect	1-5	LED effect (1-4 = animated modes, 5 = static/custom slot colors)
wheel_led_brightness	0-100	Global LED brightness percentage
wheel_led_apply	(write)	Apply current slot config to device

Pedal Configuration:

Attribute	Range	Description
wheel_combined_pedals	0-1	Combined pedals mode
wheel_throttle_curve	0-2	Throttle response curve (0=linear, 1=low sens, 2=high sens)
wheel_brake_curve	0-2	Brake response curve
wheel_clutch_curve	0-2	Clutch response curve
wheel_throttle_deadzone	"L U"	Throttle deadzone (lower% upper%)
wheel_brake_deadzone	"L U"	Brake deadzone
wheel_clutch_deadzone	"L U"	Clutch deadzone

See docs/SYSFS_API.md for complete API documentation with examples.

Oversteer Compatibility

The driver exposes standard wheel attributes for Oversteer compatibility:

• range - Rotation range (up to 2700°)
• gain - FFB strength
• autocenter - Autocenter strength (stub - see note below)
• combine_pedals - Combined pedals mode
• damper_level - Damping level

Note on autocenter: The autocenter attribute is a stub that stores values locally but doesn't communicate with the device. G Hub doesn't expose an autocenter setting for the RS50, and modern direct-drive wheels don't need hardware centering - games calculate their own centering forces using FF_CONSTANT effects.

Note: Oversteer requires a patch for RS50 support. This patch has been submitted upstream; until merged, you can apply it manually.

The patch (oversteer-rs50-support.patch) adds:

• RS50 device detection (USB ID 046d:c276)
• 2700° rotation range support
• Correct pedal axis mapping
• udev permissions for non-root access

Applying the Patch

Option 1: System package / pip install

# Find where Oversteer is installed
python3 -c "import oversteer; print(oversteer.__file__)"
# Usually: /usr/lib/python3.x/site-packages/oversteer/__init__.py

# Apply patch (adjust path as needed)
cd /usr/lib/python3.x/site-packages/
sudo patch -p1 < /path/to/oversteer-rs50-support.patch

Option 2: From git source

git clone https://github.com/berarma/oversteer.git
cd oversteer
git apply /path/to/oversteer-rs50-support.patch
sudo pip install .

Option 3: Flatpak

Flatpak apps are sandboxed, so you need to extract, patch, and reinstall:

# Export the installed Flatpak to a bundle
flatpak build-bundle ~/.local/share/flatpak/repo oversteer.flatpak \
  io.github.berarma.Oversteer

# Unfortunately, Flatpak bundles can't be easily patched.
# For Flatpak users, the recommended approach is to:
# 1. Uninstall the Flatpak version
flatpak uninstall io.github.berarma.Oversteer

# 2. Install from source with the patch applied (Option 2 above)

# 3. Or wait for the upstream patch to be merged and Flatpak updated

udev Rule (Required for non-root access)

Create /etc/udev/rules.d/99-oversteer-rs50.rules:

SUBSYSTEM=="usb", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c276", MODE="0666", TAG+="uaccess"

Then reload:

sudo udevadm control --reload-rules && sudo udevadm trigger

Documentation

In-repo references for users and contributors:

• docs/SYSFS_API.md - every wheel_* sysfs attribute, with examples and per-mode availability (native vs. compat).
• docs/RS50_PROTOCOL_SPECIFICATION.md - HID++ feature catalog for both native and compat modes, the dedicated-endpoint FFB protocol, and the G PRO compat-mode feature decoding.
• docs/TRUEFORCE_PROTOCOL.md - interface-2 audio-haptic stream layout (init sequence, sample framing, gain/damping commands).
• sdk/README.md - inventory of Logitech's Windows SDK artifacts we reference, plus the DLL-staging layout consumed by tools/install-tf-shim.sh.

Userspace components

userspace/libtrueforce/ is a native-Linux C reimplementation of Logitech's TrueForce SDK. You do not need it for the ACC + TF recipe above - that path runs Logitech's own signed DLLs through Wine, which talk directly to our kernel driver. libtrueforce exists for native-Linux applications that want to drive TrueForce without going through Wine (for example a telemetry-driven haptic generator or a custom test rig). It has its own README and tests under userspace/libtrueforce/. Nothing in userspace/ is built or installed by the regular install flow.

Game Compatibility

The driver works with any game that supports Linux force feedback:

Game	Status	Notes
Native Linux	✓	F1, Dirt Rally 2.0, Euro Truck Simulator 2
Proton/Steam	✓	Assetto Corsa, ACC, iRacing, etc.
Wine	✓	Most racing games via Proton

Games detect the wheel as a standard Linux joystick with FF support. No special configuration needed beyond setting up controls in-game.

Proton Tips

• Enable "Steam Input" → "Gamepad with Joystick Trackpad" for some games
• Some games may need SDL_JOYSTICK_DEVICE=/dev/input/eventX environment variable

inject_pid module parameter

The driver carries an experimental kernel-side path that injects a USB HID PID Page 0x0F output collection into interface 0's descriptor and translates the resulting DirectInput PID FFB writes into our evdev FFB pipeline. It exists for racing games that have no Logitech SDK integration and rely on standard DInput PID force feedback (older sims, indie games, fftest-style standalone tools). For all SDK-aware sims listed above it is unused, because the SDK bypasses DInput FFB entirely.

Default: inject_pid=0 (off). The two non-zero values:

sudo modprobe -r hid_logitech_hidpp
# Dry-run: inject the descriptor and intercept PID output reports,
# but do NOT actuate the wheel - logs every intercepted report.
# Use this first to confirm the game is hitting our shim.
sudo modprobe hid_logitech_hidpp inject_pid=1

# Actuate: descriptor + intercept + drive the wheel. Bench-tested
# only; not yet verified end-to-end against a real non-SDK game.
sudo modprobe hid_logitech_hidpp inject_pid=2

This path is intended for Proton's default joystick layer (without PROTON_ENABLE_HIDRAW). Setting PROTON_ENABLE_HIDRAW=1 is not required and is unrelated; it routes a different game class (the SDK-aware sims covered by the recipe above) and does not interact with inject_pid.

Technical Details

The RS50 is a multi-interface USB device:

• Interface 0: Joystick input (30-byte reports) - No HID++ support
• Interface 1: HID++ 4.2 protocol (configuration, settings, feature discovery)
• Interface 2: Force feedback output (64-byte reports on endpoint 0x03)

Architecture Difference: RS50 vs G920/G923

Aspect	G920/G923 (Belt-driven)	RS50 (Direct-drive)
FFB Protocol	HID++ Feature 0x8123	Dedicated USB endpoint
FFB Commands	Via HID++ FAP messages	Raw HID output reports (01 XX)
Interface Layout	Unified	3 separate interfaces
Max Rotation	900°	2700°

Critical Implementation Detail: The RS50 driver must initialize FFB only on Interface 1 (HID++), not Interface 0 (joystick). Interface 0 lacks HID++ support and attempting FFB initialization there causes joystick input to fail. The driver uses HIDPP_QUIRK_RS50_FFB to differentiate from the standard G920 code path.

See docs/RS50_PROTOCOL_SPECIFICATION.md for complete protocol documentation.

Troubleshooting

"Invalid code 768" messages during boot

These come from the HID descriptor declaring more buttons than physically exist. This driver filters them (see rs50_input_mapping) so they never reach userspace - which means if you do see them, the wheel is being handled by hid-generic, not this driver. That happens when the wheel enumerates before the module loads. See "Wheel has no FFB / no wheel_* (stuck on hid-generic)" below.

Wheel has no FFB / no wheel_* (stuck on hid-generic)

If the wheel works as a plain joystick but has no force feedback and no wheel_* sysfs (and you see "Invalid code 768" in dmesg), hid-generic claimed it before this module was loaded. Fix it with:

sudo ./tools/rebind-wheel.sh

This loads the module and rebinds every wheel interface from hid-generic to this driver. If it reports the bind failed, the in-kernel hid-logitech-hidpp is loaded instead of this fork - run sudo ./tools/dkms-update.sh so the DKMS build shadows it, then retry.

FFB not working

1. Verify the driver is bound to the wheel, not just loaded: ls /sys/class/hidraw/*/device/wheel_range should list a path. If it does not, see "stuck on hid-generic" above.
2. Check dmesg for errors: dmesg | grep -i rs50
3. Ensure you're testing with a game/app that supports FFB

FFB "pulls the wrong way" / wheel feels unstable under Wine/Proton

If a racing game feels like the wheel wants to amplify your steering input instead of pushing back toward centre ("tips over" when nudged, no self-centering when released), the FF_CONSTANT sign compensation is probably in the wrong state for your app.

Wine and Proton's DirectInput-to-evdev translation lands FF_CONSTANT at the driver with the sign inverted relative to what native Linux evdev apps produce (this has been empirically confirmed against Assetto Corsa Competizione; we have not pinned down the exact Wine source location). The driver compensates by default, so Wine/Proton games feel right out of the box. Native-evdev tools (fftest, ffcfstress, games using SDL's FF path directly, and anyone uploading via raw EVIOCSFF) see that compensation as an unwanted flip and will feel inverted.

Toggle via sysfs:

# Resolve the wheel's sysfs dir once (the attributes live on the HID++
# interface, not necessarily hidraw0; this finds the right one):
WHEEL_DEV=$(dirname "$(ls -d /sys/class/hidraw/*/device/wheel_range | head -1)")

# Default: invert (correct for Wine/Proton games)
echo 1 | sudo tee "$WHEEL_DEV/wheel_ffb_constant_sign"

# Pass-through (correct for fftest, SDL FF, custom evdev apps)
echo 0 | sudo tee "$WHEEL_DEV/wheel_ffb_constant_sign"

If WHEEL_DEV comes back empty, the driver is not bound to the wheel (check lsmod | grep hid_logitech_hidpp and that the wheel is in PC mode), or your build predates this attribute (it was added later in the 0.9 series) - pull latest and rebuild.

Only FF_CONSTANT is affected. SPRING, DAMPER, FRICTION, INERTIA, RAMP, PERIODIC, and RUMBLE all feel identical at either toggle value.

See docs/SYSFS_API.md for details, including the ongoing investigation into where the flip actually lives.

Settings not persisting

sysfs settings are volatile and reset on driver reload. For persistent settings, add commands to a udev rule or startup script.

Wine/Proton: HIDRAW=0 vs HIDRAW=1

Wine's HID stack has two paths it can take for the wheel, and the right one depends on the game:

• PROTON_ENABLE_HIDRAW=0 (default): Wine routes the joystick interface via SDL. Suitable for native-Linux-style FFB games where no Logitech-specific SDK is involved - input flows cleanly and evdev FFB works through our driver.
• PROTON_ENABLE_HIDRAW=1: Wine exposes all wheel hidraw nodes to the Windows side. Required for any game that uses the Logitech TrueForce SDK (ACC, LMU, AMS2, AC, iRacing) - the SDK finds the wheel via Windows HID enumeration which only sees hidraw devices Wine has explicitly exposed.

If you see no FFB and the game's "wheel detection" or TrueForce check says no Logitech wheel is present, you probably need PROTON_ENABLE_HIDRAW=1 plus the steps in the SDK-aware-sims recipe above.

If the game just doesn't see any wheel at all (no FFB, ghost inputs), Wine may be holding the device through a different backend - the legacy fallback is to hide the wheel from Wine's hidraw layer entirely:

# Steam launch options:
PROTON_ENABLE_HIDRAW=0 %command%

# Or globally hide the wheel from any Wine prefix:
echo 'SUBSYSTEM=="hidraw", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c276", MODE="0000"' | \
  sudo tee /etc/udev/rules.d/99-hide-rs50-from-wine.rules
sudo udevadm control --reload-rules

Solution 2: Use SDL instead of Wine's dinput

Some games work better with SDL's joystick handling:

# Steam launch options:
SDL_JOYSTICK_HIDAPI=0 %command%

Solution 3: Check hidraw permissions

If Oversteer or sysfs settings don't work, Wine may have grabbed the hidraw device:

# Find your wheel's hidraw device number
ls -la /sys/class/hidraw/*/device/wheel_range 2>/dev/null

# Check who has the device open (replace X with your hidraw number)
sudo lsof /dev/hidrawX

# If wine processes are listed, close them or use Solution 1

Contributing

Contributions are welcome! There are several ways to help:

Code contributions: This driver is forked from JacKeTUs/hid-logitech-hidpp with RS50-specific additions. If your changes apply to other Logitech devices, please consider contributing upstream as well.

Testing: Try the driver and report issues. Include your kernel version, distribution, and any relevant dmesg output.

USB captures: If you own a Logitech wheel variant that isn't yet fully supported and want to help with reverse-engineering, open an issue and we will share the contributor capture tooling.

License

GPL-2.0-only (same as the Linux kernel)

Acknowledgments

• RS50 USB protocol reverse-engineered using Wireshark captures from G Hub on Windows
• Based on JacKeTUs/hid-logitech-hidpp which adds G Pro wheel support and improved FFB
• Upstream Linux kernel hid-logitech-hidpp driver by Benjamin Tissoires and contributors
• Oversteer by Bernat Arlandis for the wheel configuration GUI