Pass SDL_JOYSTICK_HIDAPI_LG4FF=0 to Steam so the G29 keeps force feedback

SDL3's HIDAPI lg4ff driver advertises an effect-status query it cannot
answer; BeamNG.drive 0.39 native treats the failed query as a dead effect
and the wheel goes limp (12k "Failed to get joystick3 FFB effect status"
lines per session). Steam's environment on this box is exactly this
allowlist, so the hint has to live here, not in /etc/environment.

The narrow hint only demotes the Logitech wheel to the kernel driver;
gamepads keep HIDAPI (rumble, LEDs over Bluetooth).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SS8M5wk88nJTXxDWz61KKk

steam_backlog_enforcer/_desktop_env.py

@@ -77,6 +77,13 @@ def desktop_env_args(user: str, uid: int) -> list[str]:
         # Steam still keeps its own logs/console-linux.txt; this only stops
         # the copy into journald.
         "SRT_LOGGER_USE_JOURNAL=0",
+        # SDL3's HIDAPI lg4ff driver has no effect-status query; BeamNG 0.39
+        # native treats the failed query as a dead effect and the G29 goes
+        # limp (12k "Failed to get joystick3 FFB effect status" lines per
+        # session). Narrow hint so gamepads keep HIDAPI (rumble/LEDs); only
+        # the Logitech wheel falls back to the kernel driver. Name verified
+        # against BeamNG's SDL 3.4.12 strings, 2026-09-14.
+        "SDL_JOYSTICK_HIDAPI_LG4FF=0",
     ]
 
 

steam_backlog_enforcer/tests/test_desktop_env.py

@@ -65,6 +65,16 @@ class TestDesktopEnvArgs:
         args = desktop_env_args("bob", 1000)
         assert _env_value(args, "SRT_LOGGER_USE_JOURNAL") == "0"
 
+    def test_logitech_wheel_uses_kernel_driver_not_sdl_hidapi(self) -> None:
+        """Every SDL3 game must see SDL_JOYSTICK_HIDAPI_LG4FF=0.
+
+        SDL3's hidapi lg4ff driver cannot answer effect-status queries, which
+        BeamNG 0.39 native reads as a dead effect: zero force on the G29. The
+        narrow hint keeps HIDAPI for gamepads and only demotes the wheel.
+        """
+        args = desktop_env_args("bob", 1000)
+        assert _env_value(args, "SDL_JOYSTICK_HIDAPI_LG4FF") == "0"
+
     def test_dbus_address_defaults_to_uid_path(self) -> None:
         """DBUS falls back to the uid-derived socket when unset."""
         env_copy = os.environ.copy()