feat(gamepad): Windows Steam Deck backend — Steam-Input-promoted UMDF virtual Deck

The N4 GO verdict, productized. GamepadPref::SteamDeck on a Windows host
now builds a real virtual Deck instead of folding to DualSense: games
get native Deck glyphs + both trackpads + gyro + all four back grips
through Steam Input's own remapping.

- steam_deck_windows.rs: DeckWinPad/DeckWinProto/SteamDeckWindowsManager
  over the sealed shm channel, sharing the whole Linux Deck codec
  (steam_proto now compiles on Windows too — it was already pure). The
  SwDevice identity carries usb_mi: Some(2): the &MI_02 hardware-id
  token hidclass mirrors into the HID child and Steam parses as the
  wired controller interface — the promotion gate.
- Driver: DEVTYPE_STEAMDECK (3) graduates from the spike — SET_FEATURE
  0xEB rumble / 0x8F haptic pulses are republished to the host through
  the output slot (report-id-0 prefixed, so parse_steam_output sees the
  Linux wire shape), and the 0xAE/GET_STRING serial + 0x83 unit id are
  per-pad (read from the section's pad_index; PFDK<unit-id> matches
  steam_proto::deck_serial).
- Router: SteamDeck arms in the Windows Pads paths; pick_gamepad flips
  SteamDeck-if-windows -> SteamDeck (the DualSense fold retires);
  dualsense-windows-test grows --deck.

ON-GLASS VALIDATED on .173 (rebuilt signed driver 9.9.0714.12xx
installed, Steam live): the manager-created pad (index 1) enumerates
with per-pad serial PFDK50460001, Steam logs Interface: 2 ->
'!! Steam controller device opened' -> 'Steam Controller reserving
XInput slot 0' -> PollState 2 (actively polling our cycling input
frames) -> mapping activated; clean teardown on exit. Rumble round-trip
through a real game remains an on-glass debt (nothing sent 0xEB during
the idle hold).

Known gap vs Linux: no physical-Steam-controller conflict degrade on
Windows yet (degrade_steam_on_conflict is Linux-only — /sys scan); a
Windows equivalent needs SetupDi enumeration and is deferred.

Verified: .21 clippy -D warnings + 304/0 tests + fmt --all; .133 clippy
-D warnings + the WDK driver-workspace check.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/pf-driver-proto/src/lib.rs

@@ -538,10 +538,11 @@ pub mod gamepad {
     /// `device_type` = DualSense Edge (`VID_054C&PID_0DF2` HID identity — the DualSense report
     /// codec plus the four native back/Fn button bits).
     pub const DEVTYPE_DUALSENSE_EDGE: u8 = 2;
-    /// `device_type` = **N4-spike** Steam Deck identity (`VID_28DE&PID_1205`). Exists only for
-    /// the `deck-windows-spike` go/no-go probe (does Steam Input on Windows promote a
-    /// software-devnode HID Deck?) — never stamped by a session.
-    pub const DEVTYPE_STEAMDECK_SPIKE: u8 = 3;
+    /// `device_type` = Steam Deck controller (`VID_28DE&PID_1205` HID identity, the captured
+    /// controller-interface descriptor + the Steam `0x83`/`0xAE` feature contract). Promoted by
+    /// Steam Input on Windows when the devnode's synthesized USB hardware ids carry `&MI_02`
+    /// (the wired controller interface — the N4-spike finding).
+    pub const DEVTYPE_STEAMDECK: u8 = 3;
 
     /// The value a gamepad driver writes into its section's `driver_proto` field once it attaches —
     /// the host's positive "driver is alive on this section" signal (health check + version audit).

crates/punktfunk-core/src/abi.rs

@@ -885,9 +885,9 @@ pub const PUNKTFUNK_GAMEPAD_DUALSHOCK4: u32 = 4;
 /// UHID classic Steam Controller (Valve `28DE:1102`, kernel `hid-steam`): one stick + dual
 /// trackpads + two grip paddles. Honored only where available (Linux hosts); else Xbox 360.
 pub const PUNKTFUNK_GAMEPAD_STEAMCONTROLLER: u32 = 5;
-/// UHID Steam Deck controller (Valve `28DE:1205`, kernel `hid-steam`): full Deck gamepad incl. the
-/// four back grips, a right trackpad, and the IMU; re-grabbed by Steam Input with native glyphs when
-/// Steam runs on the host. Honored only where available (Linux hosts); else folds to X-Box 360.
+/// Steam Deck controller (Valve `28DE:1205`): full Deck gamepad incl. the four back grips, both
+/// trackpads, and the IMU; re-grabbed by Steam Input with native glyphs when Steam runs on the
+/// host. Honored on Linux AND Windows hosts; else folds to X-Box 360.
 pub const PUNKTFUNK_GAMEPAD_STEAMDECK: u32 = 6;
 /// DualSense Edge (Sony `054C:0DF2`): the DualSense plus two back buttons + two Fn buttons, so a
 /// client's back paddles land on native slots. Folds to `DUALSENSE` until its backend lands.

crates/punktfunk-core/src/config.rs

@@ -160,9 +160,10 @@ pub enum GamepadPref {
     /// trackpads + two grip paddles. The wire right stick drives the right pad; a left-pad contact
     /// shadows the stick (hardware multiplex). Needs Linux UHID.
     SteamController,
-    /// UHID Steam Deck controller (Valve `28DE:1205`, kernel `hid-steam`) — full Deck gamepad incl.
-    /// the four back grips (L4/L5/R4/R5), a right trackpad, and the IMU; re-grabbed by Steam Input
-    /// with native glyphs when Steam runs on the host. Needs Linux UHID.
+    /// Steam Deck controller (Valve `28DE:1205`) — full Deck gamepad incl. the four back grips
+    /// (L4/L5/R4/R5), both trackpads, and the IMU; re-grabbed by Steam Input with native glyphs
+    /// when Steam runs on the host. Linux (kernel `hid-steam` via UHID/usbip/gadget) or Windows
+    /// (UMDF minidriver, Steam-Input-promoted).
     SteamDeck,
     /// DualSense Edge (Sony `054C:0DF2`, kernel `hid-playstation` ≥ 6.3 / Windows UMDF) — the
     /// DualSense plus two back buttons + two Fn buttons, so a client's back paddles (Deck grips,

crates/punktfunk-host/src/inject.rs

@@ -527,6 +527,11 @@ pub mod pad_slots;
 #[cfg(target_os = "linux")]
 #[path = "inject/linux/steam_controller.rs"]
 pub mod steam_controller;
+/// Windows: virtual Steam Deck via the same UMDF minidriver + shared-memory channel
+/// (device-type 3) — promoted by Steam Input thanks to the `&MI_02` hardware-id synthesis.
+#[cfg(target_os = "windows")]
+#[path = "inject/windows/steam_deck_windows.rs"]
+pub mod steam_deck_windows;
 /// Linux: virtual Steam Deck via the USB gadget subsystem (`raw_gadget` + `dummy_hcd`) — the only
 /// virtual-Deck transport Steam Input promotes (presents the controller on USB interface 2).
 /// SteamOS-host only (needs `dummy_hcd` + `raw_gadget`).
@@ -534,8 +539,9 @@ pub mod steam_controller;
 #[path = "inject/linux/steam_gadget.rs"]
 pub mod steam_gadget;
 /// Transport-independent Steam Controller / Steam Deck HID contract (descriptor, byte-exact Deck
-/// serializer, XInput/rich mappers, rumble parser), used by the Linux UHID backend ([`steam_controller`]).
-#[cfg(target_os = "linux")]
+/// serializer, XInput/rich mappers, rumble parser), used by the Linux UHID backend
+/// ([`steam_controller`]) and the Windows UMDF backend ([`steam_deck_windows`]).
+#[cfg(any(target_os = "linux", target_os = "windows"))]
 #[path = "inject/proto/steam_proto.rs"]
 pub mod steam_proto;
 /// Pure fallback-remap policy (Steam-only inputs onto a non-Steam backend) + the Deck motion rescale.

crates/punktfunk-host/src/inject/windows/dualsense_windows.rs

@@ -494,7 +494,7 @@ pub fn deck_spike_hold(index: u8, secs: u64) -> Result<()> {
     // SAFETY: base points at SHM_SIZE writable bytes; the OFF_* offsets are in range. Device-type
     // FIRST, magic LAST — the same publish order the session pads use.
     unsafe {
-        *base.add(OFF_DEVTYPE) = pf_driver_proto::gamepad::DEVTYPE_STEAMDECK_SPIKE;
+        *base.add(OFF_DEVTYPE) = pf_driver_proto::gamepad::DEVTYPE_STEAMDECK;
         std::ptr::write_unaligned(base.add(OFF_PAD_INDEX) as *mut u32, index as u32);
         std::ptr::write_unaligned(base.add(OFF_INPUT) as *mut [u8; 64], neutral);
         std::ptr::write_unaligned(base as *mut u32, SHM_MAGIC);

crates/punktfunk-host/src/inject/windows/steam_deck_windows.rs

@@ -0,0 +1,228 @@
+//! Virtual Steam Deck controller on Windows via the UMDF minidriver — the Windows analogue of
+//! the Linux UHID Deck ([`super::steam_controller`]'s `SteamProto`), sharing its whole codec
+//! ([`super::steam_proto`]: the byte-exact `ID_CONTROLLER_DECK_STATE` serializer, the
+//! `XInput`/rich mappers, the `0xEB` rumble parser).
+//!
+//! Transport = the sealed shared-memory channel + a `SwDeviceCreate` devnode (device-type 3),
+//! like the PS pads — with the promotion lever the N4 spike proved: the synthesized USB
+//! hardware ids carry **`&MI_02`** (the Deck's wired controller interface), which hidclass
+//! mirrors into the HID child and hidapi/Steam parse as `bInterfaceNumber`. Steam Input then
+//! claims the pad exactly like a physical wired Deck (`!! Steam controller device opened`,
+//! XInput slot reserved — observed live on `.173`), so games get native Deck glyphs +
+//! trackpads + gyro + back grips through Steam's own remapping.
+//!
+//! Feedback: Steam drives Deck rumble (`0xEB`) and trackpad haptic pulses (`0x8F`) via
+//! SET_FEATURE on the unnumbered report; the driver republishes those into the section's
+//! output slot (report-id-0 prefixed), where [`parse_steam_output`] reads the exact wire shape
+//! the Linux path sees. No gamepad-mode entry pulse here — that gate lives in the Linux
+//! kernel's evdev parser; Steam-on-Windows reads the raw reports directly.
+
+use super::dualsense_windows::{
+    create_swdevice, SwDeviceProfile, OFF_DEVTYPE, OFF_DRIVER_PROTO, OFF_INPUT, OFF_OUTPUT,
+    OFF_OUT_SEQ, OFF_PAD_INDEX, SHM_MAGIC, SHM_SIZE,
+};
+use super::gamepad_raii::PadChannel;
+use super::steam_proto::{
+    neutral_deck_report, parse_steam_output, serialize_deck_state, SteamState, STEAM_REPORT_LEN,
+};
+use crate::inject::uhid_manager::{PadFeedback, PadProto, UhidManager};
+use anyhow::Result;
+use punktfunk_core::quic::RichInput;
+use std::time::Duration;
+
+/// A single virtual Steam Deck: the `SwDeviceCreate`'d `pf_deck_<index>` devnode plus the sealed
+/// shared-memory channel. Dropping it removes the devnode and closes both sections.
+/// `pub`: the type appears as `type Pad` in the `PadProto` impl (a public trait).
+pub struct DeckWinPad {
+    /// Per-session devnode from SwDeviceCreate, when it succeeds (RAII — `SwDeviceClose` on drop).
+    _sw: Option<super::gamepad_raii::SwDevice>,
+    /// The sealed channel: unnamed DATA section (`PadShm`) + bootstrap mailbox + handle delivery.
+    channel: PadChannel,
+    /// Watches the section's `driver_proto` field and logs attach / never-attached diagnosis.
+    attach: super::gamepad_raii::DriverAttach,
+    seq: u32,
+    last_out_seq: u32,
+}
+
+impl DeckWinPad {
+    /// Create the sealed channel, stamp `device_type = Steam Deck` FIRST + the pad index + the
+    /// neutral Deck frame + the magic LAST, then spawn the `pf_deck_<index>` devnode with the
+    /// `MI_02` USB identity Steam's promotion gate requires.
+    fn open(index: u8) -> Result<DeckWinPad> {
+        let boot_name = pf_driver_proto::gamepad::pad_boot_name(index);
+        let mut channel = PadChannel::create(boot_name.clone(), SHM_SIZE)?;
+        let base = channel.data_base();
+        // SAFETY: base points at SHM_SIZE writable bytes; the OFF_* offsets are in range.
+        unsafe {
+            *base.add(OFF_DEVTYPE) = pf_driver_proto::gamepad::DEVTYPE_STEAMDECK;
+            std::ptr::write_unaligned(base.add(OFF_PAD_INDEX) as *mut u32, index as u32);
+            std::ptr::write_unaligned(
+                base.add(OFF_INPUT) as *mut [u8; STEAM_REPORT_LEN],
+                neutral_deck_report(),
+            );
+            std::ptr::write_unaligned(base as *mut u32, SHM_MAGIC);
+        }
+        let inst = format!("pf_deck_{index}");
+        let (hsw, instance_id) = match create_swdevice(&SwDeviceProfile {
+            instance: &inst,
+            container_index: index,
+            hwid: "pf_steamdeck",
+            usb_vid_pid: "VID_28DE&PID_1205",
+            // The wired Deck controller interface — WITHOUT this the HID child carries no MI_
+            // token, hidapi reports interface 0, and Steam never claims the pad (the N4
+            // spike's run-1 failure).
+            usb_mi: Some(2),
+            description: "punktfunk Virtual Steam Deck",
+        }) {
+            Ok((h, i)) => (Some(h), i),
+            Err(e) => {
+                tracing::warn!(error = %format!("{e:#}"), "SwDeviceCreate failed; Steam Deck devnode unavailable");
+                (None, None)
+            }
+        };
+        let _sw = hsw.map(super::gamepad_raii::SwDevice::new);
+        // Bounded eager delivery — the driver must read `device_type = 3` before hidclass asks
+        // it for descriptors, or the pad would enumerate with the default DualSense identity.
+        channel.deliver_eager(Duration::from_millis(1500));
+        Ok(DeckWinPad {
+            _sw,
+            channel,
+            attach: super::gamepad_raii::DriverAttach::new(
+                "pf_steamdeck",
+                "pf_dualsense.inf", // one driver package serves every identity
+                "C:\\Users\\Public\\pfds-driver.log",
+                boot_name,
+                instance_id,
+            ),
+            seq: 0,
+            last_out_seq: 0,
+        })
+    }
+
+    /// Serialize `st` into the Deck state frame and publish it to the section's input slot.
+    fn write_state(&mut self, st: &SteamState) {
+        self.seq = self.seq.wrapping_add(1);
+        let mut r = [0u8; STEAM_REPORT_LEN];
+        serialize_deck_state(&mut r, st, self.seq);
+        // SAFETY: base points at SHM_SIZE bytes; input slot is OFF_INPUT..OFF_INPUT+64.
+        unsafe {
+            std::ptr::copy_nonoverlapping(
+                r.as_ptr(),
+                self.channel.data_base().add(OFF_INPUT),
+                r.len(),
+            )
+        };
+    }
+
+    /// Poll the section's output slot; parse a newly-published Steam command (`0xEB` rumble /
+    /// `0x8F` haptic pulse — republished by the driver off SET_FEATURE) into feedback. Also
+    /// ticks the sealed-channel delivery and the driver-attach health watcher.
+    fn service(&mut self) -> Option<(u16, u16)> {
+        self.channel.pump();
+        // SAFETY: base points at SHM_SIZE bytes.
+        let proto = unsafe {
+            std::ptr::read_unaligned(self.channel.data_base().add(OFF_DRIVER_PROTO) as *const u32)
+        };
+        self.attach.observe(proto);
+        // SAFETY: base points at SHM_SIZE bytes.
+        let seq = unsafe {
+            std::ptr::read_unaligned(self.channel.data_base().add(OFF_OUT_SEQ) as *const u32)
+        };
+        if seq == self.last_out_seq {
+            return None;
+        }
+        self.last_out_seq = seq;
+        let mut out = [0u8; 64];
+        // SAFETY: output slot is OFF_OUTPUT..OFF_OUTPUT+64 within the section.
+        unsafe {
+            std::ptr::copy_nonoverlapping(
+                self.channel.data_base().add(OFF_OUTPUT),
+                out.as_mut_ptr(),
+                64,
+            )
+        };
+        parse_steam_output(&out).rumble
+    }
+}
+
+/// The Windows-Deck half of the shared stateful manager (see [`PadProto`]): the sealed-channel
+/// open under the promoted Deck identity, the same [`SteamState`] mappers as the Linux backend,
+/// and the section feedback poll. Lifecycle (slot table, unplug sweep, heartbeat, rumble dedup)
+/// lives in [`UhidManager`].
+#[derive(Default)]
+pub struct DeckWinProto;
+
+impl PadProto for DeckWinProto {
+    type Pad = DeckWinPad;
+    type State = SteamState;
+    const LABEL: &'static str = "Steam Deck/Windows";
+    const DEVICE: &'static str = "Steam Deck";
+    const CREATE_HINT: &'static str =
+        " (install/repair: punktfunk-host.exe driver install --gamepad)";
+
+    fn open(&mut self, idx: u8) -> Result<DeckWinPad> {
+        let p = DeckWinPad::open(idx)?;
+        tracing::info!(
+            index = idx,
+            "virtual Steam Deck created (Windows UMDF shm channel, MI_02 promoted identity)"
+        );
+        Ok(p)
+    }
+
+    fn neutral(&self) -> SteamState {
+        SteamState::neutral()
+    }
+
+    /// Merge buttons/sticks/triggers, preserving the rich-plane fields (trackpads + motion +
+    /// pad clicks arrive separately and must survive a button-only frame) — identical to the
+    /// Linux `SteamProto::merge_frame`.
+    fn merge_frame(
+        &self,
+        prev: &SteamState,
+        f: &crate::gamestream::gamepad::GamepadFrame,
+    ) -> SteamState {
+        use super::steam_proto::btn;
+        let mut s = SteamState::from_gamepad(
+            f.buttons,
+            f.ls_x,
+            f.ls_y,
+            f.rs_x,
+            f.rs_y,
+            f.left_trigger,
+            f.right_trigger,
+        );
+        s.rpad_x = prev.rpad_x;
+        s.rpad_y = prev.rpad_y;
+        s.lpad_x = prev.lpad_x;
+        s.lpad_y = prev.lpad_y;
+        s.gyro = prev.gyro;
+        s.accel = prev.accel;
+        s.buttons |= prev.buttons & (btn::RPAD_TOUCH | btn::LPAD_TOUCH);
+        s.lpad_click = prev.lpad_click;
+        s.rpad_click = prev.rpad_click;
+        s
+    }
+
+    fn apply_rich(&self, st: &mut SteamState, rich: RichInput) {
+        st.apply_rich(rich);
+    }
+
+    fn write_state(&self, pad: &mut DeckWinPad, st: &SteamState) {
+        pad.write_state(st);
+    }
+
+    /// Poll the section for Steam's feedback: motor rumble on the universal 0xCA plane. The
+    /// Deck has no rich host→client feedback plane (no lightbar / adaptive triggers), so
+    /// `hidout` stays empty — parity with the Linux backend.
+    fn service(&self, pad: &mut DeckWinPad, _idx: u8) -> PadFeedback {
+        PadFeedback {
+            rumble: pad.service(),
+            hidout: Vec::new(),
+        }
+    }
+}
+
+/// All virtual Steam Deck pads of a Windows session — the analogue of the Linux
+/// `SteamControllerManager`, with the same method surface (via the shared [`UhidManager`]) as
+/// the other Windows pad managers.
+pub type SteamDeckWindowsManager = UhidManager<DeckWinProto>;

crates/punktfunk-host/src/main.rs

@@ -429,9 +429,11 @@ fn real_main() -> Result<()> {
             let xbox = args.iter().any(|a| a == "--xbox");
             // `--edge` drives the DualSense Edge backend (device_type 2) and additionally holds
             // the R4/L4 paddles on the pressed beats, so a HID read shows the Edge bits in
-            // report byte 10 (0x80|0x40) next to Cross.
+            // report byte 10 (0x80|0x40) next to Cross. `--deck` drives the Steam Deck backend
+            // (device_type 3, the MI_02-promoted identity) — watch Steam claim it live.
             let edge = args.iter().any(|a| a == "--edge");
-            let extra_buttons: u32 = if edge {
+            let deck = args.iter().any(|a| a == "--deck");
+            let extra_buttons: u32 = if edge || deck {
                 punktfunk_core::input::gamepad::BTN_PADDLE1
                     | punktfunk_core::input::gamepad::BTN_PADDLE2
             } else {
@@ -535,6 +537,11 @@ fn real_main() -> Result<()> {
                     inject::dualsense_edge_windows::DualSenseEdgeWindowsManager::new(),
                     "DualSense Edge"
                 );
+            } else if deck {
+                drive!(
+                    inject::steam_deck_windows::SteamDeckWindowsManager::new(),
+                    "Steam Deck"
+                );
             } else {
                 drive!(
                     inject::dualsense_windows::DualSenseWindowsManager::new(),

crates/punktfunk-host/src/punktfunk1.rs

@@ -1754,7 +1754,8 @@ const INJECTOR_REOPEN_BACKOFF: std::time::Duration = std::time::Duration::from_s
 ///   two identities), the XUSB companion driver (classic XInput) on Windows.
 /// - DualSense / DualSense Edge / DualShock 4 — Linux UHID `hid-playstation`, or the Windows UMDF
 ///   minidriver (device-type 0/2/1).
-/// - Steam Deck — Linux UHID `hid-steam`.
+/// - Steam Deck — Linux UHID `hid-steam` (or usbip/gadget), or the Windows UMDF minidriver
+///   (device-type 3, Steam-Input-promoted).
 ///
 /// [`resolve_pad_kind`] folds any kind a platform can't build into one it can, so this never
 /// constructs a manager the build lacks.
@@ -1787,6 +1788,8 @@ struct Pads {
     dualsense_edge_win: Option<crate::inject::dualsense_edge_windows::DualSenseEdgeWindowsManager>,
     #[cfg(target_os = "windows")]
     dualshock4_win: Option<crate::inject::dualshock4_windows::DualShock4WindowsManager>,
+    #[cfg(target_os = "windows")]
+    steamdeck_win: Option<crate::inject::steam_deck_windows::SteamDeckWindowsManager>,
 }
 
 impl Pads {
@@ -1822,6 +1825,8 @@ impl Pads {
             dualsense_edge_win: None,
             #[cfg(target_os = "windows")]
             dualshock4_win: None,
+            #[cfg(target_os = "windows")]
+            steamdeck_win: None,
         }
     }
 
@@ -1924,6 +1929,11 @@ impl Pads {
                     crate::inject::dualshock4_windows::DualShock4WindowsManager::new,
                 )
                 .handle(ev),
+            #[cfg(target_os = "windows")]
+            GamepadPref::SteamDeck => self
+                .steamdeck_win
+                .get_or_insert_with(crate::inject::steam_deck_windows::SteamDeckWindowsManager::new)
+                .handle(ev),
             _ => self
                 .xbox360
                 .get_or_insert_with(crate::inject::gamepad::GamepadManager::new)
@@ -2006,6 +2016,12 @@ impl Pads {
                     m.apply_rich(rich)
                 }
             }
+            #[cfg(target_os = "windows")]
+            GamepadPref::SteamDeck => {
+                if let Some(m) = &mut self.steamdeck_win {
+                    m.apply_rich(rich)
+                }
+            }
             _ => {}
         }
     }
@@ -2057,6 +2073,9 @@ impl Pads {
             if let Some(m) = &mut self.dualshock4_win {
                 m.pump(&mut rumble, &mut hidout);
             }
+            if let Some(m) = &mut self.steamdeck_win {
+                m.pump(&mut rumble, &mut hidout);
+            }
         }
     }
 
@@ -2099,6 +2118,9 @@ impl Pads {
             if let Some(m) = &mut self.dualshock4_win {
                 m.heartbeat(gap);
             }
+            if let Some(m) = &mut self.steamdeck_win {
+                m.heartbeat(gap);
+            }
         }
     }
 }
@@ -2783,11 +2805,10 @@ fn pick_gamepad(pref: GamepadPref, env: Option<&str>, linux: bool, windows: bool
         // are the N4 spike).
         GamepadPref::SteamDeck if linux => GamepadPref::SteamDeck,
         GamepadPref::SteamController if linux => GamepadPref::SteamController,
-        // No virtual Deck on Windows (M7) — fold to DualSense, the closest rich pad: its
-        // backend keeps gyro + trackpads + pad-click alive (the Deck's dual pads split the
-        // DualSense touchpad left/right per DsState::apply_rich). Folding to Xbox360 dropped
-        // all of that silently.
-        GamepadPref::SteamDeck if windows => GamepadPref::DualSense,
+        // Windows virtual Deck: the UMDF device-type-3 identity, Steam-Input-promoted via the
+        // MI_02 hardware-id synthesis (gamepad-new-types N4) — native Deck glyphs + trackpads +
+        // gyro + back grips, replacing the old fold to DualSense.
+        GamepadPref::SteamDeck if windows => GamepadPref::SteamDeck,
         // DualSense Edge: Linux UHID hid-playstation / Windows UMDF (device-type 2) — the plain
         // DualSense plus native back/Fn buttons, so the wire paddles stop hitting the fold/drop
         // policy. Degrades to Xbox360 elsewhere like its siblings.
@@ -5373,11 +5394,11 @@ mod tests {
         assert_eq!(pick_gamepad(Auto, Some("series"), true, false), XboxOne);
         assert_eq!(pick_gamepad(XboxOne, None, false, true), Xbox360);
 
-        // Steam Deck: native on Linux; folds to DualSense on Windows (keeps gyro + trackpads
-        // via the UMDF backend — Xbox360 would drop the whole rich plane); Xbox360 elsewhere.
+        // Steam Deck: native on Linux (UHID/usbip/gadget) AND Windows (UMDF device-type 3,
+        // Steam-Input-promoted via MI_02 — gamepad-new-types N4); Xbox360 elsewhere.
         assert_eq!(pick_gamepad(SteamDeck, None, true, false), SteamDeck);
-        assert_eq!(pick_gamepad(SteamDeck, None, false, true), DualSense);
-        assert_eq!(pick_gamepad(Auto, Some("deck"), false, true), DualSense);
+        assert_eq!(pick_gamepad(SteamDeck, None, false, true), SteamDeck);
+        assert_eq!(pick_gamepad(Auto, Some("deck"), false, true), SteamDeck);
         assert_eq!(pick_gamepad(SteamDeck, None, false, false), Xbox360);
         // Classic Steam Controller: native on Linux (UHID hid-steam); Xbox360 elsewhere.
         assert_eq!(