fix(host): Linux virtual-pad feedback access — hidraw udev rules, per-pad DS MAC, SET_REPORT acks

Root-cause fixes for "rumble + adaptive triggers never work with Linux hosts"
(the capture code itself was proven good on-hardware — see the new tests):

* 60-punktfunk.rules now grants the `input` group the VIRTUAL pads' hidraw
  nodes (DS/Edge/DS4/Switch/Deck/SC). Steam/SDL drive DualSense adaptive
  triggers, lightbar, and player LEDs exclusively over hidraw — and Steam
  without hidraw demotes a PlayStation pad to a generic evdev device, losing
  its rumble handling too. Coverage no longer depends on the distro's
  steam-devices rules + logind's active-seat uaccess ACL (which a headless/
  dedicated streaming session never gets). Verified live: nodes now come up
  root:input 0660.

* Per-pad MAC in the DualSense (0x09) and DS4 (0x12) pairing feature replies:
  hid-playstation adopts the MAC as the HID uniq and SDL/Steam dedup
  controllers by that serial — identical MACs made a second virtual pad read
  as the first one re-connecting over another transport.

* DualSense/DS4 UHID backends now ack UHID_SET_REPORT (err=0) instead of
  ignoring it, so a SET_REPORT writer no longer blocks on the kernel's 5 s
  timeout.

* New #[ignore] on-box tests play the GAME's role against a real kernel and
  pin the full feedback surface (all green on real hw): DualSense evdev-FF +
  raw hidraw output report (rumble/lightbar/LEDs/both trigger blocks verbatim,
  per-pad uniq), uinput X-Box FF upload→pump→stop-on-erase, and usbip Deck
  0xEB rumble via the controller interface (idle interfaces ACK silently,
  like real hardware).

Windows note: the UMDF driver keeps its own pairing blob copies — the shared-
MAC dedup hazard exists there too and needs a driver-side follow-up.

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

crates/punktfunk-host/src/inject/linux/dualsense.rs

@@ -13,9 +13,9 @@
 //! UMDF-driver backend; this module is just the `/dev/uhid` plumbing around it.
 
 use super::dualsense_proto::{
-    edge_paddle_bits, parse_ds_output, serialize_state, DsFeedback, DsState, DS_EDGE_PRODUCT,
-    DS_FEATURE_CALIBRATION, DS_FEATURE_FIRMWARE, DS_FEATURE_PAIRING, DS_INPUT_REPORT_LEN,
-    DS_PRODUCT, DS_TOUCH_H, DS_TOUCH_W, DS_VENDOR, DUALSENSE_EDGE_RDESC, DUALSENSE_RDESC,
+    ds_pairing_reply, edge_paddle_bits, parse_ds_output, serialize_state, DsFeedback, DsState,
+    DS_EDGE_PRODUCT, DS_FEATURE_CALIBRATION, DS_FEATURE_FIRMWARE, DS_INPUT_REPORT_LEN, DS_PRODUCT,
+    DS_TOUCH_H, DS_TOUCH_W, DS_VENDOR, DUALSENSE_EDGE_RDESC, DUALSENSE_RDESC,
 };
 use crate::inject::uhid_manager::{PadFeedback, PadProto, UhidManager};
 use anyhow::{Context, Result};
@@ -33,6 +33,8 @@ const UHID_GET_REPORT: u32 = 9;
 const UHID_GET_REPORT_REPLY: u32 = 10;
 const UHID_CREATE2: u32 = 11;
 const UHID_INPUT2: u32 = 12;
+const UHID_SET_REPORT: u32 = 13;
+const UHID_SET_REPORT_REPLY: u32 = 14;
 const HID_MAX_DESCRIPTOR_SIZE: usize = 4096;
 const UHID_EVENT_SIZE: usize = 4 + 4372; // type + union (create2)
 const BUS_USB: u16 = 0x03;
@@ -106,6 +108,9 @@ impl DualSensePad {
         Ok(ds)
     }
 
+    /// Send UHID_CREATE2 under `id`'s identity. The uniq written here is cosmetic:
+    /// `hid-playstation` replaces it with the MAC from the pairing feature report (see
+    /// [`ds_pairing_reply`]) as soon as it binds.
     fn send_create2(&mut self, index: u8, id: &DsUhidIdentity) -> Result<()> {
         let mut ev = [0u8; UHID_EVENT_SIZE];
         ev[0..4].copy_from_slice(&UHID_CREATE2.to_ne_bytes());
@@ -161,15 +166,25 @@ impl DualSensePad {
                 UHID_GET_REPORT => {
                     // uhid_get_report_req: id u32 [4..8], rnum u8 [8].
                     let id = u32::from_ne_bytes([ev[4], ev[5], ev[6], ev[7]]);
+                    // Per-pad MAC: hid-playstation adopts it as the HID uniq, and SDL/Steam
+                    // dedup controllers by that serial (see `ds_pairing_reply`).
+                    let pairing = ds_pairing_reply(pad);
                     let data: &[u8] = match ev[8] {
                         0x05 => DS_FEATURE_CALIBRATION,
-                        0x09 => DS_FEATURE_PAIRING,
+                        0x09 => &pairing,
                         0x20 => DS_FEATURE_FIRMWARE,
                         _ => &[],
                     };
                     let _ = self.reply_get_report(id, data);
                 }
-                _ => {} // Start/Stop/Open/Close/SetReport — ignore
+                UHID_SET_REPORT => {
+                    // Ack (err=0) so a SET_REPORT writer doesn't block on the kernel's 5 s
+                    // timeout. Nothing to parse: every known DualSense writer sends its feedback
+                    // as OUTPUT reports (handled above), never SET_REPORT.
+                    let id = u32::from_ne_bytes([ev[4], ev[5], ev[6], ev[7]]);
+                    let _ = self.reply_set_report(id);
+                }
+                _ => {} // Start/Stop/Open/Close — ignore
             }
         }
         fb
@@ -189,6 +204,18 @@ impl DualSensePad {
             .context("write UHID_GET_REPORT_REPLY")?;
         Ok(())
     }
+
+    fn reply_set_report(&mut self, id: u32) -> Result<()> {
+        let mut ev = [0u8; UHID_EVENT_SIZE];
+        ev[0..4].copy_from_slice(&UHID_SET_REPORT_REPLY.to_ne_bytes());
+        // uhid_set_report_reply_req: id u32 [4..8], err u16 [8..10].
+        ev[4..8].copy_from_slice(&id.to_ne_bytes());
+        ev[8..10].copy_from_slice(&0u16.to_ne_bytes()); // err 0 (ack)
+        self.fd
+            .write_all(&ev)
+            .context("write UHID_SET_REPORT_REPLY")?;
+        Ok(())
+    }
 }
 
 impl Drop for DualSensePad {
@@ -369,3 +396,257 @@ impl PadProto for DsEdgeLinuxProto {
 /// All virtual DualSense Edge pads of a session — `PUNKTFUNK_GAMEPAD=edge`, or the per-pad kind a
 /// client declares for a paddle-bearing physical controller.
 pub type DualSenseEdgeManager = UhidManager<DsEdgeLinuxProto>;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use punktfunk_core::quic::HidOutput;
+    use std::os::unix::io::AsRawFd;
+    use std::time::{Duration, Instant};
+
+    /// evdev nodes whose input-device name contains `name`: (full name, /dev/input/eventN).
+    fn find_nodes(name: &str) -> Vec<(String, String)> {
+        let s = std::fs::read_to_string("/proc/bus/input/devices").unwrap_or_default();
+        let mut out = Vec::new();
+        let mut cur = String::new();
+        for line in s.lines() {
+            if let Some(n) = line.strip_prefix("N: Name=") {
+                cur = n.trim_matches('"').to_string();
+            } else if let Some(h) = line.strip_prefix("H: Handlers=") {
+                if cur.contains(name) {
+                    if let Some(ev) = h.split_whitespace().find(|t| t.starts_with("event")) {
+                        out.push((cur.clone(), format!("/dev/input/{ev}")));
+                    }
+                }
+            }
+        }
+        out
+    }
+
+    /// Whether the evdev at `node` advertises EV_FF (0x15) — the rumble-capable gamepad node
+    /// (the touchpad / motion / headset siblings don't).
+    fn has_ff(node: &str) -> bool {
+        let Ok(f) = std::fs::OpenOptions::new().read(true).open(node) else {
+            return false;
+        };
+        let mut bits = [0u8; 8];
+        // EVIOCGBIT(0, 8): the device's event-type bitmap.
+        let req: libc::c_ulong = (2 << 30) | (8 << 16) | (0x45 << 8) | 0x20;
+        // SAFETY: EVIOCGBIT(0) copies at most 8 bytes (EV_MAX/8 < 8) into the live `bits` buffer
+        // behind the valid evdev fd `f`; the kernel never writes past the ioctl's size argument.
+        let rc = unsafe { libc::ioctl(f.as_raw_fd(), req, bits.as_mut_ptr()) };
+        rc >= 0 && (bits[0x15 / 8] >> (0x15 % 8)) & 1 == 1
+    }
+
+    /// Upload an FF_RUMBLE effect on `node` and play it, exactly like SDL's evdev haptic backend.
+    /// Returns the OPEN fd with the id — closing the fd erases the process's effects (stopping
+    /// the rumble), so the caller must hold it while asserting.
+    fn evdev_rumble(node: &str, strong: u16, weak: u16) -> std::io::Result<(std::fs::File, i16)> {
+        use std::io::Write as _;
+        let mut f = std::fs::OpenOptions::new()
+            .read(true)
+            .write(true)
+            .open(node)?;
+        // struct ff_effect (48 B): type u16, id s16, direction u16, trigger, replay{len,delay},
+        // pad to 16, union (ff_rumble_effect { strong, weak }).
+        let mut eff = [0u8; 48];
+        eff[0..2].copy_from_slice(&0x50u16.to_ne_bytes()); // FF_RUMBLE
+        eff[2..4].copy_from_slice(&(-1i16).to_ne_bytes()); // id: kernel assigns
+        eff[10..12].copy_from_slice(&5000u16.to_ne_bytes()); // replay.length ms
+        eff[16..18].copy_from_slice(&strong.to_ne_bytes());
+        eff[18..20].copy_from_slice(&weak.to_ne_bytes());
+        // EVIOCSFF = _IOW('E', 0x80, struct ff_effect)
+        let req: libc::c_ulong = (1 << 30) | (48 << 16) | (0x45 << 8) | 0x80;
+        // SAFETY: EVIOCSFF reads/writes the 48-byte ff_effect behind the valid fd `f`; `eff` is
+        // exactly sizeof(struct ff_effect) and outlives the synchronous call.
+        let rc = unsafe { libc::ioctl(f.as_raw_fd(), req, eff.as_mut_ptr()) };
+        if rc < 0 {
+            return Err(std::io::Error::last_os_error());
+        }
+        let id = i16::from_ne_bytes([eff[2], eff[3]]);
+        // struct input_event (24 B on 64-bit): timeval 16, type u16, code u16, value s32.
+        let mut ev = [0u8; 24];
+        ev[16..18].copy_from_slice(&0x15u16.to_ne_bytes()); // EV_FF
+        ev[18..20].copy_from_slice(&(id as u16).to_ne_bytes());
+        ev[20..24].copy_from_slice(&1i32.to_ne_bytes()); // play
+        f.write_all(&ev)?;
+        Ok((f, id))
+    }
+
+    /// `(HID_NAME, HID_UNIQ, /dev/hidrawN)` for every hidraw class device.
+    fn hidraw_devices() -> Vec<(String, String, String)> {
+        let mut out = Vec::new();
+        let Ok(dir) = std::fs::read_dir("/sys/class/hidraw") else {
+            return out;
+        };
+        for e in dir.flatten() {
+            let ue = std::fs::read_to_string(e.path().join("device/uevent")).unwrap_or_default();
+            let field = |k: &str| {
+                ue.lines()
+                    .find_map(|l| l.strip_prefix(k))
+                    .unwrap_or_default()
+                    .to_string()
+            };
+            out.push((
+                field("HID_NAME="),
+                field("HID_UNIQ="),
+                format!("/dev/{}", e.file_name().to_string_lossy()),
+            ));
+        }
+        out
+    }
+
+    /// Service `pad` for `ms`, accumulating every captured feedback pass (all rumble levels in
+    /// order + all rich events) while keeping the input heartbeat going.
+    fn collect(pad: &mut DualSensePad, st: &DsState, ms: u64) -> (Vec<(u16, u16)>, Vec<HidOutput>) {
+        let start = Instant::now();
+        let (mut levels, mut hidout) = (Vec::new(), Vec::<HidOutput>::new());
+        while start.elapsed() < Duration::from_millis(ms) {
+            let fb = pad.service(0);
+            levels.extend(fb.rumble);
+            hidout.extend(fb.hidout);
+            let _ = pad.write_state(st);
+            std::thread::sleep(Duration::from_millis(4));
+        }
+        (levels, hidout)
+    }
+
+    /// On-box proof of the full Linux feedback surface, playing the GAME's role against a real
+    /// kernel: chain A drives rumble through evdev force feedback (`hid-playstation`'s ff-memless
+    /// → UHID_OUTPUT — what SDL/Steam fall back to without hidraw); chain B writes a raw DS5
+    /// output report to the pad's hidraw node (SDL/Steam's real path, and the ONLY way adaptive
+    /// triggers can arrive) and expects rumble + lightbar + player LEDs + both trigger blocks
+    /// back verbatim. Also pins the per-pad pairing MAC: two pads must present distinct uniqs or
+    /// SDL/Steam dedup them into one controller.
+    #[test]
+    #[ignore = "creates real /dev/uhid devices; needs hid-playstation, the input group, and the 60-punktfunk.rules hidraw rules"]
+    fn feedback_flows_via_evdev_ff_and_hidraw() {
+        let mut pad0 = DualSensePad::open(0, &DsUhidIdentity::dualsense()).expect("open pad 0");
+        let mut pad1 = DualSensePad::open(1, &DsUhidIdentity::dualsense()).expect("open pad 1");
+        let st = DsState::neutral();
+        // Let hid-playstation complete its GET_REPORT handshakes and register input devices.
+        let start = Instant::now();
+        while start.elapsed() < Duration::from_millis(1500) {
+            let _ = pad0.service(0);
+            let _ = pad1.service(1);
+            let _ = pad0.write_state(&st);
+            let _ = pad1.write_state(&st);
+            std::thread::sleep(Duration::from_millis(4));
+        }
+        let nodes = find_nodes("Punktfunk DualSense 0");
+        assert!(
+            !nodes.is_empty(),
+            "hid-playstation did not bind the uhid device"
+        );
+        let ff_node = nodes
+            .iter()
+            .map(|(_, n)| n.as_str())
+            .find(|n| has_ff(n))
+            .expect("no FF-capable evdev among the pad's input devices");
+
+        // Per-pad MAC: hid-playstation adopts the pairing-report MAC as HID_UNIQ; the two pads
+        // must differ (the SDL/Steam serial-dedup regression, see `ds_pairing_reply`).
+        let hidraws = hidraw_devices();
+        let uniq = |name: &str| {
+            hidraws
+                .iter()
+                .find(|(n, _, _)| n == name)
+                .map(|(_, u, _)| u.clone())
+                .unwrap_or_else(|| panic!("no hidraw for {name} in {hidraws:?}"))
+        };
+        assert_ne!(
+            uniq("Punktfunk DualSense 0"),
+            uniq("Punktfunk DualSense 1"),
+            "pads share one pairing MAC — SDL/Steam will dedup them into one controller"
+        );
+
+        // ---- Chain A: evdev force feedback ----
+        let (ff_fd, _) = evdev_rumble(ff_node, 0xC000, 0x4000).expect("EVIOCSFF/play");
+        let (levels, _) = collect(&mut pad0, &st, 1000);
+        assert!(
+            levels.iter().any(|&(l, h)| l > 0 || h > 0),
+            "evdev FF rumble never surfaced as UHID_OUTPUT: {levels:?}"
+        );
+        drop(ff_fd); // closing erases the effect: the stop must surface too
+        let (levels, _) = collect(&mut pad0, &st, 800);
+        assert!(
+            levels.contains(&(0, 0)),
+            "erase-on-close never produced a rumble stop: {levels:?}"
+        );
+
+        // ---- Chain B: raw DS5 output report over hidraw ----
+        let hr = hidraws
+            .iter()
+            .find(|(n, _, _)| n == "Punktfunk DualSense 0")
+            .map(|(_, _, d)| d.clone())
+            .unwrap();
+        let mut rep = [0u8; 48];
+        rep[0] = 0x02; // USB output report id
+        rep[1] = 0x03 | 0x04 | 0x08; // flag0: compat vibration + haptics select + R2 + L2
+        rep[2] = 0x04 | 0x10; // flag1: lightbar + player LEDs
+        rep[3] = 0x60; // motor right (high)
+        rep[4] = 0xA0; // motor left (low)
+        rep[11] = 0x21; // R2 trigger block: weapon mode + params
+        rep[12] = 0x04;
+        rep[13] = 0x07;
+        rep[22] = 0x26; // L2 trigger block: vibration mode + params
+        rep[23] = 0x02;
+        rep[44] = 0x04; // player LED middle
+        rep[45] = 0x10;
+        rep[46] = 0x20;
+        rep[47] = 0x30;
+        std::fs::OpenOptions::new()
+            .write(true)
+            .open(&hr)
+            .and_then(|mut f| std::io::Write::write_all(&mut f, &rep))
+            .unwrap_or_else(|e| {
+                panic!(
+                    "cannot write {hr} as this user ({e}) — Steam/SDL would be equally blocked; \
+                     are the 60-punktfunk.rules hidraw rules installed?"
+                )
+            });
+        let (levels, hidout) = collect(&mut pad0, &st, 1000);
+        assert!(
+            levels.contains(&(0xA000, 0x6000)),
+            "hidraw rumble did not surface: {levels:?}"
+        );
+        let triggers: Vec<_> = hidout
+            .iter()
+            .filter_map(|h| match h {
+                HidOutput::Trigger { which, effect, .. } => Some((*which, effect.clone())),
+                _ => None,
+            })
+            .collect();
+        assert_eq!(
+            triggers.len(),
+            2,
+            "expected both trigger blocks: {hidout:?}"
+        );
+        assert!(
+            triggers.contains(&(1, rep[11..22].to_vec())),
+            "R2 block not verbatim"
+        );
+        assert!(
+            triggers.contains(&(0, rep[22..33].to_vec())),
+            "L2 block not verbatim"
+        );
+        assert!(
+            hidout.iter().any(|h| matches!(
+                h,
+                HidOutput::Led {
+                    r: 0x10,
+                    g: 0x20,
+                    b: 0x30,
+                    ..
+                }
+            )),
+            "lightbar not surfaced: {hidout:?}"
+        );
+        assert!(
+            hidout
+                .iter()
+                .any(|h| matches!(h, HidOutput::PlayerLeds { bits: 0x04, .. })),
+            "player LEDs not surfaced: {hidout:?}"
+        );
+    }
+}

crates/punktfunk-host/src/inject/linux/dualshock4.rs

@@ -33,6 +33,8 @@ const UHID_GET_REPORT: u32 = 9;
 const UHID_GET_REPORT_REPLY: u32 = 10;
 const UHID_CREATE2: u32 = 11;
 const UHID_INPUT2: u32 = 12;
+const UHID_SET_REPORT: u32 = 13;
+const UHID_SET_REPORT_REPLY: u32 = 14;
 const HID_MAX_DESCRIPTOR_SIZE: usize = 4096;
 const UHID_EVENT_SIZE: usize = 4 + 4372; // type + union (create2)
 const BUS_USB: u16 = 0x03;
@@ -46,6 +48,17 @@ const BUS_USB: u16 = 0x03;
 const DS4_FEATURE_PAIRING: &[u8] = &[ // report 0x12 (MAC at bytes 1..7, LE → DE:AD:BE:EF:00:01)
     0x12, 0x01, 0x00, 0xEF, 0xBE, 0xAD, 0xDE, 0x08, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 ];
+
+/// The pairing reply for wire pad `pad`: [`DS4_FEATURE_PAIRING`] with the MAC's low octet offset
+/// by the pad index — same per-pad-serial contract as the DualSense's
+/// [`ds_pairing_reply`](super::dualsense_proto::ds_pairing_reply): the kernel adopts the MAC as
+/// the HID uniq, and SDL/Steam dedup controllers by that serial.
+fn ds4_pairing_reply(pad: u8) -> [u8; 16] {
+    let mut r = [0u8; 16];
+    r.copy_from_slice(DS4_FEATURE_PAIRING);
+    r[1] = r[1].wrapping_add(pad); // MAC lives at bytes 1..7, LSB first
+    r
+}
 #[rustfmt::skip]
 const DS4_FEATURE_CALIBRATION: &[u8] = &[ // report 0x02 (IMU calibration; all signed le16 words)
     0x02,
@@ -204,9 +217,9 @@ impl DualShock4Pad {
     /// Service the device, non-blocking: answer the kernel's feature-report GET_REPORTs (pairing /
     /// calibration / firmware — the pairing reply is required during `hid-playstation` init, or no
     /// input devices appear) and parse any HID OUTPUT reports (rumble / lightbar) into a
-    /// [`Ds4Feedback`]. Call frequently — especially right after [`open`] so the init handshake
-    /// completes.
-    pub fn service(&mut self) -> Ds4Feedback {
+    /// [`Ds4Feedback`] for pad `pad`. Call frequently — especially right after [`open`] so the
+    /// init handshake completes.
+    pub fn service(&mut self, pad: u8) -> Ds4Feedback {
         let mut fb = Ds4Feedback::default();
         let mut ev = [0u8; UHID_EVENT_SIZE];
         while let Ok(n) = self.fd.read(&mut ev) {
@@ -223,15 +236,22 @@ impl DualShock4Pad {
                 UHID_GET_REPORT => {
                     // uhid_get_report_req: id u32 [4..8], rnum u8 [8].
                     let id = u32::from_ne_bytes([ev[4], ev[5], ev[6], ev[7]]);
+                    let pairing = ds4_pairing_reply(pad);
                     let data: &[u8] = match ev[8] {
-                        0x12 => DS4_FEATURE_PAIRING,
+                        0x12 => &pairing,
                         0x02 => DS4_FEATURE_CALIBRATION,
                         0xA3 => DS4_FEATURE_FIRMWARE,
                         _ => &[],
                     };
                     let _ = self.reply_get_report(id, data);
                 }
-                _ => {} // Start/Stop/Open/Close/SetReport — ignore
+                UHID_SET_REPORT => {
+                    // Ack (err=0) so a SET_REPORT writer doesn't block on the kernel's 5 s
+                    // timeout; DS4 feedback arrives as OUTPUT reports (handled above).
+                    let id = u32::from_ne_bytes([ev[4], ev[5], ev[6], ev[7]]);
+                    let _ = self.reply_set_report(id);
+                }
+                _ => {} // Start/Stop/Open/Close — ignore
             }
         }
         fb
@@ -251,6 +271,18 @@ impl DualShock4Pad {
             .context("write UHID_GET_REPORT_REPLY")?;
         Ok(())
     }
+
+    fn reply_set_report(&mut self, id: u32) -> Result<()> {
+        let mut ev = [0u8; UHID_EVENT_SIZE];
+        ev[0..4].copy_from_slice(&UHID_SET_REPORT_REPLY.to_ne_bytes());
+        // uhid_set_report_reply_req: id u32 [4..8], err u16 [8..10].
+        ev[4..8].copy_from_slice(&id.to_ne_bytes());
+        ev[8..10].copy_from_slice(&0u16.to_ne_bytes()); // err 0 (ack)
+        self.fd
+            .write_all(&ev)
+            .context("write UHID_SET_REPORT_REPLY")?;
+        Ok(())
+    }
 }
 
 impl Drop for DualShock4Pad {
@@ -338,7 +370,7 @@ impl PadProto for Ds4LinuxProto {
     /// 0xCA plane, the lightbar as a 0xCD `Led` event (a DS4 has no player LEDs / adaptive
     /// triggers).
     fn service(&self, pad: &mut DualShock4Pad, idx: u8) -> PadFeedback {
-        let fb = pad.service();
+        let fb = pad.service(idx);
         PadFeedback {
             rumble: fb.rumble,
             hidout: fb
@@ -375,4 +407,16 @@ mod tests {
         assert_eq!(DS4_FEATURE_FIRMWARE.len(), 49);
         assert_eq!(DS4_FEATURE_FIRMWARE[0], 0xA3);
     }
+
+    /// The pairing reply keeps the report id and differs across pads ONLY in the MAC low octet —
+    /// distinct serials so SDL/Steam never dedup two virtual pads into one controller.
+    #[test]
+    fn pairing_reply_mac_is_per_pad() {
+        assert_eq!(ds4_pairing_reply(0).as_slice(), DS4_FEATURE_PAIRING);
+        let (a, b) = (ds4_pairing_reply(1), ds4_pairing_reply(2));
+        assert_eq!(a[0], 0x12); // report id untouched
+        assert_eq!(a[1], DS4_FEATURE_PAIRING[1].wrapping_add(1));
+        assert_eq!(b[1], DS4_FEATURE_PAIRING[1].wrapping_add(2));
+        assert_eq!(a[2..], b[2..]); // everything but the low octet identical
+    }
 }

crates/punktfunk-host/src/inject/linux/gamepad.rs

@@ -625,3 +625,105 @@ impl GamepadManager {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::time::Duration;
+
+    /// The FF-capable evdev node whose input-device name contains `name`.
+    fn find_ff_node(name: &str) -> Option<String> {
+        let s = std::fs::read_to_string("/proc/bus/input/devices").unwrap_or_default();
+        let mut cur = String::new();
+        let mut node = None;
+        for line in s.lines() {
+            if let Some(n) = line.strip_prefix("N: Name=") {
+                cur = n.trim_matches('"').to_string();
+            } else if let Some(h) = line.strip_prefix("H: Handlers=") {
+                if cur.contains(name) {
+                    node = h
+                        .split_whitespace()
+                        .find(|t| t.starts_with("event"))
+                        .map(|ev| format!("/dev/input/{ev}"));
+                }
+            } else if line.starts_with("B: FF=")
+                && cur.contains(name)
+                && node.is_some()
+                && !line.trim_end().ends_with("FF=0")
+            {
+                return node;
+            }
+        }
+        node
+    }
+
+    /// Upload + play an FF_RUMBLE like SDL's evdev haptic backend. Returns the OPEN fd (closing
+    /// it erases the process's effects, stopping the rumble) with the kernel-assigned id.
+    /// NOTE: EVIOCSFF BLOCKS until the uinput owner answers UI_FF_UPLOAD — the caller must be a
+    /// separate thread from the one running [`VirtualPad::pump_ff`], exactly like a real game vs
+    /// the host input loop.
+    fn evdev_rumble(node: &str, strong: u16, weak: u16) -> std::io::Result<(std::fs::File, i16)> {
+        use std::io::Write as _;
+        let mut f = std::fs::OpenOptions::new()
+            .read(true)
+            .write(true)
+            .open(node)?;
+        let mut eff = [0u8; 48]; // struct ff_effect; union (rumble magnitudes) at offset 16
+        eff[0..2].copy_from_slice(&FF_RUMBLE.to_ne_bytes());
+        eff[2..4].copy_from_slice(&(-1i16).to_ne_bytes()); // id: kernel assigns
+        eff[10..12].copy_from_slice(&5000u16.to_ne_bytes()); // replay.length ms
+        eff[16..18].copy_from_slice(&strong.to_ne_bytes());
+        eff[18..20].copy_from_slice(&weak.to_ne_bytes());
+        // EVIOCSFF = _IOW('E', 0x80, struct ff_effect)
+        let req: libc::c_ulong = (1 << 30) | (48 << 16) | (0x45 << 8) | 0x80;
+        // SAFETY: EVIOCSFF reads/writes the 48-byte ff_effect behind the valid fd `f`; `eff` is
+        // exactly sizeof(struct ff_effect) and outlives the synchronous call.
+        let rc = unsafe { libc::ioctl(f.as_raw_fd(), req, eff.as_mut_ptr()) };
+        if rc < 0 {
+            return Err(std::io::Error::last_os_error());
+        }
+        let id = i16::from_ne_bytes([eff[2], eff[3]]);
+        let mut ev = [0u8; 24]; // struct input_event: timeval 16, type u16, code u16, value s32
+        ev[16..18].copy_from_slice(&EV_FF.to_ne_bytes());
+        ev[18..20].copy_from_slice(&(id as u16).to_ne_bytes());
+        ev[20..24].copy_from_slice(&1i32.to_ne_bytes()); // play
+        f.write_all(&ev)?;
+        Ok((f, id))
+    }
+
+    /// On-box proof of the uinput FF back-channel, playing the GAME's role: an evdev FF_RUMBLE
+    /// upload+play against the virtual X-Box 360 pad must surface through `pump_ff` (the
+    /// EV_UINPUT UI_FF_UPLOAD protocol) — the path every `auto`-kind session's rumble rides on
+    /// Linux — and erasing the effect (fd close) must surface the stop.
+    #[test]
+    #[ignore = "creates a real /dev/uinput device; needs the input group"]
+    fn ff_upload_reaches_pump_and_stops_on_erase() {
+        let mut pad = VirtualPad::create(0, PadIdentity::xbox360()).expect("create uinput pad");
+        std::thread::sleep(Duration::from_millis(700)); // let udev settle the node
+        let node = find_ff_node("Microsoft X-Box 360 pad").expect("no X-Box 360 evdev node");
+        let game = std::thread::spawn(move || {
+            let r = evdev_rumble(&node, 0xC000, 0x4000);
+            std::thread::sleep(Duration::from_millis(1200)); // hold the effect, then erase
+            r.expect("EVIOCSFF/play (fd held meanwhile)");
+        });
+        let start = Instant::now();
+        let mut seen = Vec::new();
+        while start.elapsed() < Duration::from_millis(2500) {
+            if let Some(mix) = pad.pump_ff() {
+                seen.push(mix);
+            }
+            std::thread::sleep(Duration::from_millis(4));
+        }
+        game.join().unwrap();
+        // Requested magnitudes scaled by the 0xFFFF default gain (>> 16).
+        assert!(
+            seen.contains(&(0xBFFF, 0x3FFF)),
+            "evdev FF rumble never surfaced through pump_ff: {seen:?}"
+        );
+        assert_eq!(
+            seen.last(),
+            Some(&(0, 0)),
+            "erase-on-close never produced a stop mix: {seen:?}"
+        );
+    }
+}

crates/punktfunk-host/src/inject/linux/steam_usbip.rs

@@ -730,4 +730,74 @@ mod tests {
             "device not torn down on drop"
         );
     }
+
+    /// On-box smoke test (needs root + `vhci_hcd`): rumble the attached virtual Deck exactly like
+    /// Steam does — a `0xEB` feature SET_REPORT on the hid-steam hidraw node — and confirm
+    /// [`SteamDeckUsbip::service`] surfaces `(left, right)` for the 0xCA plane. The Deck presents
+    /// 3 interfaces (0 mouse / 1 kbd / 2 controller); only the CONTROLLER interface's EP0 handler
+    /// parses feedback (the idle interfaces ACK silently, like real hardware), and Steam filters
+    /// on interface 2 — so the write must land there. `#[ignore]`d in CI.
+    #[test]
+    #[ignore = "attaches a real vhci_hcd device; needs root + vhci_hcd"]
+    fn usbip_deck_rumble_flows_via_controller_interface() {
+        use super::super::steam_proto::ID_TRIGGER_RUMBLE_CMD;
+        ensure_modules();
+        let mut pad = SteamDeckUsbip::open(0).expect("open SteamDeckUsbip (root + vhci_hcd?)");
+        let st = SteamState::from_gamepad(0, 0, 0, 0, 0, 0, 0);
+        let start = Instant::now();
+        while start.elapsed() < Duration::from_millis(1500) {
+            pad.write_state(&st);
+            let _ = pad.service();
+            std::thread::sleep(Duration::from_millis(8));
+        }
+        // The hid-steam hidraw node on USB interface 2 (bInterfaceNumber is the HID device's
+        // parent attribute).
+        let node = std::fs::read_dir("/sys/class/hidraw")
+            .expect("/sys/class/hidraw")
+            .flatten()
+            .find_map(|e| {
+                let ue =
+                    std::fs::read_to_string(e.path().join("device/uevent")).unwrap_or_default();
+                let iface = std::fs::read_to_string(e.path().join("device/../bInterfaceNumber"))
+                    .ok()
+                    .and_then(|s| u8::from_str_radix(s.trim(), 16).ok());
+                (ue.lines().any(|l| l == "DRIVER=hid-steam") && iface == Some(2))
+                    .then(|| format!("/dev/{}", e.file_name().to_string_lossy()))
+            })
+            .expect("no hid-steam hidraw on interface 2");
+        let f = std::fs::OpenOptions::new()
+            .read(true)
+            .write(true)
+            .open(&node)
+            .expect("open hidraw");
+        // steam_haptic_rumble: [report-id 0, 0xEB, len 9, 0, intensity(2), left(2), right(2), gain(2)]
+        let mut buf = [0u8; 12];
+        buf[1] = ID_TRIGGER_RUMBLE_CMD;
+        buf[2] = 0x09;
+        buf[6..8].copy_from_slice(&0xC000u16.to_le_bytes());
+        buf[8..10].copy_from_slice(&0x4000u16.to_le_bytes());
+        // HIDIOCSFEATURE(12)
+        let req: libc::c_ulong =
+            (3 << 30) | ((buf.len() as libc::c_ulong) << 16) | (0x48 << 8) | 0x06;
+        // SAFETY: HIDIOCSFEATURE reads the 12-byte report from the live `buf` behind the valid
+        // hidraw fd `f`; the length is encoded in the request, so nothing is written past it.
+        let rc = unsafe { libc::ioctl(f.as_raw_fd(), req, buf.as_mut_ptr()) };
+        assert!(
+            rc >= 0,
+            "HIDIOCSFEATURE: {}",
+            std::io::Error::last_os_error()
+        );
+        let start = Instant::now();
+        let mut got = None;
+        while got.is_none() && start.elapsed() < Duration::from_millis(1500) {
+            got = pad.service().rumble;
+            pad.write_state(&st);
+            std::thread::sleep(Duration::from_millis(8));
+        }
+        assert_eq!(
+            got,
+            Some((0xC000, 0x4000)),
+            "Deck rumble never surfaced from the interface-2 SET_REPORT"
+        );
+    }
 }

crates/punktfunk-host/src/inject/proto/dualsense_proto.rs

@@ -42,6 +42,18 @@ pub const DS_FEATURE_FIRMWARE: &[u8] = &[ // report 0x20 (firmware info / build
     0x14, 0x00, 0x00, 0x00, 0x0B, 0x00, 0x01, 0x00, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 ];
 
+/// The pairing reply (report `0x09`) for wire pad `pad`: [`DS_FEATURE_PAIRING`] with the MAC's low
+/// octet offset by the pad index. The MAC must be **unique per pad**: `hid-playstation` adopts it
+/// as the HID `uniq` (replacing whatever uniq the device was created with), and SDL/Steam dedup
+/// controllers by that serial — with identical MACs a second virtual pad reads as the *first* pad
+/// re-appearing over another transport and is merged/ignored.
+pub fn ds_pairing_reply(pad: u8) -> [u8; 20] {
+    let mut r = [0u8; 20];
+    r.copy_from_slice(DS_FEATURE_PAIRING);
+    r[1] = r[1].wrapping_add(pad); // MAC lives at bytes 1..7, LSB first
+    r
+}
+
 /// Sony DualSense USB HID report descriptor (273 bytes), verbatim from inputtino — the exact
 /// descriptor `hid-playstation` (Linux) / `hidclass` (Windows) parses to bind a DualSense.
 #[rustfmt::skip]
@@ -923,4 +935,16 @@ mod tests {
         assert!(fb.rumble.is_none());
         assert!(fb.hidout.is_empty());
     }
+
+    /// The pairing reply keeps the report id and differs across pads ONLY in the MAC low octet —
+    /// distinct serials so SDL/Steam never dedup two virtual pads into one controller.
+    #[test]
+    fn pairing_reply_mac_is_per_pad() {
+        assert_eq!(ds_pairing_reply(0).as_slice(), DS_FEATURE_PAIRING);
+        let (a, b) = (ds_pairing_reply(1), ds_pairing_reply(2));
+        assert_eq!(a[0], 0x09); // report id untouched
+        assert_eq!(a[1], DS_FEATURE_PAIRING[1].wrapping_add(1));
+        assert_eq!(b[1], DS_FEATURE_PAIRING[1].wrapping_add(2));
+        assert_eq!(a[2..], b[2..]); // everything but the low octet identical
+    }
 }

packaging/bazzite/README.md

@@ -207,11 +207,14 @@ ujust add-user-to-input-group      # NOT `usermod` on Bazzite (see the note abov
 sudo udevadm control --reload-rules && sudo udevadm trigger
 ```
 
-The rule contents, for reference:
+The core rule contents, for reference (the full file additionally grants the `input` group access
+to the vhci attach files and to the hidraw nodes of the virtual pads the host creates — Steam/SDL
+need hidraw to send a DualSense's adaptive-trigger/lightbar feedback and reliable rumble):
 
 ```
 KERNEL=="uinput", SUBSYSTEM=="misc", OPTIONS+="static_node=uinput", GROUP="input", MODE="0660", TAG+="uaccess"
 KERNEL=="uhid",   SUBSYSTEM=="misc", OPTIONS+="static_node=uhid",   GROUP="input", MODE="0660", TAG+="uaccess"
+KERNEL=="hidraw*", KERNELS=="*054C:0CE6*", GROUP="input", MODE="0660", TAG+="uaccess"   # + 0DF2/09CC/2009/1205/1102
 ```
 
 ---

scripts/60-punktfunk.rules

@@ -17,3 +17,24 @@ KERNEL=="uhid", SUBSYSTEM=="misc", OPTIONS+="static_node=uhid", GROUP="input", M
 # are root-only by default while the host runs as a user service — grant the `input`
 # group write when vhci_hcd appears (module autoload: modules-load.d/punktfunk.conf).
 ACTION=="add", SUBSYSTEM=="platform", KERNEL=="vhci_hcd.*", RUN+="/bin/sh -c 'chgrp input /sys%p/attach /sys%p/detach && chmod 0660 /sys%p/attach /sys%p/detach'"
+
+# hidraw access for the VIRTUAL pads this host creates. Steam/SDL drive a DualSense's rich
+# feedback (adaptive triggers, lightbar, player LEDs) exclusively over hidraw — the kernel has no
+# evdev API for any of it — and Steam without hidraw demotes a PlayStation pad to a generic evdev
+# device, losing its rumble handling too. hidraw nodes are root-only by default; the distro's
+# steam-devices rules + logind's uaccess ACL cover only the active seat session, so a game
+# launched outside it (a headless/dedicated streaming session) is silently feedback-dead.
+# GROUP="input" makes access follow the same group the host itself already requires.
+# KERNELS matches the HID device name (works for UHID devices, which have no USB parent);
+# the ATTRS pair covers the usbip/gadget Deck, which IS a (virtual) USB device.
+# DualSense (054C:0CE6) / DualSense Edge (054C:0DF2) / DualShock 4 (054C:09CC)
+KERNEL=="hidraw*", KERNELS=="*054C:0CE6*", GROUP="input", MODE="0660", TAG+="uaccess"
+KERNEL=="hidraw*", KERNELS=="*054C:0DF2*", GROUP="input", MODE="0660", TAG+="uaccess"
+KERNEL=="hidraw*", KERNELS=="*054C:09CC*", GROUP="input", MODE="0660", TAG+="uaccess"
+# Switch Pro Controller (057E:2009) — SDL's hidapi driver wants hidraw for rumble/LEDs too
+KERNEL=="hidraw*", KERNELS=="*057E:2009*", GROUP="input", MODE="0660", TAG+="uaccess"
+# Steam Deck (28DE:1205) / classic Steam Controller (28DE:1102), UHID and usbip/gadget forms
+KERNEL=="hidraw*", KERNELS=="*28DE:1205*", GROUP="input", MODE="0660", TAG+="uaccess"
+KERNEL=="hidraw*", KERNELS=="*28DE:1102*", GROUP="input", MODE="0660", TAG+="uaccess"
+KERNEL=="hidraw*", ATTRS{idVendor}=="28de", ATTRS{idProduct}=="1205", GROUP="input", MODE="0660", TAG+="uaccess"
+KERNEL=="hidraw*", ATTRS{idVendor}=="28de", ATTRS{idProduct}=="1102", GROUP="input", MODE="0660", TAG+="uaccess"