perf(inject/host): dedup the DualSense HID-output feedback plane (G17)

A game's DualSense output report bundles rumble + lightbar + player-LEDs + adaptive-triggers into one report, so a pad that is merely rumbling re-sends its unchanged lightbar / LED / trigger state on every output report. The managers already dedup rumble, but forwarded every rich `HidOutput` event verbatim — flooding the 0xCD feedback plane to the client during continuous rumble. Add a shared `HidoutDedup` (dualsense_proto, used by both the Linux UHID and Windows UMDF managers) that forwards Led/PlayerLeds/Trigger only on a value change (per side for the two triggers) and always forwards one-shot TrackpadHaptic pulses — mirroring the rumble dedup two lines above and the DS4 backend's lightbar dedup. Reset per pad on create/unplug. Verified on Linux .21 (clippy -D warnings clean, new HidoutDedup unit test + full suite green); Windows .173 with the rest of Phase 3. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-13 14:14:28 +02:00
parent d611645ffc
commit 59fc820226
3 changed files with 134 additions and 5 deletions
@@ -445,10 +445,119 @@ pub fn parse_ds_output(pad: u8, data: &[u8], fb: &mut DsFeedback) {
    }
 }

+/// Per-pad dedup for the DualSense HID-output feedback plane (0xCD). A game's DualSense output report
+/// bundles rumble + lightbar + player-LEDs + adaptive-triggers into one report, so a pad that is
+/// merely *rumbling* re-sends its (unchanged) lightbar / LED / trigger state on every output report.
+/// The managers already dedup rumble; this does the same for the rich [`HidOutput`] feedback so the
+/// 0xCD plane carries only genuine changes. State (`Led` / `PlayerLeds` / `Trigger`) is deduped by
+/// value; a one-shot `TrackpadHaptic` pulse is always forwarded (each pulse must fire).
+#[derive(Clone, Default)]
+pub struct HidoutDedup {
+    led: Option<(u8, u8, u8)>,
+    player_leds: Option<u8>,
+    /// Last-forwarded adaptive-trigger effect per side: `[0]` = L2, `[1]` = R2.
+    trigger: [Option<Vec<u8>>; 2],
+}
+
+impl HidoutDedup {
+    /// Forget all remembered state — call when a pad is created or unplugged so the first feedback
+    /// after a (re)connect is always forwarded.
+    pub fn clear(&mut self) {
+        *self = HidoutDedup::default();
+    }
+
+    /// Whether `h` should be forwarded: `true` for a genuine change (remembering the new value) or a
+    /// one-shot pulse; `false` if it repeats the last-forwarded value for its kind.
+    pub fn should_forward(&mut self, h: &HidOutput) -> bool {
+        match h {
+            HidOutput::Led { r, g, b, .. } => {
+                let v = Some((*r, *g, *b));
+                if self.led == v {
+                    false
+                } else {
+                    self.led = v;
+                    true
+                }
+            }
+            HidOutput::PlayerLeds { bits, .. } => {
+                let v = Some(*bits);
+                if self.player_leds == v {
+                    false
+                } else {
+                    self.player_leds = v;
+                    true
+                }
+            }
+            HidOutput::Trigger { which, effect, .. } => {
+                let slot = (*which as usize).min(1);
+                if self.trigger[slot].as_deref() == Some(effect.as_slice()) {
+                    false
+                } else {
+                    self.trigger[slot] = Some(effect.clone());
+                    true
+                }
+            }
+            // One-shot haptic pulse (Steam voice-coil) — state-less, always fires.
+            HidOutput::TrackpadHaptic { .. } => true,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
    use super::*;

+    /// `HidoutDedup` forwards a value once, drops exact repeats, re-forwards a change, tracks the two
+    /// trigger sides independently, never dedups one-shot haptic pulses, and re-arms after `clear`.
+    #[test]
+    fn hidout_dedup_forwards_only_changes() {
+        let mut d = HidoutDedup::default();
+        let led = |r| HidOutput::Led {
+            pad: 0,
+            r,
+            g: 0,
+            b: 0,
+        };
+        // First value forwards; an exact repeat is dropped; a change forwards again.
+        assert!(d.should_forward(&led(10)));
+        assert!(!d.should_forward(&led(10)));
+        assert!(d.should_forward(&led(20)));
+
+        // Player LEDs dedup on their own field, independent of the lightbar.
+        let pl = |bits| HidOutput::PlayerLeds { pad: 0, bits };
+        assert!(d.should_forward(&pl(0b101)));
+        assert!(!d.should_forward(&pl(0b101)));
+        assert!(!d.should_forward(&led(20))); // lightbar still unchanged
+
+        // The two adaptive triggers (L2=0, R2=1) are tracked separately.
+        let trig = |which, byte| HidOutput::Trigger {
+            pad: 0,
+            which,
+            effect: vec![byte, 0, 0],
+        };
+        assert!(d.should_forward(&trig(0, 1)));
+        assert!(d.should_forward(&trig(1, 1))); // same bytes, other side → still forwards
+        assert!(!d.should_forward(&trig(0, 1)));
+        assert!(d.should_forward(&trig(0, 2))); // L2 effect changed
+
+        // One-shot haptic pulses are never deduped.
+        let haptic = HidOutput::TrackpadHaptic {
+            pad: 0,
+            side: 0,
+            amplitude: 1,
+            period: 2,
+            count: 3,
+        };
+        assert!(d.should_forward(&haptic));
+        assert!(d.should_forward(&haptic));
+
+        // `clear` re-arms every kind.
+        d.clear();
+        assert!(d.should_forward(&led(20)));
+        assert!(d.should_forward(&pl(0b101)));
+        assert!(d.should_forward(&trig(0, 2)));
+    }
+
    /// The Steam dual-pad → DualSense touchpad SPLIT: left pad (surface 1) lands contact 0
    /// on the left half, right pad (surface 2) contact 1 on the right half; y follows the
    /// shared screen convention (top → 0) with no flip; pad clicks set the touchpad-click