Red Bear OS — microkernel OS in Rust, based on Redox

Derivative of Redox OS (https://www.redox-os.org) adding:
- AMD GPU driver (amdgpu) via LinuxKPI compat layer
- ext4 filesystem support (ext4d scheme daemon)
- ACPI fixes for AMD bare metal (x2APIC, DMAR, IVRS, MCFG)
- Custom branding (hostname, os-release, boot identity)

Build system is full upstream Redox with RBOS overlay in local/.
Patches for kernel, base, and relibc are symlinked from local/patches/
and protected from make clean/distclean. Custom recipes live in
local/recipes/ with symlinks into the recipes/ search path.

Build:  make all CONFIG_NAME=redbear-full
Sync:   ./local/scripts/sync-upstream.sh

local/recipes/system/evdevd/source/src/device.rs

@@ -0,0 +1,95 @@
+use std::collections::VecDeque;
+
+use crate::types::{InputEvent, InputId, BUS_VIRTUAL};
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum DeviceKind {
+    Keyboard,
+    Mouse,
+    Touchpad,
+}
+
+pub struct InputDevice {
+    pub id: usize,
+    pub kind: DeviceKind,
+    pub name: String,
+    pub input_id: InputId,
+    pub event_buf: VecDeque<InputEvent>,
+}
+
+impl InputDevice {
+    pub fn new_keyboard(id: usize) -> Self {
+        InputDevice {
+            id,
+            kind: DeviceKind::Keyboard,
+            name: format!("Redox Keyboard {}", id),
+            input_id: InputId {
+                bustype: BUS_VIRTUAL,
+                vendor: 0,
+                product: id as u16,
+                version: 1,
+            },
+            event_buf: VecDeque::new(),
+        }
+    }
+
+    pub fn new_mouse(id: usize) -> Self {
+        InputDevice {
+            id,
+            kind: DeviceKind::Mouse,
+            name: format!("Redox Mouse {}", id),
+            input_id: InputId {
+                bustype: BUS_VIRTUAL,
+                vendor: 0,
+                product: (id + 0x10) as u16,
+                version: 1,
+            },
+            event_buf: VecDeque::new(),
+        }
+    }
+
+    pub fn new_touchpad(id: usize) -> Self {
+        InputDevice {
+            id,
+            kind: DeviceKind::Touchpad,
+            name: format!("Redox Touchpad {}", id),
+            input_id: InputId {
+                bustype: BUS_VIRTUAL,
+                vendor: 0,
+                product: (id + 0x20) as u16,
+                version: 1,
+            },
+            event_buf: VecDeque::new(),
+        }
+    }
+
+    pub fn push_event(&mut self, event: InputEvent) {
+        self.event_buf.push_back(event);
+    }
+
+    pub fn push_events(&mut self, events: &[InputEvent]) {
+        for &ev in events {
+            self.event_buf.push_back(ev);
+        }
+    }
+
+    pub fn pop_bytes(&mut self, buf: &mut [u8]) -> usize {
+        let event_count = buf.len() / InputEvent::SIZE;
+        let mut written = 0;
+        for _ in 0..event_count {
+            match self.event_buf.pop_front() {
+                Some(ev) => {
+                    let bytes = ev.to_bytes();
+                    buf[written..written + InputEvent::SIZE].copy_from_slice(&bytes);
+                    written += InputEvent::SIZE;
+                }
+                None => break,
+            }
+        }
+        written
+    }
+
+    pub fn has_events(&self) -> bool {
+        !self.event_buf.is_empty()
+    }
+}