Input

Input comes from PS/2 controllers and USB HID devices, is merged in the kernel input layer (src/kernel/core/input.cpp), and reaches userspace through per-process event queues — there are no input device files.

PS/2 Keyboard

src/drivers/class/hid/ps2_keyboard.cpp uses ports 0x60/0x64 with scan code set 1:

• 0xE0 extended prefix decodes arrows, Home/End, Delete, Page Up/Down into special characters (0x80-0x88; with shift held, left/right/up/down/Home/End become 0x90-0x95 for selection).
• Modifier tracking (shift/ctrl/alt/capslock), Ctrl+letter control codes, Alt+Space triggers the desktop launcher. Ctrl+C sends SIGINT to the current process only in a terminal/desktop context (input_ctrl_c_to_signal()); while a GUI app is focused the 0x03 control char is delivered instead so apps can bind it (Edit > Copy).
• A 256-byte lock-free ring buffer holds decoded characters; IRQ1 (vector 33).

PS/2 Mouse

src/drivers/class/hid/ps2_mouse.cpp enables the auxiliary device, then runs the IntelliMouse magic sequence (sample rates 200, 100, 80) and reads the device ID:

• ID 3 or 4: 4-byte packets with scroll wheel; otherwise 3-byte packets.
• Packet validation (bit 3), sign extension, Y inversion, scroll accumulation, cursor clamping to the framebuffer; position starts at screen center. IRQ12 (vector 44).

Merging

input_mouse_get_state() merges PS/2 and USB mouse state (USB overrides when connected); input_keyboard_get_char() prefers USB, then PS/2. input_poll() pumps HID polling and key repeat; it runs from the kernel idle loop and from event consumers.

Event Delivery

Two paths, both syscall-based:

Graphical (window manager). Kernel event pumping converts polled input into Event records — mouse move/down/up/scroll, key down/up, window resize/close (include/uapi/event.h) — and pushes them into the window manager's per-process EventQueue (128-slot ring, IRQ-safe spinlock). The WM drains it with SYS_GET_EVENT (blocking or non-blocking, interruptible by fatal signals) and retargets events to client windows with SYS_POST_EVENT, translating screen coordinates to window-local space. The WM registers itself with SYS_GUI_REGISTER_WM; focus is tracked with SYS_GUI_SET_FOCUS.

Client delivery rules (WM → app). Mouse moves are forwarded only to the focused user window while the pointer is inside its client area — except while a client holds a pointer grab. A mouse-down delivered to a client grabs the pointer for that window: until the matching button is released, moves and the release are forwarded to the grabbed window even outside its client area, so in-window drags (sliders, scrollbars, selections) keep working past the frame. The release is likewise delivered outside the client area when a grab is active. Keys go to the focused window; the wheel scrolls WM-side content first and is only forwarded to the client when there is nothing to scroll.

Client Lifecycle Events

The WM posts synthetic lifecycle events so clients never have to poll the registry for interaction state:

Clients use these to clear hover state, stop drags, and redraw sticky overlays; unknown events are ignored by older apps.

Text. SYS_READ on stdin polls the keyboard (and serial) directly, sleeping briefly between polls.

Producers wake blocked consumers through the scheduler's input wait queues.