boards/BRINGUP.md A3 and S3, FABRIC-3 SXLI. A HID boot keyboard is
configured (interrupt IN endpoint, SET_PROTOCOL boot) and its reports
become the same Linux-keycode events as PS/2 and virtio (usb_kbd.c): the
full layout -- F-keys, navigation block, arrows, Num Lock, keypad. The
console treats Caps and Num Lock as toggles shown on the keyboard's
lights, and the keypad as digits or navigation. While a USB keyboard
runs, its event ring is serviced every tick, not once a second.
Found on the way: with no i8042 (port 0x64 reads 0xFF) the kernel hung at
boot in an endless drain -- a legacy-free PC would stop there. Detected
and skipped now; drains bounded.
QEMU, amd64 with the USB keyboard the only one: 1 2 + . on main keys and
keypad, Caps Lock, Num Lock all right; aarch64/riscv64 configure it too.
Acceptance on three ISAs unchanged; identities hot-plug.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
