v0.5.10: USB HID mouse via polled xHCI (rsnix/src/usb.rs)

Polled xHCI driver (mouse-only): controller bring-up, port reset,
enable-slot -> address-device -> config-descriptor walk -> HID boot
mouse IN endpoint, one outstanding IN TRB drained on poll.  Cursor
task polls usb first, PS/2 second.  New 'usb'/'usb rescan' shell cmds.

Verified in QEMU (q35 + OVMF + qemu-xhci + usb-mouse): movement and
all three buttons tracked exactly; heap stays clean.

Fixes en route: MaxPorts=HCSPARAMS1[31:24]; operational regs CRCR=0x18
DCBAAP=0x30 CONFIG=0x38; pass input-context ptr in Address-Device;
Input Control Context DW0=Drop DW1=Add; HID walker bInterfaceClass at
+5; async discovery from cursor task.

1 files changed, 1 insertions, 1 deletions

diff --git a/rsnix/src/cursor.rs b/rsnix/src/cursor.rs
index 18c9a1d..d9d97bc 100644
--- a/rsnix/src/cursor.rs
+++ b/rsnix/src/cursor.rs
@@ -50,7 +50,7 @@ fn forward_target() -> Option<usize> {
 
 fn task_main() {
     loop {
-        while let Some(ev) = crate::ps2::try_poll_mouse() {
+        while let Some(ev) = crate::usb::poll_mouse().or_else(crate::ps2::try_poll_mouse) {
             crate::gop::cursor_move(ev.dx, ev.dy);
             crate::gop::cursor_set_buttons(btn_bits(&ev));
             if let Some(id) = forward_target()