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, 4 insertions, 2 deletions

diff --git a/rsdos/src/main.rs b/rsdos/src/main.rs
index e40098d..27dab06 100644
--- a/rsdos/src/main.rs
+++ b/rsdos/src/main.rs
@@ -185,7 +185,7 @@ pub unsafe extern "efiapi" fn efi_main(image_handle: Handle, system_table: *mut
     } else {
         rsnix::serial_println!("gop: not found (0x{:x})", gop_result);
     }
-    rsnix::gop::boot_marker("rsnix v0.5.9 booting..");
+    rsnix::gop::boot_marker("rsnix v0.5.10 booting..");
     rsnix::vt::init();
     let (rows, cols) = rsnix::vt::size();
     rsnix::serial_println!("vt: terminal ready ({}x{})", rows, cols);
@@ -347,7 +347,9 @@ pub unsafe extern "efiapi" fn efi_main(image_handle: Handle, system_table: *mut
 
     rsnix::serial_println!("boot: entering shell");
     rsnix::gop::boot_marker("rsnix: boot done — shell");
-    if rsnix::ps2::mouse_present() {
+    // USB (xHCI) mouse is polled; fall back to PS/2 if no USB mouse.
+    rsnix::usb::init();
+    if rsnix::ps2::mouse_present() || rsnix::usb::controller_up() {
         rsnix::cursor::spawn();
     } else {
         rsnix::serial_println!("cursor: no mouse — overlay disabled");