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usb: poll root ports on the tick — catch a late USB2 connection (edge-triggered) 

Real-hardware root-cause: the user's keyboard works in the firmware boot
menu but dies under danos. The port dump shows why — danos scans the
root ports ~3 ms after the controller reset, but a USB2 connection needs
~100 ms to debounce, so the boot scan sees the USB2 companion hub's port
empty (all USB2 ports ccs=0), while the SuperSpeed devices (hub, storage)
train instantly and DO show up. danos then relied on a Port Status
Change EVENT to catch the late USB2 connection, which does not fire
reliably on this hardware.

The tick now polls every root port and reconciles on the empty->connected
EDGE (previous-state tracked per port, seeded from the boot scan so
already-up ports never re-fire), bringing up a device that appears after
the scan without depending on the event. Edge-triggered so a port that
fails to enumerate is not retried every 8 ms. Branch-only until the
keyboard is confirmed on real hardware; the diagnostic dumps stay for
the next boot.
This commit is contained in:
Daniel Samson 2026-07-21 23:06:49 +01:00
parent 10956c6660
commit 0b10a637ae
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1 changed files with 28 additions and 0 deletions
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28
system/drivers/usb-xhci-bus/usb-xhci-bus.zig
View File

@ -189,6 +189,10 @@ fn speedName(speed: u32) []const u8 {
/// class driver against.
var manager_handle: ?runtime.ipc.Handle = null;
// Per-root-port connected state from the previous tick, so the poll acts on
// empty->connected transitions (edge), never re-attempting a level every tick.
var prev_connected: [64]bool = [_]bool{false} ** 64;
fn scanPorts(manager: runtime.ipc.Handle) void {
const engine = if (controller) |*c| c else {
_ = runtime.system.write("/system/drivers/usb-xhci-bus: controller not initialised\n");
@ -204,6 +208,7 @@ fn scanPorts(manager: runtime.ipc.Handle) void {
var connected: u32 = 0;
while (port <= engine.max_ports) : (port += 1) {
if (!engine.portConnected(port)) continue;
if (port < prev_connected.len) prev_connected[port] = true; // don't re-fire the poll for these
connected += 1;
bringUpPort(manager, engine, port);
}
@ -495,6 +500,29 @@ fn onNotification(badge: u64) void {
if (badge & runtime.ipc.notify_timer_bit == 0) return;
if (controller) |*engine| {
engine.pump();
// Poll every root port and reconcile — a device present but not yet
// enumerated is brought up; a device gone is torn down. This does NOT
// depend on a Port Status Change EVENT firing: the boot scan runs ~3 ms
// after the controller reset, far too early for a USB2 connection to
// debounce (~100 ms), and the SuperSpeed devices that DO show up early
// proved the event path unreliable for the late USB2 companion hub on
// real hardware. Polling catches it on the next tick regardless.
if (manager_handle) |manager| {
var port: u32 = 1;
while (port <= engine.max_ports and port <= prev_connected.len) : (port += 1) {
const connected = engine.portConnected(port);
const was = prev_connected[port];
prev_connected[port] = connected;
if (connected and !was and engine.deviceOnPort(port) == null) {
// Rising edge the boot scan missed (it ran before the USB2
// connection debounced): bring the device up now.
std.log.info("root port {d}: device appeared (PORTSC 0x{x:0>8})", .{ port, engine.portStatus(port) });
bringUpPort(manager, engine, port);
} else if (!connected and was and engine.deviceOnPort(port) != null) {
tearDownPort(manager, engine, port);
}
}
}
while (engine.takePortChange()) |port| {
const manager = manager_handle orelse break;
const connected = engine.portConnected(port);