From a01d3ce6e5248ee612d73ae7dffb0627a51fa410 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Mon, 13 Jul 2026 20:23:20 +0200
Subject: [PATCH] Fix a race condition when receiving events before unmasking
 interrupts

---
 drivers/usb/xhcid/src/xhci/irq_reactor.rs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/usb/xhcid/src/xhci/irq_reactor.rs b/drivers/usb/xhcid/src/xhci/irq_reactor.rs
index efe8f74610..1b27479527 100644
--- a/drivers/usb/xhcid/src/xhci/irq_reactor.rs
+++ b/drivers/usb/xhcid/src/xhci/irq_reactor.rs
@@ -240,9 +240,20 @@ impl<const N: usize> IrqReactor<N> {
                             warn!("xhci: Received interrupt, but no event was found in the event ring. Ignoring interrupt.")
                         }
                         self.unmask_interrupts();
+
+                        // Process any events received between the NoEvent and unmasking interrupts
+                        loop {
+                            match self.process_one_event(&mut event_ring, &mut event_trb_index) {
+                                EventProcessResult::NoEvent => break,
+                                EventProcessResult::EventRingFull
+                                | EventProcessResult::RegularEvent => {}
+                            }
+                        }
+
                         continue 'trb_loop;
                     }
                     EventProcessResult::EventRingFull => {
+                        // FIXME can this use the RegularEvent path?
                         if self.hci.interrupt_is_pending(0) {
                             warn!("After incrementing the dequeue pointer, the interrupt bit is still pending.")
                         } else {