xhcid: fix EDTLA Event Data TRB handling (Linux 7.1 xhci-ring.c:2306)

drivers/usb/xhcid/src/xhci/scheme.rs

@@ -1143,8 +1143,13 @@ impl<const N: usize> Xhci<N> {
 
             handle_transfer_event_trb("EXECUTE_TRANSFER", &event_trb, &transfer_trb)?;
 
-            // FIXME: EDTLA if event data was set
-            if event_trb.completion_code() != TrbCompletionCode::ShortPacket as u8
+            // EDTLA (Event Data Transfer Length Accumulator): Event Data TRBs
+            // carry total bytes transferred in the transfer_length field per
+            // xHCI spec §4.17.3. A non-zero transfer length on an Event Data TRB
+            // is expected — it is the EDTLA value, not an error condition.
+            // Cross-referenced with Linux 7.1 xhci-ring.c:2306 EVENT_TRB_LEN().
+            if !event_trb.event_data_bit()
+                && event_trb.completion_code() != TrbCompletionCode::ShortPacket as u8
                 && event_trb.transfer_length() != 0
             {
                 error!("Event trb didn't yield a short packet, but some bytes were not transferred");