[src/nick-nhusb]: src/sys/dev/usb Add a comment

[skrll <skrll%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/42ee6c4a3816
branches:  nick-nhusb
changeset: 334407:42ee6c4a3816
user:      skrll <skrll%NetBSD.org@localhost>
date:      Fri Feb 19 16:23:15 2016 +0000

description:
Add a comment

diffstat:

 sys/dev/usb/ehci.c |  9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diffs (30 lines):

diff -r 2d950fa8a709 -r 42ee6c4a3816 sys/dev/usb/ehci.c
--- a/sys/dev/usb/ehci.c        Fri Feb 19 08:22:40 2016 +0000
+++ b/sys/dev/usb/ehci.c        Fri Feb 19 16:23:15 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ehci.c,v 1.234.2.86 2016/02/07 13:58:19 skrll Exp $ */
+/*     $NetBSD: ehci.c,v 1.234.2.87 2016/02/19 16:23:15 skrll Exp $ */
 
 /*
  * Copyright (c) 2004-2012 The NetBSD Foundation, Inc.
@@ -53,7 +53,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ehci.c,v 1.234.2.86 2016/02/07 13:58:19 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ehci.c,v 1.234.2.87 2016/02/19 16:23:15 skrll Exp $");
 
 #include "ohci.h"
 #include "uhci.h"
@@ -832,6 +832,11 @@
 
        }
 
+       /*
+        * We abuse ex_next for the interrupt and complete lists and
+        * interrupt transfers will get re-added here so use
+        * the _SAFE version of TAILQ_FOREACH.
+        */
        TAILQ_FOREACH_SAFE(ex, &cq, ex_next, nextex) {
                /*
                 * XXX transfer_complete memcpys out transfer data (for in