[src/trunk]: src/sys/dev/usb Fix a done list handling bug which exhibits unde...

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

details:   https://anonhg.NetBSD.org/src/rev/fab76a773d09
branches:  trunk
changeset: 553163:fab76a773d09
user:      toshii <toshii%NetBSD.org@localhost>
date:      Sat Oct 11 03:04:26 2003 +0000

description:
Fix a done list handling bug which exhibits under high shared interrupt
rate and bus traffic.  As the interrupt register is read after checking
hcca_done_head, there was a small chance of dropping a done list.
Ignore OHCI_WDH interrupt bit if hcca_done_head is zero so that OHCI_WDH
is processed later.

diffstat:

 sys/dev/usb/ohci.c |  6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diffs (27 lines):

diff -r 548f4dcfaf06 -r fab76a773d09 sys/dev/usb/ohci.c
--- a/sys/dev/usb/ohci.c        Sat Oct 11 03:01:53 2003 +0000
+++ b/sys/dev/usb/ohci.c        Sat Oct 11 03:04:26 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ohci.c,v 1.141 2003/09/10 20:08:29 mycroft Exp $       */
+/*     $NetBSD: ohci.c,v 1.142 2003/10/11 03:04:26 toshii Exp $        */
 /*     $FreeBSD: src/sys/dev/usb/ohci.c,v 1.22 1999/11/17 22:33:40 n_hibma Exp $       */
 
 /*
@@ -46,7 +46,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ohci.c,v 1.141 2003/09/10 20:08:29 mycroft Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ohci.c,v 1.142 2003/10/11 03:04:26 toshii Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1121,7 +1121,7 @@
                        intrs |= OREAD4(sc, OHCI_INTERRUPT_STATUS);
                sc->sc_hcca->hcca_done_head = 0;
        } else
-               intrs = OREAD4(sc, OHCI_INTERRUPT_STATUS);
+               intrs = OREAD4(sc, OHCI_INTERRUPT_STATUS) & ~OHCI_WDH;
 
        if (!intrs)
                return (0);