[src/trunk]: src/sys/dev/usb in alloc_sqtd_chain(), deal with the case where ...

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

details:   https://anonhg.NetBSD.org/src/rev/c72539214725
branches:  trunk
changeset: 764405:c72539214725
user:      drochner <drochner%NetBSD.org@localhost>
date:      Wed Apr 20 09:32:43 2011 +0000

description:
in alloc_sqtd_chain(), deal with the case where a data packet ends
exactly at a page boundary, and the FORCE_SHORT_XFER was set by the
client (which causes that an empty descriptor is needed to terminate
the transfer), from Gordon McNutt per PR kern/44883
(fixed a bit differently than the proposed patch for aesthetical
reasons -- avoids the page pointer to come into unexpexted area earlier)

diffstat:

 sys/dev/usb/ehci.c |  7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diffs (28 lines):

diff -r 71b05e21c7cb -r c72539214725 sys/dev/usb/ehci.c
--- a/sys/dev/usb/ehci.c        Wed Apr 20 08:36:07 2011 +0000
+++ b/sys/dev/usb/ehci.c        Wed Apr 20 09:32:43 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ehci.c,v 1.173 2011/01/18 15:05:03 jmcneill Exp $ */
+/*     $NetBSD: ehci.c,v 1.174 2011/04/20 09:32:43 drochner Exp $ */
 
 /*
  * Copyright (c) 2004-2008 The NetBSD Foundation, Inc.
@@ -52,7 +52,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ehci.c,v 1.173 2011/01/18 15:05:03 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ehci.c,v 1.174 2011/04/20 09:32:43 drochner Exp $");
 
 #include "ohci.h"
 #include "uhci.h"
@@ -2750,7 +2750,8 @@
                usb_syncmem(&cur->dma, cur->offs, sizeof(cur->qtd),
                    BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD);
                DPRINTFN(10,("ehci_alloc_sqtd_chain: extend chain\n"));
-               dataphys += curlen;
+               if (len)
+                       dataphys += curlen;
                cur = next;
        }
        cur->qtd.qtd_status |= htole32(EHCI_QTD_IOC);