[src/trunk]: src/sys/dev/usb Tune ugen(4) isochronous parameters to better su...

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

details:   https://anonhg.NetBSD.org/src/rev/6b8a796f79b8
branches:  trunk
changeset: 756659:6b8a796f79b8
user:      jakllsch <jakllsch%NetBSD.org@localhost>
date:      Tue Jul 27 20:20:46 2010 +0000

description:
Tune ugen(4) isochronous parameters to better support high speed pipes.

Fixes PR#43159.

Justification:

UGEN_NISORFRMS, previously 4, is now 8 because that's the number of
microframes per frame on a high speed bus.  This allows data to be
transfered every microframe if necessary.

UGEN_NISOREQS, previously 6, is now 4.  This is harder to justify,
but I didn't think the total number of buffer frames needed to be
much more than it was.

UGEN_NISOFRAMES, previously 500, is now (UGEN_NISORFRMS * UGEN_NISOREQS)
(32 with values as above).  This is all the more we've actually used.

diffstat:

 sys/dev/usb/ugen.c |  10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diffs (31 lines):

diff -r 2988851ebaac -r 6b8a796f79b8 sys/dev/usb/ugen.c
--- a/sys/dev/usb/ugen.c        Tue Jul 27 19:44:16 2010 +0000
+++ b/sys/dev/usb/ugen.c        Tue Jul 27 20:20:46 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ugen.c,v 1.109 2010/02/19 12:40:47 pooka Exp $ */
+/*     $NetBSD: ugen.c,v 1.110 2010/07/27 20:20:46 jakllsch Exp $      */
 
 /*
  * Copyright (c) 1998, 2004 The NetBSD Foundation, Inc.
@@ -37,7 +37,7 @@
 
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ugen.c,v 1.109 2010/02/19 12:40:47 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ugen.c,v 1.110 2010/07/27 20:20:46 jakllsch Exp $");
 
 #include "opt_compat_netbsd.h"
 
@@ -81,9 +81,9 @@
 #define        UGEN_IBSIZE     1020    /* buffer size */
 #define        UGEN_BBSIZE     1024
 
-#define        UGEN_NISOFRAMES 500     /* 0.5 seconds worth */
-#define UGEN_NISOREQS  6       /* number of outstanding xfer requests */
-#define UGEN_NISORFRMS 4       /* number of frames (miliseconds) per req */
+#define UGEN_NISOREQS  4       /* number of outstanding xfer requests */
+#define UGEN_NISORFRMS 8       /* number of transactions per req */
+#define UGEN_NISOFRAMES        (UGEN_NISORFRMS * UGEN_NISOREQS)
 
 #define UGEN_BULK_RA_WB_BUFSIZE        16384           /* default buffer size */
 #define UGEN_BULK_RA_WB_BUFMAX (1 << 20)       /* maximum allowed buffer */