PERFORCE change 162927 for review

[Hans Petter Selasky]

http://perforce.freebsd.org/chv.cgi?CH=162927

Change 162927 by hselasky at hselasky_laptop001 on 2009/05/28 07:49:35

	
	LibUSB: Add more manpage details around "libusb20_tr_open".

Affected files ...

.. //depot/projects/usb/src/lib/libusb/libusb.3#10 edit

Differences ...

==== //depot/projects/usb/src/lib/libusb/libusb.3#10 (text+ko) ====

@@ -26,7 +26,7 @@
 .\"
 .\" $FreeBSD: src/lib/libusb/libusb.3,v 1.2 2009/04/05 18:30:24 thompsa Exp $
 .\"
-.Dd April 5, 2009
+.Dd May 28, 2009
 .Dt LIBUSB 3
 .Os
 .Sh NAME
@@ -231,7 +231,7 @@
 .Pp
 .
 .Fn libusb20_tr_open
-will allocate kernel resources like
+will allocate kernel buffer resources according to
 .Fa max_buf_size
 and
 .Fa max_frame_count
@@ -239,6 +239,18 @@
 .Fa pxfer
 and bind the transfer to the specified
 .Fa ep_no .
+.Fa max_buf_size
+is the minimum buffer size which the data transport layer has to support.
+If
+.Fa max_buf_size
+is zero, the
+.Nm
+library will use wMaxPacketSize to compute the buffer size.
+This can be useful for isochronous transfers.
+The actual buffer size can be greater than
+.Fa max_buf_size
+and is returned by
+.Fn libusb20_tr_get_max_total_length .
 .
 This function returns zero upon success.
 .