[src/trunk]: src/share/man/man9 add doucmentation for usb_{add, rem, init}_task().

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

details:   https://anonhg.NetBSD.org/src/rev/293ba3196045
branches:  trunk
changeset: 779563:293ba3196045
user:      mrg <mrg%NetBSD.org@localhost>
date:      Sun Jun 03 02:56:36 2012 +0000

description:
add doucmentation for usb_{add,rem,init}_task().

diffstat:

 share/man/man9/usbdi.9 |  33 +++++++++++++++++++++++++++------
 1 files changed, 27 insertions(+), 6 deletions(-)

diffs (54 lines):

diff -r 185dd6657837 -r 293ba3196045 share/man/man9/usbdi.9
--- a/share/man/man9/usbdi.9    Sun Jun 03 02:23:37 2012 +0000
+++ b/share/man/man9/usbdi.9    Sun Jun 03 02:56:36 2012 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: usbdi.9,v 1.20 2012/06/03 02:23:37 mrg Exp $
+.\"    $NetBSD: usbdi.9,v 1.21 2012/06/03 02:56:36 mrg Exp $
 .\"
 .\" Copyright (c) 2012 Matthew R. Green
 .\" All rights reserved.
@@ -417,11 +417,6 @@
 .\"
 .\" .Fn usb_desc_iter_init "usbd_device_handle iface" "usbd_desc_iter_t *iter"
 .\" .Fn usb_desc_iter_next "usbd_desc_iter_t *iter"
-.\" .Fn usb_add_task "usbd_device_handle iface" "struct usb_task *task" \
-.\"  "int queue"
-.\" .Fn usb_rem_task "usbd_device_handle iface" "struct usb_task *task"
-.\" .Fn usb_init_task "struct usb_task *task" "void (*func)(void *)" \
-.\"  "void *arg"
 .\"
 .\" XXX functions missing descriptions in usbdi.h XXX
 .\"
@@ -920,6 +915,32 @@
 function works like
 .Fn usb_detach_broadcast .
 .\" XXX add an actual code example.
+.Sh USB TASK MANAGEMENT
+The USB stack provides a task management framework to execute tasks
+in a thread context at the soonest opportunity.
+Typically this is used by network drivers to handle periodic updates
+or status change requests.
+The
+.Fn usb_init_task
+function takes a pointer to a
+.Ft struct usb_task
+that will be initalised, a function to call for this task
+.Fa func ,
+and the argument to pass to
+.Fa func ,
+.Fa arg .
+To schedule the task to be run the
+.Fn usb_add_task
+function should be called with the
+.Fa iface
+associated with this device, the task queue to invoke
+.Fa task ,
+and the
+.Fa queue
+to run against, either
+.Dv USB_TASKQ_HC
+or
+.Dv USB_TASKQ_DRIVER .
 .Sh SEE ALSO
 .Xr usb 4 ,
 .Xr usbd_status 9