Clarify the functionality of usbd a bit more.

1 files changed, 24 insertions, 3 deletions

diff --git a/usr.sbin/usbd/usbd.8 b/usr.sbin/usbd/usbd.8
index 0f3f5ef..c56a45b 100644
--- a/usr.sbin/usbd/usbd.8
+++ b/usr.sbin/usbd/usbd.8
@@ -42,15 +42,36 @@
 .Nd supervise USB attach/detach
 .Sh SYNOPSIS
 .Nm
+.Op Fl c Ar configfile
 .Op Fl d
+.Op Fl e
 .Op Fl f Ar device
+.Op Fl n
 .Op Fl t Ar timeout
 .Op Fl v
 .Sh DESCRIPTION
 .Nm
-handles the USB device attachment and detachment.
+handles the USB device attachment and detachment. It does two things.
+Through opening the
+.Pa /dev/usb0 ,
+.Pa /dev/usb1 ,
+etc. devices, it enables the kernel to do handle change requests from
+attached hubs. This functionality will be removed when the kernel has
+kernel threads. The (multiple)
+.Fl f Ar device
+command line options specify which controllers it should handle.
+Normally this option is not needed.
 .Pp
-The options are as follows:
+The second part is the handling of the attachment and detachment of USB
+devices. The device
+.Pa /dev/usb
+is opened and events are read from it. Whenever a device is attached or
+detached the list of actions read from
+.Pa /etc/usbd.conf
+are searched for a matching entry. If found, the corresponding action is
+executed.
+.Pp
+The command line options are as follows:
 .Bl -tag -width Ds
 .It Fl c Ar filename
 Name of configuration file. The default is
@@ -59,7 +80,7 @@ Name of configuration file. The default is
 Enable debugging to the standard output,
 and do not disassociate from the controlling terminal.
 .It Fl e
-Do one device tree exploration and then exit.
+Do one device tree exploration, no event queue handling and then exit.
 .It Fl f Ar device
 Specify the pathname of a USB controller device file.
 The flag may be repeated to watch more than one USB controller.