svn commit: r365403 - head/share/man/man4
Li-Wen Hsu
lwhsu at FreeBSD.org
Mon Sep 7 07:44:15 UTC 2020
Author: lwhsu
Date: Mon Sep 7 07:44:14 2020
New Revision: 365403
URL: https://svnweb.freebsd.org/changeset/base/365403
Log:
Slightly improve usb(4)
- Mention USB 3.0
- Update links
- Fix `mandoc -T lint` warnings
Reviewed by: bcr, hselasky
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D26349
Modified:
head/share/man/man4/usb.4
Modified: head/share/man/man4/usb.4
==============================================================================
--- head/share/man/man4/usb.4 Mon Sep 7 06:53:29 2020 (r365402)
+++ head/share/man/man4/usb.4 Mon Sep 7 07:44:14 2020 (r365403)
@@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd April 24, 2018
+.Dd September 7, 2020
.Dt USB 4
.Os
.Sh NAME
@@ -52,8 +52,7 @@ for more information.
.Sh DESCRIPTION
.Fx
provides machine-independent bus support and drivers for
-.Tn USB
-devices in host and device side mode.
+USB devices in host and device side mode.
.Pp
The
.Nm
@@ -67,32 +66,25 @@ driver has three layers:
The controller attaches to a physical bus
like
.Xr pci 4 .
-The
-.Tn USB
-bus attaches to the controller, and the root hub attaches
+The USB bus attaches to the controller, and the root hub attaches
to the controller.
Any devices attached to the bus will attach to the root hub
-or another hub attached to the
-.Tn USB
-bus.
+or another hub attached to the USB bus.
.Pp
The
.Nm uhub
device will always be present as it is needed for the root hub.
.Sh INTRODUCTION TO USB
-The
-.Tn USB
-is a system where external devices can be connected to a PC.
+The USB is a system where external devices can be connected to a PC.
The most common USB speeds are:
.Bl -tag -width 6n -offset indent
-.It Low Speed (1.5MBit/sec)
-.It Full Speed (12MBit/sec)
-.It High Speed (480MBit/sec)
+.It Low Speed (1.5 MBit/sec)
+.It Full Speed (12 MBit/sec)
+.It High Speed (480 MBit/sec)
+.It SuperSpeed (5 GBit/sec)
.El
.Pp
-Each
-.Tn USB
-has a USB controller that is the master of the bus.
+Each USB has a USB controller that is the master of the bus.
The physical communication is simplex which means the host controller only
communicates with one USB device at a time.
.Pp
@@ -122,9 +114,7 @@ A device may operate in different configurations.
Depending on the configuration, the device may present different sets of
endpoints and interfaces.
.Pp
-The bus enumeration of the
-.Tn USB
-bus proceeds in several steps:
+The bus enumeration of the USB bus proceeds in several steps:
.Bl -enum
.It
Any interface specific driver can attach to the device.
@@ -144,11 +134,9 @@ debug message verbosity.
Default is 0.
.El
.Sh SEE ALSO
-The
-.Tn USB
-specifications can be found at:
+The USB specifications can be found at:
.Pp
-.D1 Pa http://www.usb.org/developers/docs/
+.D1 Pa https://www.usb.org/documents
.Pp
.Xr libusb 3 ,
.Xr aue 4 ,
@@ -178,7 +166,7 @@ specifications can be found at:
.Sh STANDARDS
The
.Nm
-module complies with the USB 2.0 standard.
+module complies with the USB 3.0 standard.
.Sh HISTORY
The
.Nm
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