[src/uebayasi-xip]: src/share/man/man4 Minor wording improvement.

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

details:   https://anonhg.NetBSD.org/src/rev/c5b636c6b845
branches:  uebayasi-xip
changeset: 751613:c5b636c6b845
user:      snj <snj%NetBSD.org@localhost>
date:      Sat Feb 27 20:39:43 2010 +0000

description:
Minor wording improvement.

diffstat:

 share/man/man4/acpiec.4 |  123 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 123 insertions(+), 0 deletions(-)

diffs (127 lines):

diff -r d746210ee909 -r c5b636c6b845 share/man/man4/acpiec.4
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/share/man/man4/acpiec.4   Sat Feb 27 20:39:43 2010 +0000
@@ -0,0 +1,123 @@
+.\" $NetBSD: acpiec.4,v 1.6.2.2 2010/02/27 20:39:43 snj Exp $
+.\"
+.\" Copyright (c) 2002, 2004, 2010 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd February 27, 2010
+.Dt ACPIEC 4
+.Os
+.Sh NAME
+.Nm acpiec
+.Nd ACPI Embedded Controller
+.Sh SYNOPSIS
+.Cd "acpiec* at acpi?"
+.Cd "acpiecdt* at acpi?"
+.Sh DESCRIPTION
+The
+.Nm
+driver supports ACPI Embedded Controllers.
+.Pp
+An ACPI Embedded Controller
+.Pq Tn EC
+is typically a small microprocessor that is responsible for various tasks
+related to
+.Tn ACPI .
+The primary task is to handle
+.Tn ACPI
+specific interrupts, which are mapped to so-called
+.Tn ACPI
+General Purpose Events
+.Pq Tn GPEs .
+Other possible functions include embedded access to other buses such as the
+.Xr iic 4 .
+.Pp
+The
+.Tn ACPI
+specific events range from user initiated events to events triggered by
+the hardware.
+When such an event occurs, typically either a System Management Interrupt
+.Pq Tn SMI
+or a System Control Interrupt
+.Pq Tn SCI
+is raised.
+The latter is an active, visible, shareable, level interrupt.
+On most Intel chipsets
+.Tn SCI
+is hardwired to the interrupt number 9.
+The main task of an
+.Tn EC
+is to raise a system control interrupt.
+.Pp
+All GPEs generate SCIs.
+A typical example of the internal wiring of
+.Tn GPEs
+could involve
+.Xr gpio 4 :
+when, e.g., the
+.Tn AC
+adapter is connected, a certain
+.Tn GPIO
+line becomes active, a given
+.Tn GPE
+is flagged, and a
+.Tn SCI
+interrupt is raised by the
+.Tn EC ,
+leading to execution of
+.Tn ACPI
+machine code in order to locate the handler associated with the event.
+A corresponding driver,
+.Xr acpiacad 4
+in this case, will finally finish the processing of the event.
+.Pp
+Due to the reasons described above, majority of
+.Tn ACPI
+specific drivers are dysfunctional without
+.Nm .
+It is therefore recommended that
+.Nm
+is always enabled,
+even though it may not be required on some older systems.
+.Sh SEE ALSO
+.Xr acpi 4
+.Sh HISTORY
+The
+.Nm
+driver
+appeared in
+.Nx 1.6 .
+.Sh CAVEATS
+Many machines depend on early attachment of
+.Nm .
+In such cases the information required by
+.Nm
+should be available as a separate and optional
+Embedded Controller Descriptor Table
+.Pq Tn ECDT .
+If an
+.Tn ECDT
+is not available or early attachment can not be carried out due other reasons,
+the initialization of the whole
+.Xr acpi 4
+subsystem may be problematic.