[src/trunk]: src/share/man/man4 Explain wedge auto discovery.

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

details:   https://anonhg.NetBSD.org/src/rev/480f744a81ab
branches:  trunk
changeset: 979682:480f744a81ab
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Tue Jan 05 22:17:40 2021 +0000

description:
Explain wedge auto discovery.

diffstat:

 share/man/man4/dk.4 |  38 ++++++++++++++++++++++++++++++++++++--
 1 files changed, 36 insertions(+), 2 deletions(-)

diffs (80 lines):

diff -r f717418754b4 -r 480f744a81ab share/man/man4/dk.4
--- a/share/man/man4/dk.4       Tue Jan 05 21:40:42 2021 +0000
+++ b/share/man/man4/dk.4       Tue Jan 05 22:17:40 2021 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: dk.4,v 1.7 2017/02/26 11:56:49 rin Exp $
+.\"    $NetBSD: dk.4,v 1.8 2021/01/05 22:17:40 mlelstv Exp $
 .\"
 .\" Copyright (c) 2006 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\" Jonathan A. Kollasch used vnd(4) as the template for this man page.
 .\"
-.Dd February 26, 2017
+.Dd October 26, 2020
 .Dt DK 4
 .Os
 .Sh NAME
@@ -43,6 +43,7 @@
 .Cd "options DKWEDGE_METHOD_GPT"
 .Cd "options DKWEDGE_METHOD_MBR"
 .Cd "options DKWEDGE_METHOD_RDB"
+.Cd "options DKWEDGE_METHOD_APPLE"
 .Sh DESCRIPTION
 The
 .Nm
@@ -52,20 +53,53 @@
 Wedges may be configured manually with
 .Xr dkctl 8
 or automatically by the kernel upon the attachment of the physical disk.
+
+Wedges needs to have a unique name. If a duplicate name is detected during
+autodiscovery, that partition is ignored.
 .Sh KERNEL OPTIONS
 .Bl -tag -width DKWEDGE_METHOD_BSDLABEL
 .It Dv DKWEDGE_AUTODISCOVER
 Automatically detect and configure wedges using any available methods.
+Currently only DKWEDGE_METHOD_GPT and DKWEDGE_METHOD_APPLE are enabled
+by default.
+
+For each partition found, a wedge with a corresponding name is created.
 .It Dv DKWEDGE_METHOD_BSDLABEL
 BSD disklabel detection method.
+
+For each configured partition in the
+.Xr disklabel 5
+that is not of type
+.Va FS_UNUSED,
+a wedge is created and named after the
+.Va d_packname
+field followed by "/" and the partition letter a..p.
+
+When the
+.Va d_packname
+is empty or has the value "fictitious" the regular partition names
+are used as wedge names, i.e. the device name, unit number and
+partition letter, for example "wd0a".
 .It Dv DKWEDGE_METHOD_GPT
 Extensible Firmware Interface Globally Unique Identifier Partition Table
 (GPT) detection method.
+
+For every GPT partition a wedge is created and named after the
+partition label.
+GPT partitions are UTF-16-encoded, this is converted into UTF-8.
+If a partition has no label, it's UUID is used instead.
 .It Dv DKWEDGE_METHOD_MBR
 IBM PC-compatible Master Boot Record (MBR) partitioning detection method,
 with support for Extended MBRs.
+
+For every partition in the MBR a wedge is created and named like a
+regular partition name, i.e. the device name, unit number and a
+parititon letter, for example "wd0e".
+Primary partitions start with "e", extended partitions start with "i".
 .It Dv DKWEDGE_METHOD_RDB
 Amiga Rigid Disk Block (RDB) partitioning detection method.
+.It Dv DKWEDGE_METHOD_APPLE
+Apple partition map detection method.
 .El
 .Sh FILES
 .Bl -tag -width /dev/XXrXdkX -compact