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Flesh out the section on device hints a bit more and add explicit text

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on adding hints from the boot loader.

Reviewed by:	trhodes
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Scott Long 2002-12-07 15:34:23 +00:00
parent 70603a0e48
commit 13b5a755ec
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=15211
1 changed files with 24 additions and 13 deletions
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37
en_US.ISO8859-1/books/handbook/boot/chapter.sgml
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@ -582,27 +582,38 @@ boot:</screen>
</indexterm>
<title>Device Hints</title>
<note><para>This is a FreeBSD&nbsp;5.0 and later feature which does not
exist in earlier versions.</para></note>
<para>During initial system startup, the boot &man.loader.8; will read the
&man.device.hints.5; file. This file stores kernel boot information
known as variables, sometimes referred to as <quote>device hints</quote>.</para>
known as variables, sometimes referred to as <quote>device hints</quote>.
These <quote>device hints</quote> are used by device drivers for device
configuration.</para>
<note><para>This is a FreeBSD&nbsp;5.0 and later feature which does not exist in earlier
versions.</para></note>
<para>Device hints may also be specified at the <link linkend="boot-loader">
Stage 3 boot loader</link> prompt. Variables can be added using
<command>set</command>, removed with <command>unset</command>, and viewed
with the <command>show</command> commands. Variables set in the
device.hints file can be overridden here also. Device hints entered at
the boot loader are not permanent and will be forgotten on the next
reboot.</para>
<para>Setup of this file is one variable per line, using the standard hash
<quote>#</quote> as comment markers. After system initialization, new
variables can be added using <command>set</command>, removed with
<command>unset</command>, and viewed with the <command>show</command>
commands. Using the &man.kenv.1; command, you can dump all of these
variables.</para>
<para>Once the system is booted, the &man.kenv.1; command can be used to
dump all of the variables.</para>
<para>These <quote>device hints</quote> are used by device drivers for device
control. Syntax works as follows:</para>
<para>The syntax for the device.hints file is one variable per line, using
the standard hash <quote>#</quote> as comment markers. Lines are
constructed as follows:</para>
<screen><userinput>hint.driver.unit.keyword="value"</userinput></screen>
<para>where driver is the device driver, unit is the unit number and keyword
is the hint keyword. The keyword may consist of the following options:</para>
<para>The syntax for the Stage 3 boot loader is:</para>
<screen><userinput>set hint.driver.unit.keyword=value</userinput></screen>
<para><quote>driver</quote> is the device driver name, <quote>unit</quote>
is the device driver unit number, and <quote>keyword</quote> is the hint
keyword. The keyword may consist of the following options:</para>
<itemizedlist>
<listitem>