lfs-book/chapter06/hotplug.xml

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  <!ENTITY % general-entities SYSTEM "../general.ent">
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<sect1 id="ch-system-hotplug" role="wrap">
<title>Hotplug-&hotplug-version;</title>
<?dbhtml filename="hotplug.html"?>

<indexterm zone="ch-system-hotplug"><primary sortas="a-Hotplug">Hotplug</primary></indexterm>

<sect2 role="package"><title/>

<para>The Hotplug package contains scripts that react upon various changes
in the kernel state, in particular, addition and removal of hardware. This
package also detects existing hardware during boot and inserts the relevant
modules into the running kernel.
</para>
<segmentedlist>
<segtitle>&buildtime;</segtitle>
<segtitle>&diskspace;</segtitle>
<seglistitem><seg>0.01 SBU</seg><seg>0.1 MB</seg></seglistitem>
</segmentedlist>

</sect2>

<sect2 role="installation">
<title>Installation of Hotplug</title>

<para>
By default, Hotplug does not output anything in its initscript and places it
into
<filename class="directory">/etc/init.d</filename>,
whereas the place for initscripts in LFS is
<filename class="directory">/etc/rc.d/init.d</filename>. Apply the patch
that makes the output of hotplug initscript more verbose and places this
initscript into the proper directory:
</para>

<screen><userinput>patch -Np1 -i ../hotplug-&hotplug-version;-cosmetic-2.patch
</userinput></screen>

<para>
Apply the patch that avoids bogus dependencies of the hotplug initscript
upon <application>which</application> and
<application>usbutils</application> packages:
</para>

<screen><userinput>patch -Np1 -i ../hotplug-&hotplug-version;-bogus-deps-1.patch
</userinput></screen>

<para>
USB coldplugging is somewhat broken in Hotplug by default. Fix this with the
following patch:
</para>

<screen><userinput>patch -Np1 -i ../hotplug-&hotplug-version;-device-2.patch
</userinput></screen>

<para>
At last, there is an optional patch that adds ISAPNP hardware detection
capabilities to hotplug. It is not well tested. If you chose to apply it,
run the following command:
</para>

<screen><userinput>patch -Np1 -i ../hotplug-&hotplug-version;-isapnp-2.patch
</userinput></screen>


<para>And finally install the hotplug package:</para>

<screen><userinput>make install</userinput></screen>

<para>Make a symbolic link that tells the lfs-bootscripts package to run the
hotplug initscript after mounting and cleaning filesystems:</para>

<screen><userinput>ln -sf ../init.d/hotplug /etc/rc.d/init.d/S55hotplug</userinput></screen>

<para>
If you have applied the ISAPNP patch, add some required entries to
<filename>/etc/modprobe.conf</filename>:</para>

<screen><userinput>cat &gt;&gt;/etc/modprobe.conf &lt;&lt;"EOF"</userinput>
# Begin /etc/modprobe.conf entries for ISAPNP hardware detection script
# by Marco d'Itri
alias pnp:dPNP0511 irtty-sir
alias pnp:dPNP0700 floppy
alias pnp:dPNP0800 pcspkr
alias pnp:dPNP0B00 rtc
alias pnp:dPNP0303 atkbd
alias pnp:dPNP0F13 psmouse
alias pnp:dPNPB02F analog
# End /etc/modprobe.conf entries for ISAPNP hardware detection script
<userinput>EOF</userinput></screen>

<para>These entries may become unneded for newer versions of Linux kernel,
since Marco d'Itri will try to convince developers to put them into the
corresponding modules themselves.</para>

</sect2>


<sect2 id="contents-hotplug" role="content"><title>Contents of Hotplug</title>
<para></para>
</sect2>

<variablelist>
<varlistentry>
<term id="hotplug"><command>/sbin/hotplug</command></term>
<listitem>
<indexterm zone="ch-system-hotplug hotplug"><primary
sortas="b-hotplug">hotplug</primary></indexterm>
<para>This script is called by default by Linux kernel when something
changes in its internal state (e.g. a new device is added or removed).</para>
</listitem>
</varlistentry>

<varlistentry>
<term id="hotplug-initscript"><command>hotplug</command> initscript</term>
<listitem>
<indexterm zone="ch-system-hotplug hotplug-initscript"><primary
sortas="d-hotplug-initscript">hotplug</primary></indexterm>
<para>This script just runs all
<filename>/etc/hotplug/*.rc</filename> scripts in turn during system
startup.</para>
</listitem>
</varlistentry>

<varlistentry>
<term id="hotplug-rc"><command>*.rc</command> files in
<filename class="directory">/etc/hotplug</filename> directory</term>
<listitem>
<para>These scripts are used for cold plugging, i.e. detection and other
specific actions upon hardware already present during system startup. These
scripts try to find kernel modules corresponding to your hardware and insert
them into the running kernel.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term id="hotplug-agent"><command>*.agent</command> files in
<filename class="directory">/etc/hotplug</filename> directory</term>
<listitem>
<para>These scripts are called by <command>/sbin/hotplug</command>
in response to different types of hotplug events generated by the kernel.
Their action is to insert corresponding kernel modules and call user-provided
scripts, if any.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term id="hotplug-functions"><filename>/etc/hotplug/hotplug.functions</filename></term>
<listitem>
<para>This file contains common functions used by other scripts in hotplug
package.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term id="hotplug-blacklist"><filename>/etc/hotplug/blacklist</filename></term>
<listitem>
<indexterm zone="ch-system-hotplug hotplug-blacklist"><primary
sortas="e-/etc/hotplug/blacklist">/etc/hotplug/blacklist</primary></indexterm>
<para>This file contains the list of modules that should never be
inserted into the kernel by hotplug scripts.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term id="hotplug-subdirs"><filename class="directory">/etc/hotplug/{pci,usb}</filename></term>
<listitem>
<para>These directories are supposed to contain user-written handlers for
hotplug events.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term id="hotplug-usb.usermap"><filename>/etc/hotplug/usb.usermap</filename></term>
<listitem>
<indexterm zone="ch-system-hotplug hotplug-usb.usermap"><primary
sortas="e-/etc/hotplug/usb.usermap">/etc/hotplug/usb.usermap</primary></indexterm>
<para>This file contains rules that determine which user-defined handlers to
call for each USB device, based on its vendor, id and other attributes.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term id="hotplug-hotplug.d"><filename class="directory">/etc/hotplug.d</filename></term>
<listitem>
<para>This directory contains programs (or symlinks to them)
that are interested in receiving all hotplug events. E.g.,
<application>udev</application> puts its symlink here during installation.
</para>
</listitem>
</varlistentry>
</variablelist>
</sect1>