-<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
-<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+<?xml version='1.0'?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
-<refentry id="hwdb">
+<refentry id="hwdb" conditional="ENABLE_HWDB">
<refentryinfo>
<title>hwdb</title>
<productname>systemd</productname>
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Kay</firstname>
- <surname>Sievers</surname>
- <email>kay@vrfy.org</email>
- </author>
- <author>
- <contrib>Developer</contrib>
- <firstname>Tom</firstname>
- <surname>Gundersen</surname>
- <email>teg@jklm.no</email>
- </author>
- </authorgroup>
</refentryinfo>
<refmeta>
<refsect1><title>Description</title>
<para>The hardware database is a key-value store for associating modalias-like keys to
- udev-properties-like values. It is used primarily by udev to add the relevant properties
+ udev-property-like values. It is used primarily by udev to add the relevant properties
to matching devices, but it can also be queried directly.</para>
</refsect1>
<refsect1><title>Hardware Database Files</title>
<para>The hwdb files are read from the files located in the
- system hwdb directory <filename>/usr/lib/udev/hwdb.d</filename>,
- the volatile runtime directory <filename>/run/udev/hwdb.d</filename>
- and the local administration directory <filename>/etc/udev/hwdb.d</filename>.
+ system hwdb directory <filename>/usr/lib/udev/hwdb.d</filename> and
+ the local administration directory <filename>/etc/udev/hwdb.d</filename>.
All hwdb files are collectively sorted and processed in lexical order,
regardless of the directories in which they live. However, files with
identical filenames replace each other. Files in <filename>/etc</filename>
- have the highest priority, files in <filename>/run</filename> take precedence
- over files with the same name in <filename>/usr/lib</filename>. This can be
- used to override a system-supplied hwdb file with a local file if needed;
+ have the highest priority and take precedence over files with the same
+ name in <filename>/usr/lib</filename>. This can be used to override a
+ system-supplied hwdb file with a local file if needed;
a symlink in <filename>/etc</filename> with the same name as a hwdb file in
<filename>/usr/lib</filename>, pointing to <filename>/dev/null</filename>,
- disables the hwdb file entirely. hwdb files must have the extension
+ disables that hwdb file entirely. hwdb files must have the extension
<filename>.hwdb</filename>; other extensions are ignored.</para>
- <para>The hwdb file contains data records consisting of matches and
- associated key-value pairs. Every record in the hwdb starts with one or
- more match string, specifying a shell glob to compare the database
- lookup string against. Multiple match lines are specified in additional
- consecutive lines. Every match line is compared indivdually, they are
- combined by OR. Every match line must start at the first character of
- the line.</para>
+ <para>Each hwdb file contains data records consisting of matches and associated
+ key-value pairs. Every record in the hwdb starts with one or more match strings,
+ specifying a shell glob to compare the lookup string against. Multiple match lines
+ are specified in consecutive lines. Every match line is compared individually, and
+ they are combined by OR. Every match line must start at the first character of the
+ line.</para>
- <para>The match lines are followed by one or more key-value pair lines, which
- are recognized by a leading space character. The key name and value are separated
- by <literal>=</literal>. An empty line signifies the end
- of a record. Lines beginning with <literal>#</literal> are ignored.</para>
+ <para>The match lines are followed by one or more key-value pair lines, which are
+ recognized by a leading space character. The key name and value are separated by
+ <literal>=</literal>. An empty line signifies the end of a record. Lines beginning
+ with <literal>#</literal> are ignored.</para>
+
+ <para>In case multiple records match a given lookup string, the key-value pairs
+ from all records are combined. If a key is specified multiple times, the value
+ from the record with the highest priority is used (each key can have only a single
+ value). The priority is higher when the record is in a file that sorts later
+ lexicographically, and in case of records in the same file, later records have
+ higher priority.</para>
<para>The content of all hwdb files is read by
<citerefentry><refentrytitle>systemd-hwdb</refentrytitle><manvolnum>8</manvolnum></citerefentry>
and compiled to a binary database located at <filename>/etc/udev/hwdb.bin</filename>,
- or alternatively <filename>/usr/lib/udev/hwdb.bin</filename> if you want ship the compiled
- database in an immutable image.
- During runtime only the binary database is used.</para>
+ or alternatively <filename>/usr/lib/udev/hwdb.bin</filename> if you want ship the
+ compiled database in an immutable image. During runtime, only the binary database
+ is used.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Examples</title>
+
+ <example>
+ <title>General syntax of hwdb files</title>
+
+ <programlisting># /usr/lib/udev/hwdb.d/example.hwdb
+# Comments can be placed before any records. This is a good spot
+# to describe what that file is used for, what kind of properties
+# it defines, and the ordering convention.
+
+# A record with three matches and one property
+mouse:*:name:*Trackball*:
+mouse:*:name:*trackball*:
+mouse:*:name:*TrackBall*:
+ ID_INPUT_TRACKBALL=1
+
+# A record with a single match and five properties
+mouse:usb:v046dp4041:name:Logitech MX Master:
+ MOUSE_DPI=1000@166
+ MOUSE_WHEEL_CLICK_ANGLE=15
+ MOUSE_WHEEL_CLICK_ANGLE_HORIZONTAL=26
+ MOUSE_WHEEL_CLICK_COUNT=24
+ MOUSE_WHEEL_CLICK_COUNT_HORIZONTAL=14
+</programlisting>
+ </example>
+
+ <example>
+ <title>Overriding of properties</title>
+
+ <programlisting># /usr/lib/udev/hwdb.d/60-keyboard.hwdb
+evdev:atkbd:dmi:bvn*:bvr*:bd*:svnAcer*:pn*
+ KEYBOARD_KEY_a1=help
+ KEYBOARD_KEY_a2=setup
+ KEYBOARD_KEY_a3=battery
+
+evdev:atkbd:dmi:bvn*:bvr*:bd*:svnAcer*:pn123*
+ KEYBOARD_KEY_a2=wlan
+
+# /etc/udev/hwdb.d/70-keyboard.hwdb
+# disable wlan key on all at keyboards
+evdev:atkbd:*
+ KEYBOARD_KEY_a2=reserved</programlisting>
+
+ <para>If the hwdb consists of those two files, a keyboard with the lookup string
+ <literal>evdev:atkbd:dmi:bvnAcer:bdXXXXX:bd08/05/2010:svnAcer:pn123</literal>
+ will match all three records, and end up with the following properties:</para>
+
+ <programlisting>KEYBOARD_KEY_a1=help
+KEYBOARD_KEY_a2=reserved
+KEYBOARD_KEY_a3=battery</programlisting>
+ </example>
</refsect1>
<refsect1>
projects / thirdparty / systemd.git / blobdiff