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diff --git a/man/hwdb.xml b/man/hwdb.xml new file mode 100644 index 0000000..7d550c6 --- /dev/null +++ b/man/hwdb.xml @@ -0,0 +1,135 @@ +<?xml version='1.0'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + +<!-- + SPDX-License-Identifier: LGPL-2.1+ +--> + +<refentry id="hwdb" conditional="ENABLE_HWDB"> + <refentryinfo> + <title>hwdb</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>hwdb</refentrytitle> + <manvolnum>7</manvolnum> + </refmeta> + + <refnamediv> + <refname>hwdb</refname> + <refpurpose>Hardware Database</refpurpose> + </refnamediv> + + <refsect1><title>Description</title> + <para>The hardware database is a key-value store for associating modalias-like keys to + 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> 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 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 that hwdb file entirely. hwdb files must have the extension + <filename>.hwdb</filename>; other extensions are ignored.</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>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> + </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> + <title>See Also</title> + <para> + <citerefentry> + <refentrytitle>systemd-hwdb</refentrytitle><manvolnum>8</manvolnum> + </citerefentry> + </para> + </refsect1> +</refentry> |