diff --git a/man/udev.xml b/man/udev.xml
index 3cf3c7f5b..69be5d19c 100644
--- a/man/udev.xml
+++ b/man/udev.xml
@@ -762,6 +762,43 @@
During runtime only the binary database is used.
+ Hardware Database Files
+ The hwdb files are read from the files located in the
+ system hwdb directory /usr/lib/udev/hwdb.d,
+ the volatile runtime directory /run/udev/hwdb.d
+ and the local administration directory /etc/udev/hwdb.d.
+ 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 /etc
+ have the highest priority, files in /run take precedence
+ over files with the same name in /usr/lib. This can be
+ used to override a system-supplied hwdb file with a local file if needed;
+ a symlink in /etc with the same name as a hwdb file in
+ /usr/lib, pointing to /dev/null,
+ disables the hwdb file entirely. hwdb files must have the extension
+ .hwdb; other extensions are ignored.
+
+ 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.
+
+ 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 =. An empty line signifies the end
+ of a record. Lines beginning with # are ignored.
+
+ The content of all hwdb files is read by
+ udevadm8
+ and compiled to a binary database located at /etc/udev/hwdb.bin,
+ or alternatively /usr/lib/udev/hwdb.bin if you want ship the compiled
+ database in an immutable image.
+ During runtime only the binary database is used.
+
+
See Also