udevd: add --debug-trace option

[elogind.git] / udev.xml

diff --git a/udev.xml b/udev.xml
index 84341565300d6f02b8136cab04cb71854d66e066..852ae039e7117282ab5f0fae8d46ef8ef5317d07 100644 (file)
--- a/udev.xml
+++ b/udev.xml
@@ -174,7 +174,9 @@
                 <para>Match sysfs attribute values of the event device. Up to five
                 <option>ATTR</option> keys can be specified per rule. Trailing
                 whitespace in the attribute values is ignored, if the specified match
-                value does not contain trailing whitespace itself.</para>
+                value does not contain trailing whitespace itself. Depending on the type
+                of operator, this key is also used to set the value of a sysfs attribute.
+                </para>
               </listitem>
             </varlistentry>
 
@@ -213,8 +215,8 @@
               <term><option>ENV{<replaceable>key</replaceable>}</option></term>
               <listitem>
                 <para>Match against the value of an environment variable. Up to five <option>ENV</option>
-                keys can be specified per rule. This key can also be used to export a variable to
-                the environment.</para>
+                keys can be specified per rule. Depending on the type of operator, this key is also used
+                to export a variable to the environment.</para>
               </listitem>
             </varlistentry>
 
@@ -294,11 +296,20 @@
               </listitem>
             </varlistentry>
 
+            <varlistentry>
+              <term><option>ATTR{<replaceable>key</replaceable>}</option></term>
+              <listitem>
+                <para>The value that should be written to a sysfs attribute of the
+                event device. Depending on the type of operator, this key is also
+                used to match against the value of a sysfs attribute.</para>
+              </listitem>
+            </varlistentry>
+
             <varlistentry>
               <term><option>ENV{<replaceable>key</replaceable>}</option></term>
               <listitem>
-                <para>Export a variable to the environment. This key can also be used to match
-                against an environment variable.</para>
+                <para>Export a variable to the environment. Depending on the type of operator,
+                this key is also to match against an environment variable.</para>
               </listitem>
             </varlistentry>
 
@@ -395,7 +406,7 @@
               <term><option>$id</option>, <option>%b</option></term>
               <listitem>
                 <para>The name of the device matched while searching the devpath upwards for
-                  <option>SUBSYSTEMS</option>, <option>KERNELS</option> <option>DRIVERS</option> and <option>ATTRS</option>.
+                  <option>SUBSYSTEMS</option>, <option>KERNELS</option>, <option>DRIVERS</option> and <option>ATTRS</option>.
                 </para>
               </listitem>
             </varlistentry>
@@ -403,7 +414,12 @@
             <varlistentry>
               <term><option>$attr{<replaceable>file</replaceable>}</option>, <option>%s{<replaceable>file</replaceable>}</option></term>
               <listitem>
-                <para>The value of a sysfs attribute found at the current or a parent device.</para>
+                <para>The value of a sysfs attribute found at the device, where
+                all keys of the rule have matched. If the matching device does not have
+                such an attribute, all devices along the chain of parents are searched
+                for a matching attribute.
+                If the attribute is a symlink, the last element of the symlink target is
+                returned as the value.</para>
               </listitem>
             </varlistentry>