xref: /third_party/alsa-utils/alsactl/alsactl_init.xml

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<article>
  <section>
    <title>alsactl init</title>
    <refentry>
      <refentryinfo>
        <title>alsactl init</title>
        <date>July 2008</date>
        <productname>alsactl</productname>
      </refentryinfo>

      <refmeta>
        <refentrytitle>alsactl_init</refentrytitle>
        <manvolnum>7</manvolnum>
        <refmiscinfo class="version"></refmiscinfo>
      </refmeta>

      <refnamediv>
        <refname>alsactl init</refname>
        <refpurpose>alsa control management - initialization</refpurpose>
      </refnamediv>

      <refsect1><title>DESCRIPTION</title>
        <para>"alsactl init" provides soundcard specific initialization.</para>
      </refsect1>

      <refsect1><title>CONFIGURATION</title>
        <para>All "alsactl init" configuration files are placed in
        <filename>/usr/share/alsa/init/</filename> directory. The top level
        configuration file is <filename>/usr/share/alsa/init/00main</filename>.
	The default top-level file can be also specified using -i or
	--initfile parameter for the alsactl tool.
	Every file consists of a set of lines of text. All empty lines or
        lines beginning with '#' will be ignored.</para>

        <refsect2><title>Rules files</title>
          <para>The "alsactl init" rules are read from the files located
          in the <filename>/usr/share/alsa/init/*</filename>. The top
          level configuration file is <filename>/usr/share/alsa/init/00main</filename>.
          Every line in the rules file contains at least one key value pair.
          There are two kind of keys, match and assignment keys. If all match
          keys are matching against its value, the rule gets applied and the
          assign keys get the specified value assigned.</para>
          
          <para>A rule may consists of a list of one or more key value pairs
          separated by a comma. Each key has a distinct operation, depending
          on the used operator. Valid operators are:</para>
          <variablelist>
            <varlistentry>
              <term><option>==</option></term>
              <listitem>
                <para>Compare for equality.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>!=</option></term>
              <listitem>
                <para>Compare for non-equality.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>=</option></term>
              <listitem>
                <para>Assign a value to a key. Keys that represent a list,
                are reset and only this single value is assigned.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>+=</option></term>
              <listitem>
                <para>Add the value to a key that holds a list
                of entries.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>:=</option></term>
              <listitem>
                <para>Assign  a  value  to  a key finally; disallow any
                later changes, which may be used to prevent changes by
                any later rules.</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>The following key names can be used to match against device
          properties:</para>
          <variablelist>
            <varlistentry>
              <term><option>CARDINDEX</option></term>
              <listitem>
                <para>Match the card index of the ALSA driver.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>CTL{<replaceable>attribute</replaceable>}</option></term>
              <listitem>
                <para>Set or test universal control attribute. Possible
		attributes:</para>
                <variablelist>
                  <varlistentry>
                    <term><option>numid</option></term>
                    <listitem>
                      <para>Numeric control identification.</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>iface</option>, <option>interface</option></term>
                    <listitem>
                      <para>Control interface name (CARD, HWEDEP, MIXER, PCM, RAWMIDI, TIMER, SEQUENCER)</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>subdev</option>, <option>subdevice</option></term>
                    <listitem>
                      <para>Subdevice number.</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>name</option></term>
                    <listitem>
                      <para>Control name</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>index</option></term>
                    <listitem>
                      <para>Control index</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>type</option></term>
                    <listitem>
                      <para>Control type (BOOLEAN, INTEGER, INTEGER64, ENUMERATED, BYTES, IEC958)</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>attr</option>, <option>attribute</option></term>
                    <listitem>
                      <para>Attributes (stored in a string - use match characters * and ?):</para>
	              <variablelist>
	                <varlistentry>
	                  <term><option>r</option></term>
	                  <listitem>
	                    <para>control is readable</para>
	                  </listitem>
	                </varlistentry>
	                <varlistentry>
	                  <term><option>w</option></term>
	                  <listitem>
	                    <para>control is writable</para>
	                  </listitem>
	                </varlistentry>
	                <varlistentry>
	                  <term><option>v</option></term>
	                  <listitem>
	                    <para>control is volatile</para>
	                  </listitem>
	                </varlistentry>
	                <varlistentry>
	                  <term><option>i</option></term>
	                  <listitem>
	                    <para>control is inactive</para>
	                  </listitem>
	                </varlistentry>
	                <varlistentry>
	                  <term><option>l</option></term>
	                  <listitem>
	                    <para>control is locked</para>
	                  </listitem>
	                </varlistentry>
	                <varlistentry>
	                  <term><option>R</option></term>
	                  <listitem>
	                    <para>control is TLV readable</para>
	                  </listitem>
	                </varlistentry>
	                <varlistentry>
	                  <term><option>W</option></term>
	                  <listitem>
	                    <para>control is TLV writable</para>
	                  </listitem>
	                </varlistentry>
	                <varlistentry>
	                  <term><option>C</option></term>
	                  <listitem>
	                    <para>control is TLV commandable</para>
	                  </listitem>
	                </varlistentry>
	                <varlistentry>
	                  <term><option>o</option></term>
	                  <listitem>
	                    <para>process is owner of this control</para>
	                  </listitem>
	                </varlistentry>
	                <varlistentry>
	                  <term><option>u</option></term>
	                  <listitem>
	                    <para>control created in user space</para>
	                  </listitem>
	                </varlistentry>
	              </variablelist>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>owner</option></term>
                    <listitem>
                      <para>Control owner process PID number</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>count</option></term>
                    <listitem>
                      <para>Control count of values</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>min</option></term>
                    <listitem>
                      <para>Value range - minimum value</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>max</option></term>
                    <listitem>
                      <para>Value range - maximum value</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>step</option></term>
                    <listitem>
                      <para>Value range - step value</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>dBmin</option></term>
                    <listitem>
                      <para>Value range - minimum dB value</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>dBmax</option></term>
                    <listitem>
                      <para>Value range - maximum dB value</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>items</option></term>
                    <listitem>
                      <para>Enumerated value - number of text items</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>enums</option></term>
                    <listitem>
                      <para>Enumerated value - list of text names stored between '|' character</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>value</option></term>
                    <listitem>
                      <para>Value of control stored to a string delimited by
                      comma (,).</para>
                    </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>do_search</option></term>
                    <listitem>
                      <para>Search for a control. Value "1" is returned
                      if a control was found. The CTL{name} key might
		      contain match characters * and ?. An control index
		      might be specified as first argument starting from
		      zero (e.g. CTL{do_search 2}="1").</para>
                     </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>do_count</option></term>
                    <listitem>
                      <para>Search for a controls and return total count
                      of matched ones. The CTL{name} key might contain match
                      characters * and ?.</para>
                     </listitem>
                  </varlistentry>
                </variablelist>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>CONFIG{sysfs_device}</option></term>
              <listitem>
                <para>The relative path to sysfs subsystem specifying
                the root directory of a soundcard device. Usually,
                it should be set to "/class/sound/card$cardinfo{card}/device".
                </para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>ATTR{<replaceable>filename</replaceable>}</option></term>
              <listitem>
                <para>Match sysfs attribute values of the soundcard device.
                The relative path to sysfs tree must be defined by
		CONFIG{sysfs_device} key. Trailing whitespace in the attribute
		values is ignored, if the specified match 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>

            <varlistentry>
              <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.
                Depending on the type of operator, this key is also used
                to export a variable to the environment.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>PROGRAM</option></term>
              <listitem>
                <para>Execute external program. The key is true, if
                the program returns without exit code zero. The whole event
                environment is available to the executed program. The
                program's output printed to stdout is available for
                the RESULT key.</para>
                <para>Several buildin commands are available:</para>
                <variablelist>
                  <varlistentry>
                    <term><option>__ctl_search</option></term>
                    <listitem>
                      <para>Search for a control. The CTL{name} key might
		      contain match characters * and ?. An control index
		      might be specified as first argument starting from
		      zero (e.g. PROGRAM="__ctl_search 2").</para>
                     </listitem>
                  </varlistentry>
                  <varlistentry>
                    <term><option>__ctl_count</option></term>
                    <listitem>
                      <para>Search for a controls and return total count
                      of matched ones. The CTL{name} key might contain match
                      characters * and ?.</para>
                     </listitem>
                  </varlistentry>
		</variablelist>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>RESULT</option></term>
              <listitem>
                <para>Match the returned string of the last PROGRAM call.
                This key can be used in the same or in any later rule
                after a PROGRAM call.</para>
              </listitem>
            </varlistentry>

          </variablelist>

          <para>Most of the fields support a shell style pattern matching.
          The following pattern characters are supported:</para>
          <variablelist>
            <varlistentry>
              <term><option>*</option></term>
              <listitem>
                <para>Matches zero, or any number of characters.</para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><option>?</option></term>
              <listitem>
                <para>Matches any single character.</para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><option>[]</option></term>
              <listitem>
                <para>Matches any single character specified within
                the brackets. For example, the pattern string 'tty[SR]'
                would match either 'ttyS' or 'ttyR'. Ranges are also
                supported within this match with the '-' character.
      		For example, to match on the range of all digits,
      		the pattern [0-9] would be used. If the first character
      		following the '[' is a '!', any characters
                not enclosed are matched.</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>The following keys can get values assigned:</para>
          <variablelist>
            <varlistentry>
              <term><option>CTL{numid}</option>, <option>CTL{iface}</option>,
		    <option>CTL{device}</option>, <option>CTL{subdev}</option>, 
		    <option>CTL{name}</option>,  <option>CTL{index}</option>, 
	      </term>
              <listitem>
              	 <para>Select universal control element.</para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><option>CTL{value}</option></term>
              <listitem>
              	 <para>Value is set (written) also to soundcard's control
              	 device and RESULT key is set to errno code. The result of
                 set operation is always true (it means continue with
                 next key on line).</para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><option>CTL{values}</option></term>
              <listitem>
              	 <para>Value is set (written) also to soundcard's control
              	 device (all control values are set to specified value) and
              	 RESULT key is set to errno code. The result of
                 set operation is always true (it means continue with
                 next key on line).</para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><option>CTL{write}</option></term>
              <listitem>
              	 <para>Value is set (written) also to soundcard's control
              	 device (all control values are set to specified value).
              	 The result of set operation is true when operation
              	 succeed (it means continue with next key on line).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>ENV{<replaceable>key</replaceable>}</option></term>
              <listitem>
                <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>

            <varlistentry>
              <term><option>RESULT</option></term>
              <listitem>
                <para>Set RESULT variable. Note that PROGRAM also sets
                this variable, but setting this variable manually
                might be useful to change code execution order (included
                files).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>LABEL</option></term>
              <listitem>
                <para>Named label where a GOTO can jump to.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>GOTO</option></term>
              <listitem>
                <para>Jumps to the next LABEL with a matching name.
                      The goto cannot jump backward.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>INCLUDE</option></term>
              <listitem>
                <para>Include the specified filename or files in specified directory.
		</para>
		<para>
		When a directory is specified, only the files with the
		extension ".conf" are read.
		Also they are read in the alphabetical order.
		Thus it's highly recommended to use some number prefix
		(e.g. "01-something.conf") to assure the order of execucions.
		</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>ACCESS</option></term>
              <listitem>
                <para>Check if specified file or directory exists</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>CONFIG{sysfs_device}</option></term>
              <listitem>
                <para>The relative path to sysfs subsystem specifying
                the root directory of a soundcard device. Usually,
                it should be set to "/class/sound/card$cardinfo{card}/device".
                </para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>PRINT</option></term>
              <listitem>
                <para>PRINT value to stdout.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>ERROR</option></term>
              <listitem>
                <para>PRINT value to stderr.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>EXIT</option></term>
              <listitem>
                <para>Exit immediately and set program exit code to value
                (should be integer). If value is "return" string,
                parser leaves current included file and returns to parent
                configuration file.</para>
              </listitem>
            </varlistentry>

          </variablelist>

          <para>The <option>PROGRAM</option>, <option>RESULT</option>,
          <option>CTL{value}</option>,
	  <option>PRINT</option>, <option>ERROR</option>,
	  <option>EXIT</option>, <option>CONFIG{}</option>
	  fields support simple printf-like string substitutions.
          It allows the use of the complete environment set by earlier matching
          rules. For all other fields, substitutions are applied while the individual rule is
          being processed. The available substitutions are:</para>
          <variablelist>
            <varlistentry>
	      <term><option>$cardinfo{<replaceable>attribute</replaceable>}</option>, <option>%i{<replaceable>attribute</replaceable>}</option></term>
              <listitem>
                <para>See CARDINFO{} for more details.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>$ctl{<replaceable>attribute</replaceable>}</option>, <option>%C{<replaceable>attribute</replaceable>}</option></term>
              <listitem>
                <para>See CTL{} for more details.</para>
              </listitem>
            </varlistentry>

            <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 device, where
                all keys of the rule have matched.
                If the attribute is a symlink, the last element of the symlink target is
                returned as the value.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>$env{<replaceable>key</replaceable>}</option>, <option>%E{<replaceable>key</replaceable>}</option></term>
              <listitem>
                <para>The value of an environment variable.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>$result</option>, <option>%c</option></term>
              <listitem>
                <para>The string returned by the external program requested with PROGRAM.
                A single part of the string, separated by a space character may be selected
                by specifying the part number as an attribute: <option>%c{N}</option>.
                If the number is followed by the '+' char this part plus all remaining parts
                of the result string are substituted: <option>%c{N+}</option></para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>$sysfsroot</option>, <option>%r</option></term>
              <listitem>
                <para>Root directory where sysfs file-system is mounted.
                Ususally, this value is just "/sys".</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>$config{<replaceable>key</replaceable>}</option>, <option>%g{<replaceable>key</replaceable>}</option></term>
              <listitem>
                <para>The value of a configuration variable. See CONFIG{} for more details.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>%%</option></term>
              <listitem>
              <para>The '%' character itself.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><option>$$</option></term>
              <listitem>
              <para>The '$' character itself.</para>
              </listitem>
            </varlistentry>
          </variablelist>
          <para>The count of characters to be substituted may be limited
          by specifying the format length value. For example, '%3s{file}'
          will only insert the first three characters of the sysfs
          attribute</para>
        </refsect2>
      </refsect1>

      <refsect1><title>AUTHOR</title>
        <para>Written by Jaroslav Kysela <email>perex@perex.cz</email></para>
        <para>Some portions are written by Greg Kroah-Hartman <email>greg@kroah.com</email> and
        Kay Sievers <email>kay.sievers@vrfy.org</email>.</para>
      </refsect1>

      <refsect1>
        <title>SEE ALSO</title>
        <para><citerefentry>
            <refentrytitle>alsactl</refentrytitle><manvolnum>1</manvolnum>
          </citerefentry></para>
      </refsect1>
    </refentry>
  </section>
</article>