diff --git a/doc/comedilib.xml b/doc/comedilib.xml
index 082ad83..db4dcd0 100644
--- a/doc/comedilib.xml
+++ b/doc/comedilib.xml
@@ -33,6 +33,11 @@
 			<surname>Porr</surname>
 			<email>Bernd.Porr@glasgow.ac.uk</email>
 		</author>
+		<author>
+			<firstname>Ian</firstname>
+			<surname>Abbott</surname>
+			<email>abbotti@mev.co.uk</email>
+		</author>
 		<copyright>
 			<year>1998-2003</year>
 			<holder>David Schleef</holder>
@@ -49,6 +54,10 @@
 			<year>2012</year>
 			<holder>Bernd Porr</holder>
 		</copyright>
+		<copyright>
+			<year>2012</year>
+			<holder>Ian Abbott</holder>
+		</copyright>
 
 		<abstract>
 			<para>
diff --git a/doc/other.xml b/doc/other.xml
index 9486205..cbac5f3 100644
--- a/doc/other.xml
+++ b/doc/other.xml
@@ -108,27 +108,37 @@ Multiple channels can be read and written simultaneously using the
 function
 
 <funcsynopsis><funcprototype>
-<funcdef>int <link linkend="func-ref-comedi-dio-bitfield"><function>comedi_dio_bitfield</function></link></funcdef>
+<funcdef>int <link linkend="func-ref-comedi-dio-bitfield2"><function>comedi_dio_bitfield2</function></link></funcdef>
 <paramdef><link linkend="ref-type-comedi-t">comedi_t</link> *<parameter>device</parameter></paramdef>
 <paramdef>unsigned int <parameter>subdevice</parameter></paramdef>
 <paramdef>unsigned int <parameter>write_mask</parameter></paramdef>
 <paramdef>unsigned int *<parameter>bits</parameter></paramdef>
+<paramdef>unsigned int <parameter>base_channel</parameter></paramdef>
 </funcprototype></funcsynopsis>
 
-Each channel is assigned to a bit in the
+Each channel from <parameter class="function">base_channel</parameter>
+to <parameter class="function">base_channel</parameter> &plus;
+<literal>31</literal> is assigned to a bit in the
 <parameter class="function">write_mask</parameter> and
 <parameter class="function">bits</parameter>
-bitfield.  If a bit in
+bitfield with bit 0 assigned to channel
+<parameter class="function">base_channel</parameter>, bit 1 assigned to channel
+<parameter class="function">base_channel</parameter> &plus;
+<literal>1</literal>, etc.  If a bit in
 <parameter class="function">write_mask</parameter> is set, the
 corresponding bit in <parameter class="function">*bits</parameter> will
-be written to the corresponding digital output line.
+be written to the digital output line corresponding to the channel given by
+<parameter class="function">base_channel</parameter> plus the bit number.
 Each digital line is then read and placed into
 <parameter class="function">*bits</parameter>.  The value
 of bits in <parameter class="function">*bits</parameter> corresponding
 to digital output lines is undefined and device-specific.  Channel
-<literal>0</literal> is the least significant bit in the bitfield;
-channel <literal>31</literal> is the most significant bit.  Channels
-higher than <literal>31</literal> cannot be accessed using this method.
+<parameter class="function">base_channel</parameter> &plus;
+<literal>0</literal> is the least significant bit in the bitfield.  No
+more than 32 channels at once can be accessed using this method.
+<emphasis role="strong">Warning!</emphasis> Older versions of &comedi;
+may ignore <parameter class="function">base_channel</parameter> and treat
+it as <literal>0</literal> unless the subdevice has more than 32 channels.
 </para>
 
 <para>
diff --git a/doc/tutorial.xml b/doc/tutorial.xml
index b4ccfeb..5ca284e 100644
--- a/doc/tutorial.xml
+++ b/doc/tutorial.xml
@@ -212,7 +212,7 @@
     </programlisting>
     <para>
       For advanced programmers the
-      function <link linkend="func-ref-comedi-comedi-get-buffer-contents"><function>comedi_get_buffer_contents</function></link>
+      function <link linkend="func-ref-comedi-get-buffer-contents"><function>comedi_get_buffer_contents</function></link>
       is useful to check if there is actually data in the ringbuffer
       so that a call of <function>read</function> can be avoided for example
       when the data readout is called by a timer call-back function.