[media] DocBook: document when to return ENODATA

ENODATA should be returned if the API used for getting, changing, querying
or enumerating the current video timings is not supported by the current input
or output.
This was decided during the 2012 Media Workshop.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Documentation/DocBook/media/v4l/vidioc-enum-dv-presets.xml

@@ -229,6 +229,12 @@ intended for the user.</entry>
 is out of bounds.</para>
 	</listitem>
       </varlistentry>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>Digital video presets are not supported for this input or output.</para>
+	</listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 </refentry>

Documentation/DocBook/media/v4l/vidioc-enum-dv-timings.xml

@@ -106,6 +106,12 @@ application.</entry>
 is out of bounds.</para>
 	</listitem>
       </varlistentry>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>Digital video presets are not supported for this input or output.</para>
+	</listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 </refentry>

Documentation/DocBook/media/v4l/vidioc-enumstd.xml

@@ -378,6 +378,12 @@ system)</para></footnote></para></entry>
 is out of bounds.</para>
 	</listitem>
       </varlistentry>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>Standard video timings are not supported for this input or output.</para>
+	</listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 </refentry>

Documentation/DocBook/media/v4l/vidioc-g-dv-preset.xml

@@ -77,6 +77,12 @@ If the preset is not supported, it returns an &EINVAL; </para>
 <constant>VIDIOC_S_DV_PRESET</constant>,<constant>VIDIOC_S_DV_PRESET</constant> parameter was unsuitable.</para>
 	</listitem>
       </varlistentry>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>Digital video presets are not supported for this input or output.</para>
+	</listitem>
+      </varlistentry>
       <varlistentry>
 	<term><errorcode>EBUSY</errorcode></term>
 	<listitem>
@@ -104,7 +110,4 @@ If the preset is not supported, it returns an &EINVAL; </para>
       </tgroup>
     </table>
   </refsect1>
-  <refsect1>
-    &return-value;
-  </refsect1>
 </refentry>

Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml

@@ -56,7 +56,9 @@ a pointer to the &v4l2-dv-timings; structure as argument. If the ioctl is not su
 or the timing values are not correct, the driver returns &EINVAL;.</para>
 <para>The <filename>linux/v4l2-dv-timings.h</filename> header can be used to get the
 timings of the formats in the <xref linkend="cea861" /> and <xref linkend="vesadmt" />
-standards.</para>
+standards. If the current input or output does not support DV timings (e.g. if
+&VIDIOC-ENUMINPUT; does not set the <constant>V4L2_IN_CAP_CUSTOM_TIMINGS</constant> flag), then
+&ENODATA; is returned.</para>
   </refsect1>
 
   <refsect1>
@@ -70,6 +72,12 @@ standards.</para>
 <constant>VIDIOC_S_DV_TIMINGS</constant> parameter was unsuitable.</para>
 	</listitem>
       </varlistentry>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>Digital video timings are not supported for this input or output.</para>
+	</listitem>
+      </varlistentry>
       <varlistentry>
 	<term><errorcode>EBUSY</errorcode></term>
 	<listitem>
@@ -320,7 +328,4 @@ detected or used depends on the hardware.
       </tgroup>
     </table>
   </refsect1>
-  <refsect1>
-    &return-value;
-  </refsect1>
 </refentry>

Documentation/DocBook/media/v4l/vidioc-g-std.xml

@@ -72,7 +72,9 @@ flags, being a write-only ioctl it does not return the actual new standard as
 the current input does not support the requested standard the driver
 returns an &EINVAL;. When the standard set is ambiguous drivers may
 return <errorcode>EINVAL</errorcode> or choose any of the requested
-standards.</para>
+standards. If the current input or output does not support standard video timings (e.g. if
+&VIDIOC-ENUMINPUT; does not set the <constant>V4L2_IN_CAP_STD</constant> flag), then
+&ENODATA; is returned.</para>
   </refsect1>
 
   <refsect1>
@@ -85,6 +87,12 @@ standards.</para>
 	  <para>The <constant>VIDIOC_S_STD</constant> parameter was unsuitable.</para>
 	</listitem>
       </varlistentry>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>Standard video timings are not supported for this input or output.</para>
+	</listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 </refentry>

Documentation/DocBook/media/v4l/vidioc-query-dv-preset.xml

@@ -65,5 +65,14 @@ returned.</para>
 
   <refsect1>
     &return-value;
+
+    <variablelist>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>Digital video presets are not supported for this input or output.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
   </refsect1>
 </refentry>

Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml

@@ -77,6 +77,12 @@ capabilities in order to give more precise feedback to the user.
     &return-value;
 
     <variablelist>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>Digital video timings are not supported for this input or output.</para>
+	</listitem>
+      </varlistentry>
       <varlistentry>
 	<term><errorcode>ENOLINK</errorcode></term>
 	<listitem>

Documentation/DocBook/media/v4l/vidioc-querystd.xml

@@ -62,5 +62,13 @@ current video input or output.</para>
 
   <refsect1>
     &return-value;
+    <variablelist>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>Standard video timings are not supported for this input or output.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
   </refsect1>
 </refentry>