From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
The Video Standard section contains some awkward language. It also wasn't
updated when the error code for unimplemented ioctls changed from EINVAL
to ENOTTY.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
Documentation/DocBook/media/v4l/common.xml | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/Documentation/DocBook/media/v4l/common.xml b/Documentation/DocBook/media/v4l/common.xml
index b91d253..9378d7b 100644
--- a/Documentation/DocBook/media/v4l/common.xml
+++ b/Documentation/DocBook/media/v4l/common.xml
@@ -589,8 +589,8 @@ switch to a standard by &v4l2-std-id;.</para>
when the device has one or more video inputs or outputs.</para>
<para>Special rules apply to USB cameras where the notion of video
-standards makes little sense. More generally any capture device,
-output devices accordingly, which is <itemizedlist>
+standards makes little sense. More generally for any capture or output device
+which is: <itemizedlist>
<listitem>
<para>incapable of capturing fields or frames at the nominal
rate of the video standard, or</para>
@@ -605,17 +605,17 @@ capture time, or</para>
refer to the frames received by the driver, not the captured
frames.</para>
</listitem>
- </itemizedlist> Here the driver shall set the
+ </itemizedlist> the driver shall set the
<structfield>std</structfield> field of &v4l2-input; and &v4l2-output;
-to zero, the <constant>VIDIOC_G_STD</constant>,
+to zero and the <constant>VIDIOC_G_STD</constant>,
<constant>VIDIOC_S_STD</constant>,
<constant>VIDIOC_QUERYSTD</constant> and
<constant>VIDIOC_ENUMSTD</constant> ioctls shall return the
-&EINVAL;.<footnote>
- <para>See <xref linkend="buffer" /> for a rationale. Probably
-even USB cameras follow some well known video standard. It might have
-been better to explicitly indicate elsewhere if a device cannot live
-up to normal expectations, instead of this exception.</para>
+&ENOTTY;.<footnote>
+ <para>See <xref linkend="buffer" /> for a rationale.</para>
+ <para>Applications can make use of the <xref linkend="input-capabilities" /> and
+<xref linkend="output-capabilities"/> flags to determine whether the video standard ioctls
+are available for the device.</para>
</footnote></para>
<example>
--
1.7.10.4
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