[media] media: Links setup
Create the following ioctl and implement it at the media device level to
setup links.
- MEDIA_IOC_SETUP_LINK: Modify the properties of a given link
The only property that can currently be modified is the ENABLED link
flag to enable/disable a link. Links marked with the IMMUTABLE link flag
can not be enabled or disabled.
Enabling or disabling a link has effects on entities' use count. Those
changes are automatically propagated through the graph.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/Documentation/DocBook/v4l/media-controller.xml b/Documentation/DocBook/v4l/media-controller.xml
index 2c4fd2b..2dc25e1 100644
--- a/Documentation/DocBook/v4l/media-controller.xml
+++ b/Documentation/DocBook/v4l/media-controller.xml
@@ -85,4 +85,5 @@
&sub-media-ioc-device-info;
&sub-media-ioc-enum-entities;
&sub-media-ioc-enum-links;
+ &sub-media-ioc-setup-link;
</appendix>
diff --git a/Documentation/DocBook/v4l/media-ioc-setup-link.xml b/Documentation/DocBook/v4l/media-ioc-setup-link.xml
new file mode 100644
index 0000000..09ab3d2
--- /dev/null
+++ b/Documentation/DocBook/v4l/media-ioc-setup-link.xml
@@ -0,0 +1,90 @@
+<refentry id="media-ioc-setup-link">
+ <refmeta>
+ <refentrytitle>ioctl MEDIA_IOC_SETUP_LINK</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>MEDIA_IOC_SETUP_LINK</refname>
+ <refpurpose>Modify the properties of a link</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>int <function>ioctl</function></funcdef>
+ <paramdef>int <parameter>fd</parameter></paramdef>
+ <paramdef>int <parameter>request</parameter></paramdef>
+ <paramdef>struct media_link_desc *<parameter>argp</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Arguments</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><parameter>fd</parameter></term>
+ <listitem>
+ <para>File descriptor returned by
+ <link linkend='media-func-open'><function>open()</function></link>.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>request</parameter></term>
+ <listitem>
+ <para>MEDIA_IOC_ENUM_LINKS</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>argp</parameter></term>
+ <listitem>
+ <para></para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>To change link properties applications fill a &media-link-desc; with
+ link identification information (source and sink pad) and the new requested
+ link flags. They then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to
+ that structure.</para>
+ <para>The only configurable property is the <constant>ENABLED</constant>
+ link flag to enable/disable a link. Links marked with the
+ <constant>IMMUTABLE</constant> link flag can not be enabled or disabled.
+ </para>
+ <para>Link configuration has no side effect on other links. If an enabled
+ link at the sink pad prevents the link from being enabled, the driver
+ returns with an &EBUSY;.</para>
+ <para>If the specified link can't be found the driver returns with an
+ &EINVAL;.</para>
+ </refsect1>
+
+ <refsect1>
+ &return-value;
+
+ <variablelist>
+ <varlistentry>
+ <term><errorcode>EBUSY</errorcode></term>
+ <listitem>
+ <para>The link properties can't be changed because the link is
+ currently busy. This can be caused, for instance, by an active media
+ stream (audio or video) on the link. The ioctl shouldn't be retried if
+ no other action is performed before to fix the problem.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><errorcode>EINVAL</errorcode></term>
+ <listitem>
+ <para>The &media-link-desc; references a non-existing link, or the
+ link is immutable and an attempt to modify its configuration was made.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>