| Laurent Pinchart | 97548ed | 2009-12-09 08:40:03 -0300 | [diff] [blame] | 1 | <refentry id="media-ioc-setup-link"> |
| 2 | <refmeta> |
| 3 | <refentrytitle>ioctl MEDIA_IOC_SETUP_LINK</refentrytitle> |
| 4 | &manvol; |
| 5 | </refmeta> |
| 6 | |
| 7 | <refnamediv> |
| 8 | <refname>MEDIA_IOC_SETUP_LINK</refname> |
| 9 | <refpurpose>Modify the properties of a link</refpurpose> |
| 10 | </refnamediv> |
| 11 | |
| 12 | <refsynopsisdiv> |
| 13 | <funcsynopsis> |
| 14 | <funcprototype> |
| 15 | <funcdef>int <function>ioctl</function></funcdef> |
| 16 | <paramdef>int <parameter>fd</parameter></paramdef> |
| 17 | <paramdef>int <parameter>request</parameter></paramdef> |
| 18 | <paramdef>struct media_link_desc *<parameter>argp</parameter></paramdef> |
| 19 | </funcprototype> |
| 20 | </funcsynopsis> |
| 21 | </refsynopsisdiv> |
| 22 | |
| 23 | <refsect1> |
| 24 | <title>Arguments</title> |
| 25 | |
| 26 | <variablelist> |
| 27 | <varlistentry> |
| 28 | <term><parameter>fd</parameter></term> |
| 29 | <listitem> |
| 30 | <para>File descriptor returned by |
| 31 | <link linkend='media-func-open'><function>open()</function></link>.</para> |
| 32 | </listitem> |
| 33 | </varlistentry> |
| 34 | <varlistentry> |
| 35 | <term><parameter>request</parameter></term> |
| 36 | <listitem> |
| Laurent Pinchart | 21d2b95 | 2011-03-17 12:23:22 -0300 | [diff] [blame] | 37 | <para>MEDIA_IOC_SETUP_LINK</para> |
| Laurent Pinchart | 97548ed | 2009-12-09 08:40:03 -0300 | [diff] [blame] | 38 | </listitem> |
| 39 | </varlistentry> |
| 40 | <varlistentry> |
| 41 | <term><parameter>argp</parameter></term> |
| 42 | <listitem> |
| 43 | <para></para> |
| 44 | </listitem> |
| 45 | </varlistentry> |
| 46 | </variablelist> |
| 47 | </refsect1> |
| 48 | |
| 49 | <refsect1> |
| 50 | <title>Description</title> |
| 51 | |
| 52 | <para>To change link properties applications fill a &media-link-desc; with |
| 53 | link identification information (source and sink pad) and the new requested |
| 54 | link flags. They then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to |
| 55 | that structure.</para> |
| 56 | <para>The only configurable property is the <constant>ENABLED</constant> |
| 57 | link flag to enable/disable a link. Links marked with the |
| 58 | <constant>IMMUTABLE</constant> link flag can not be enabled or disabled. |
| 59 | </para> |
| 60 | <para>Link configuration has no side effect on other links. If an enabled |
| 61 | link at the sink pad prevents the link from being enabled, the driver |
| 62 | returns with an &EBUSY;.</para> |
| Laurent Pinchart | e02188c | 2010-08-25 09:00:41 -0300 | [diff] [blame] | 63 | <para>Only links marked with the <constant>DYNAMIC</constant> link flag can |
| 64 | be enabled/disabled while streaming media data. Attempting to enable or |
| 65 | disable a streaming non-dynamic link will return an &EBUSY;.</para> |
| Laurent Pinchart | 97548ed | 2009-12-09 08:40:03 -0300 | [diff] [blame] | 66 | <para>If the specified link can't be found the driver returns with an |
| 67 | &EINVAL;.</para> |
| 68 | </refsect1> |
| 69 | |
| 70 | <refsect1> |
| 71 | &return-value; |
| 72 | |
| 73 | <variablelist> |
| 74 | <varlistentry> |
| 75 | <term><errorcode>EBUSY</errorcode></term> |
| 76 | <listitem> |
| 77 | <para>The link properties can't be changed because the link is |
| 78 | currently busy. This can be caused, for instance, by an active media |
| 79 | stream (audio or video) on the link. The ioctl shouldn't be retried if |
| 80 | no other action is performed before to fix the problem.</para> |
| 81 | </listitem> |
| 82 | </varlistentry> |
| 83 | <varlistentry> |
| 84 | <term><errorcode>EINVAL</errorcode></term> |
| 85 | <listitem> |
| 86 | <para>The &media-link-desc; references a non-existing link, or the |
| 87 | link is immutable and an attempt to modify its configuration was made. |
| 88 | </para> |
| 89 | </listitem> |
| 90 | </varlistentry> |
| 91 | </variablelist> |
| 92 | </refsect1> |
| 93 | </refentry> |