Commit | Line | Data |
---|---|---|
97548ed4 LP |
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> | |
21d2b958 | 37 | <para>MEDIA_IOC_SETUP_LINK</para> |
97548ed4 LP |
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> | |
e02188c9 LP |
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> | |
97548ed4 LP |
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> |