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authorLaurent Pinchart <laurent.pinchart@ideasonboard.com>2009-12-09 06:40:01 -0500
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-03-22 03:53:14 -0400
commit1651333b09743887bc2dd3d158a11853a2be3fe7 (patch)
tree965dd31e8fbd0c866bbcd47b86baccc238101ef7 /Documentation/DocBook
parent140d88165c25137e871f9559e67986ed89251105 (diff)
[media] media: Entities, pads and links enumeration
Create the following two ioctls and implement them at the media device level to enumerate entities, pads and links. - MEDIA_IOC_ENUM_ENTITIES: Enumerate entities and their properties - MEDIA_IOC_ENUM_LINKS: Enumerate all pads and links for a given entity Entity IDs can be non-contiguous. Userspace applications should enumerate entities using the MEDIA_ENT_ID_FLAG_NEXT flag. When the flag is set in the entity ID, the MEDIA_IOC_ENUM_ENTITIES will return the next entity with an ID bigger than the requested one. Only forward links that originate at one of the entity's source pads are returned during the enumeration process. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.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>
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r--Documentation/DocBook/media-entities.tmpl8
-rw-r--r--Documentation/DocBook/v4l/media-controller.xml2
-rw-r--r--Documentation/DocBook/v4l/media-ioc-device-info.xml3
-rw-r--r--Documentation/DocBook/v4l/media-ioc-enum-entities.xml308
-rw-r--r--Documentation/DocBook/v4l/media-ioc-enum-links.xml202
5 files changed, 522 insertions, 1 deletions
diff --git a/Documentation/DocBook/media-entities.tmpl b/Documentation/DocBook/media-entities.tmpl
index 034f891399ed..2bd7b27f8553 100644
--- a/Documentation/DocBook/media-entities.tmpl
+++ b/Documentation/DocBook/media-entities.tmpl
@@ -92,6 +92,8 @@
92<!ENTITY VIDIOC-UNSUBSCRIBE-EVENT "<link linkend='vidioc-subscribe-event'><constant>VIDIOC_UNSUBSCRIBE_EVENT</constant></link>"> 92<!ENTITY VIDIOC-UNSUBSCRIBE-EVENT "<link linkend='vidioc-subscribe-event'><constant>VIDIOC_UNSUBSCRIBE_EVENT</constant></link>">
93 93
94<!ENTITY MEDIA-IOC-DEVICE-INFO "<link linkend='media-ioc-device-info'><constant>MEDIA_IOC_DEVICE_INFO</constant></link>"> 94<!ENTITY MEDIA-IOC-DEVICE-INFO "<link linkend='media-ioc-device-info'><constant>MEDIA_IOC_DEVICE_INFO</constant></link>">
95<!ENTITY MEDIA-IOC-ENUM-ENTITIES "<link linkend='media-ioc-enum-entities'><constant>MEDIA_IOC_ENUM_ENTITIES</constant></link>">
96<!ENTITY MEDIA-IOC-ENUM-LINKS "<link linkend='media-ioc-enum-links'><constant>MEDIA_IOC_ENUM_LINKS</constant></link>">
95 97
96<!-- Types --> 98<!-- Types -->
97<!ENTITY v4l2-std-id "<link linkend='v4l2-std-id'>v4l2_std_id</link>"> 99<!ENTITY v4l2-std-id "<link linkend='v4l2-std-id'>v4l2_std_id</link>">
@@ -191,6 +193,10 @@
191<!ENTITY v4l2-window "struct&nbsp;<link linkend='v4l2-window'>v4l2_window</link>"> 193<!ENTITY v4l2-window "struct&nbsp;<link linkend='v4l2-window'>v4l2_window</link>">
192 194
193<!ENTITY media-device-info "struct&nbsp;<link linkend='media-device-info'>media_device_info</link>"> 195<!ENTITY media-device-info "struct&nbsp;<link linkend='media-device-info'>media_device_info</link>">
196<!ENTITY media-entity-desc "struct&nbsp;<link linkend='media-entity-desc'>media_entity_desc</link>">
197<!ENTITY media-links-enum "struct&nbsp;<link linkend='media-links-enum'>media_links_enum</link>">
198<!ENTITY media-pad-desc "struct&nbsp;<link linkend='media-pad-desc'>media_pad_desc</link>">
199<!ENTITY media-link-desc "struct&nbsp;<link linkend='media-link-desc'>media_link_desc</link>">
194 200
195<!-- Error Codes --> 201<!-- Error Codes -->
196<!ENTITY EACCES "<errorcode>EACCES</errorcode> error code"> 202<!ENTITY EACCES "<errorcode>EACCES</errorcode> error code">
@@ -340,6 +346,8 @@
340<!ENTITY sub-media-close SYSTEM "v4l/media-func-close.xml"> 346<!ENTITY sub-media-close SYSTEM "v4l/media-func-close.xml">
341<!ENTITY sub-media-ioctl SYSTEM "v4l/media-func-ioctl.xml"> 347<!ENTITY sub-media-ioctl SYSTEM "v4l/media-func-ioctl.xml">
342<!ENTITY sub-media-ioc-device-info SYSTEM "v4l/media-ioc-device-info.xml"> 348<!ENTITY sub-media-ioc-device-info SYSTEM "v4l/media-ioc-device-info.xml">
349<!ENTITY sub-media-ioc-enum-entities SYSTEM "v4l/media-ioc-enum-entities.xml">
350<!ENTITY sub-media-ioc-enum-links SYSTEM "v4l/media-ioc-enum-links.xml">
343 351
344<!-- Function Reference --> 352<!-- Function Reference -->
345<!ENTITY close SYSTEM "v4l/func-close.xml"> 353<!ENTITY close SYSTEM "v4l/func-close.xml">
diff --git a/Documentation/DocBook/v4l/media-controller.xml b/Documentation/DocBook/v4l/media-controller.xml
index a46b786e9f2b..2c4fd2b27683 100644
--- a/Documentation/DocBook/v4l/media-controller.xml
+++ b/Documentation/DocBook/v4l/media-controller.xml
@@ -83,4 +83,6 @@
83 &sub-media-ioctl; 83 &sub-media-ioctl;
84 <!-- All ioctls go here. --> 84 <!-- All ioctls go here. -->
85 &sub-media-ioc-device-info; 85 &sub-media-ioc-device-info;
86 &sub-media-ioc-enum-entities;
87 &sub-media-ioc-enum-links;
86</appendix> 88</appendix>
diff --git a/Documentation/DocBook/v4l/media-ioc-device-info.xml b/Documentation/DocBook/v4l/media-ioc-device-info.xml
index 278a3120ee2e..1f3237351bba 100644
--- a/Documentation/DocBook/v4l/media-ioc-device-info.xml
+++ b/Documentation/DocBook/v4l/media-ioc-device-info.xml
@@ -27,7 +27,8 @@
27 <varlistentry> 27 <varlistentry>
28 <term><parameter>fd</parameter></term> 28 <term><parameter>fd</parameter></term>
29 <listitem> 29 <listitem>
30 <para>&fd;</para> 30 <para>File descriptor returned by
31 <link linkend='media-func-open'><function>open()</function></link>.</para>
31 </listitem> 32 </listitem>
32 </varlistentry> 33 </varlistentry>
33 <varlistentry> 34 <varlistentry>
diff --git a/Documentation/DocBook/v4l/media-ioc-enum-entities.xml b/Documentation/DocBook/v4l/media-ioc-enum-entities.xml
new file mode 100644
index 000000000000..13d0cc44865a
--- /dev/null
+++ b/Documentation/DocBook/v4l/media-ioc-enum-entities.xml
@@ -0,0 +1,308 @@
1<refentry id="media-ioc-enum-entities">
2 <refmeta>
3 <refentrytitle>ioctl MEDIA_IOC_ENUM_ENTITIES</refentrytitle>
4 &manvol;
5 </refmeta>
6
7 <refnamediv>
8 <refname>MEDIA_IOC_ENUM_ENTITIES</refname>
9 <refpurpose>Enumerate entities and their properties</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_entity_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>
37 <para>MEDIA_IOC_ENUM_ENTITIES</para>
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 <para>To query the attributes of an entity, applications set the id field
52 of a &media-entity-desc; structure and call the MEDIA_IOC_ENUM_ENTITIES
53 ioctl with a pointer to this structure. The driver fills the rest of the
54 structure or returns an &EINVAL; when the id is invalid.</para>
55 <para>Entities can be enumerated by or'ing the id with the
56 <constant>MEDIA_ENT_ID_FLAG_NEXT</constant> flag. The driver will return
57 information about the entity with the smallest id strictly larger than the
58 requested one ('next entity'), or the &EINVAL; if there is none.</para>
59 <para>Entity IDs can be non-contiguous. Applications must
60 <emphasis>not</emphasis> try to enumerate entities by calling
61 MEDIA_IOC_ENUM_ENTITIES with increasing id's until they get an error.</para>
62 <para>Two or more entities that share a common non-zero
63 <structfield>group_id</structfield> value are considered as logically
64 grouped. Groups are used to report
65 <itemizedlist>
66 <listitem>ALSA, VBI and video nodes that carry the same media
67 stream</listitem>
68 <listitem>lens and flash controllers associated with a sensor</listitem>
69 </itemizedlist>
70 </para>
71
72 <table pgwide="1" frame="none" id="media-entity-desc">
73 <title>struct <structname>media_entity_desc</structname></title>
74 <tgroup cols="5">
75 <colspec colname="c1" />
76 <colspec colname="c2" />
77 <colspec colname="c3" />
78 <colspec colname="c4" />
79 <colspec colname="c5" />
80 <tbody valign="top">
81 <row>
82 <entry>__u32</entry>
83 <entry><structfield>id</structfield></entry>
84 <entry></entry>
85 <entry></entry>
86 <entry>Entity id, set by the application. When the id is or'ed with
87 <constant>MEDIA_ENT_ID_FLAG_NEXT</constant>, the driver clears the
88 flag and returns the first entity with a larger id.</entry>
89 </row>
90 <row>
91 <entry>char</entry>
92 <entry><structfield>name</structfield>[32]</entry>
93 <entry></entry>
94 <entry></entry>
95 <entry>Entity name as an UTF-8 NULL-terminated string.</entry>
96 </row>
97 <row>
98 <entry>__u32</entry>
99 <entry><structfield>type</structfield></entry>
100 <entry></entry>
101 <entry></entry>
102 <entry>Entity type, see <xref linkend="media-entity-type" /> for details.</entry>
103 </row>
104 <row>
105 <entry>__u32</entry>
106 <entry><structfield>revision</structfield></entry>
107 <entry></entry>
108 <entry></entry>
109 <entry>Entity revision in a driver/hardware specific format.</entry>
110 </row>
111 <row>
112 <entry>__u32</entry>
113 <entry><structfield>flags</structfield></entry>
114 <entry></entry>
115 <entry></entry>
116 <entry>Entity flags, see <xref linkend="media-entity-flag" /> for details.</entry>
117 </row>
118 <row>
119 <entry>__u32</entry>
120 <entry><structfield>group_id</structfield></entry>
121 <entry></entry>
122 <entry></entry>
123 <entry>Entity group ID</entry>
124 </row>
125 <row>
126 <entry>__u16</entry>
127 <entry><structfield>pads</structfield></entry>
128 <entry></entry>
129 <entry></entry>
130 <entry>Number of pads</entry>
131 </row>
132 <row>
133 <entry>__u16</entry>
134 <entry><structfield>links</structfield></entry>
135 <entry></entry>
136 <entry></entry>
137 <entry>Total number of outbound links. Inbound links are not counted
138 in this field.</entry>
139 </row>
140 <row>
141 <entry>union</entry>
142 </row>
143 <row>
144 <entry></entry>
145 <entry>struct</entry>
146 <entry><structfield>v4l</structfield></entry>
147 <entry></entry>
148 <entry>Valid for V4L sub-devices and nodes only.</entry>
149 </row>
150 <row>
151 <entry></entry>
152 <entry></entry>
153 <entry>__u32</entry>
154 <entry><structfield>major</structfield></entry>
155 <entry>V4L device node major number. For V4L sub-devices with no
156 device node, set by the driver to 0.</entry>
157 </row>
158 <row>
159 <entry></entry>
160 <entry></entry>
161 <entry>__u32</entry>
162 <entry><structfield>minor</structfield></entry>
163 <entry>V4L device node minor number. For V4L sub-devices with no
164 device node, set by the driver to 0.</entry>
165 </row>
166 <row>
167 <entry></entry>
168 <entry>struct</entry>
169 <entry><structfield>fb</structfield></entry>
170 <entry></entry>
171 <entry>Valid for frame buffer nodes only.</entry>
172 </row>
173 <row>
174 <entry></entry>
175 <entry></entry>
176 <entry>__u32</entry>
177 <entry><structfield>major</structfield></entry>
178 <entry>Frame buffer device node major number.</entry>
179 </row>
180 <row>
181 <entry></entry>
182 <entry></entry>
183 <entry>__u32</entry>
184 <entry><structfield>minor</structfield></entry>
185 <entry>Frame buffer device node minor number.</entry>
186 </row>
187 <row>
188 <entry></entry>
189 <entry>struct</entry>
190 <entry><structfield>alsa</structfield></entry>
191 <entry></entry>
192 <entry>Valid for ALSA devices only.</entry>
193 </row>
194 <row>
195 <entry></entry>
196 <entry></entry>
197 <entry>__u32</entry>
198 <entry><structfield>card</structfield></entry>
199 <entry>ALSA card number</entry>
200 </row>
201 <row>
202 <entry></entry>
203 <entry></entry>
204 <entry>__u32</entry>
205 <entry><structfield>device</structfield></entry>
206 <entry>ALSA device number</entry>
207 </row>
208 <row>
209 <entry></entry>
210 <entry></entry>
211 <entry>__u32</entry>
212 <entry><structfield>subdevice</structfield></entry>
213 <entry>ALSA sub-device number</entry>
214 </row>
215 <row>
216 <entry></entry>
217 <entry>int</entry>
218 <entry><structfield>dvb</structfield></entry>
219 <entry></entry>
220 <entry>DVB card number</entry>
221 </row>
222 <row>
223 <entry></entry>
224 <entry>__u8</entry>
225 <entry><structfield>raw</structfield>[180]</entry>
226 <entry></entry>
227 <entry></entry>
228 </row>
229 </tbody>
230 </tgroup>
231 </table>
232
233 <table frame="none" pgwide="1" id="media-entity-type">
234 <title>Media entity types</title>
235 <tgroup cols="2">
236 <colspec colname="c1"/>
237 <colspec colname="c2"/>
238 <tbody valign="top">
239 <row>
240 <entry><constant>MEDIA_ENT_T_DEVNODE</constant></entry>
241 <entry>Unknown device node</entry>
242 </row>
243 <row>
244 <entry><constant>MEDIA_ENT_T_DEVNODE_V4L</constant></entry>
245 <entry>V4L video, radio or vbi device node</entry>
246 </row>
247 <row>
248 <entry><constant>MEDIA_ENT_T_DEVNODE_FB</constant></entry>
249 <entry>Frame buffer device node</entry>
250 </row>
251 <row>
252 <entry><constant>MEDIA_ENT_T_DEVNODE_ALSA</constant></entry>
253 <entry>ALSA card</entry>
254 </row>
255 <row>
256 <entry><constant>MEDIA_ENT_T_DEVNODE_DVB</constant></entry>
257 <entry>DVB card</entry>
258 </row>
259 <row>
260 <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV</constant></entry>
261 <entry>Unknown V4L sub-device</entry>
262 </row>
263 <row>
264 <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_SENSOR</constant></entry>
265 <entry>Video sensor</entry>
266 </row>
267 <row>
268 <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_FLASH</constant></entry>
269 <entry>Flash controller</entry>
270 </row>
271 <row>
272 <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_LENS</constant></entry>
273 <entry>Lens controller</entry>
274 </row>
275 </tbody>
276 </tgroup>
277 </table>
278
279 <table frame="none" pgwide="1" id="media-entity-flag">
280 <title>Media entity flags</title>
281 <tgroup cols="2">
282 <colspec colname="c1"/>
283 <colspec colname="c2"/>
284 <tbody valign="top">
285 <row>
286 <entry><constant>MEDIA_ENT_FL_DEFAULT</constant></entry>
287 <entry>Default entity for its type. Used to discover the default
288 audio, VBI and video devices, the default camera sensor, ...</entry>
289 </row>
290 </tbody>
291 </tgroup>
292 </table>
293 </refsect1>
294
295 <refsect1>
296 &return-value;
297
298 <variablelist>
299 <varlistentry>
300 <term><errorcode>EINVAL</errorcode></term>
301 <listitem>
302 <para>The &media-entity-desc; <structfield>id</structfield> references
303 a non-existing entity.</para>
304 </listitem>
305 </varlistentry>
306 </variablelist>
307 </refsect1>
308</refentry>
diff --git a/Documentation/DocBook/v4l/media-ioc-enum-links.xml b/Documentation/DocBook/v4l/media-ioc-enum-links.xml
new file mode 100644
index 000000000000..6da884159cab
--- /dev/null
+++ b/Documentation/DocBook/v4l/media-ioc-enum-links.xml
@@ -0,0 +1,202 @@
1<refentry id="media-ioc-enum-links">
2 <refmeta>
3 <refentrytitle>ioctl MEDIA_IOC_ENUM_LINKS</refentrytitle>
4 &manvol;
5 </refmeta>
6
7 <refnamediv>
8 <refname>MEDIA_IOC_ENUM_LINKS</refname>
9 <refpurpose>Enumerate all pads and links for a given entity</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_links_enum *<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>
37 <para>MEDIA_IOC_ENUM_LINKS</para>
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 enumerate pads and/or links for a given entity, applications set
53 the entity field of a &media-links-enum; structure and initialize the
54 &media-pad-desc; and &media-link-desc; structure arrays pointed by the
55 <structfield>pads</structfield> and <structfield>links</structfield> fields.
56 They then call the MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this
57 structure.</para>
58 <para>If the <structfield>pads</structfield> field is not NULL, the driver
59 fills the <structfield>pads</structfield> array with information about the
60 entity's pads. The array must have enough room to store all the entity's
61 pads. The number of pads can be retrieved with the &MEDIA-IOC-ENUM-ENTITIES;
62 ioctl.</para>
63 <para>If the <structfield>links</structfield> field is not NULL, the driver
64 fills the <structfield>links</structfield> array with information about the
65 entity's outbound links. The array must have enough room to store all the
66 entity's outbound links. The number of outbound links can be retrieved with
67 the &MEDIA-IOC-ENUM-ENTITIES; ioctl.</para>
68 <para>Only forward links that originate at one of the entity's source pads
69 are returned during the enumeration process.</para>
70
71 <table pgwide="1" frame="none" id="media-links-enum">
72 <title>struct <structname>media_links_enum</structname></title>
73 <tgroup cols="3">
74 &cs-str;
75 <tbody valign="top">
76 <row>
77 <entry>__u32</entry>
78 <entry><structfield>entity</structfield></entry>
79 <entry>Entity id, set by the application.</entry>
80 </row>
81 <row>
82 <entry>struct &media-pad-desc;</entry>
83 <entry>*<structfield>pads</structfield></entry>
84 <entry>Pointer to a pads array allocated by the application. Ignored
85 if NULL.</entry>
86 </row>
87 <row>
88 <entry>struct &media-link-desc;</entry>
89 <entry>*<structfield>links</structfield></entry>
90 <entry>Pointer to a links array allocated by the application. Ignored
91 if NULL.</entry>
92 </row>
93 </tbody>
94 </tgroup>
95 </table>
96
97 <table pgwide="1" frame="none" id="media-pad-desc">
98 <title>struct <structname>media_pad_desc</structname></title>
99 <tgroup cols="3">
100 &cs-str;
101 <tbody valign="top">
102 <row>
103 <entry>__u32</entry>
104 <entry><structfield>entity</structfield></entry>
105 <entry>ID of the entity this pad belongs to.</entry>
106 </row>
107 <row>
108 <entry>__u16</entry>
109 <entry><structfield>index</structfield></entry>
110 <entry>0-based pad index.</entry>
111 </row>
112 <row>
113 <entry>__u32</entry>
114 <entry><structfield>flags</structfield></entry>
115 <entry>Pad flags, see <xref linkend="media-pad-flag" /> for more details.</entry>
116 </row>
117 </tbody>
118 </tgroup>
119 </table>
120
121 <table frame="none" pgwide="1" id="media-pad-flag">
122 <title>Media pad flags</title>
123 <tgroup cols="2">
124 <colspec colname="c1"/>
125 <colspec colname="c2"/>
126 <tbody valign="top">
127 <row>
128 <entry><constant>MEDIA_PAD_FL_SINK</constant></entry>
129 <entry>Input pad, relative to the entity. Input pads sink data and
130 are targets of links.</entry>
131 </row>
132 <row>
133 <entry><constant>MEDIA_PAD_FL_SOURCE</constant></entry>
134 <entry>Output pad, relative to the entity. Output pads source data
135 and are origins of links.</entry>
136 </row>
137 </tbody>
138 </tgroup>
139 </table>
140
141 <table pgwide="1" frame="none" id="media-link-desc">
142 <title>struct <structname>media_links_desc</structname></title>
143 <tgroup cols="3">
144 &cs-str;
145 <tbody valign="top">
146 <row>
147 <entry>struct &media-pad-desc;</entry>
148 <entry><structfield>source</structfield></entry>
149 <entry>Pad at the origin of this link.</entry>
150 </row>
151 <row>
152 <entry>struct &media-pad-desc;</entry>
153 <entry><structfield>sink</structfield></entry>
154 <entry>Pad at the target of this link.</entry>
155 </row>
156 <row>
157 <entry>__u32</entry>
158 <entry><structfield>flags</structfield></entry>
159 <entry>Link flags, see <xref linkend="media-link-flag" /> for more details.</entry>
160 </row>
161 </tbody>
162 </tgroup>
163 </table>
164
165 <table frame="none" pgwide="1" id="media-link-flag">
166 <title>Media link flags</title>
167 <tgroup cols="2">
168 <colspec colname="c1"/>
169 <colspec colname="c2"/>
170 <tbody valign="top">
171 <row>
172 <entry><constant>MEDIA_LNK_FL_ENABLED</constant></entry>
173 <entry>The link is enabled and can be used to transfer media data.
174 When two or more links target a sink pad, only one of them can be
175 enabled at a time.</entry>
176 </row>
177 <row>
178 <entry><constant>MEDIA_LNK_FL_IMMUTABLE</constant></entry>
179 <entry>The link enabled state can't be modified at runtime. An
180 immutable link is always enabled.</entry>
181 </row>
182 </tbody>
183 </tgroup>
184 </table>
185 <para>One and only one of <constant>MEDIA_PAD_FL_SINK</constant> and
186 <constant>MEDIA_PAD_FL_SOURCE</constant> must be set for every pad.</para>
187 </refsect1>
188
189 <refsect1>
190 &return-value;
191
192 <variablelist>
193 <varlistentry>
194 <term><errorcode>EINVAL</errorcode></term>
195 <listitem>
196 <para>The &media-links-enum; <structfield>id</structfield> references
197 a non-existing entity.</para>
198 </listitem>
199 </varlistentry>
200 </variablelist>
201 </refsect1>
202</refentry>
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-19 06:15:23 -0500