1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
|
<refentry id="media-ioc-enum-entities">
<refmeta>
<refentrytitle>ioctl MEDIA_IOC_ENUM_ENTITIES</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>MEDIA_IOC_ENUM_ENTITIES</refname>
<refpurpose>Enumerate entities and their properties</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_entity_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_ENTITIES</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>To query the attributes of an entity, applications set the id field
of a &media-entity-desc; structure and call the MEDIA_IOC_ENUM_ENTITIES
ioctl with a pointer to this structure. The driver fills the rest of the
structure or returns an &EINVAL; when the id is invalid.</para>
<para>Entities can be enumerated by or'ing the id with the
<constant>MEDIA_ENT_ID_FLAG_NEXT</constant> flag. The driver will return
information about the entity with the smallest id strictly larger than the
requested one ('next entity'), or the &EINVAL; if there is none.</para>
<para>Entity IDs can be non-contiguous. Applications must
<emphasis>not</emphasis> try to enumerate entities by calling
MEDIA_IOC_ENUM_ENTITIES with increasing id's until they get an error.</para>
<para>Two or more entities that share a common non-zero
<structfield>group_id</structfield> value are considered as logically
grouped. Groups are used to report
<itemizedlist>
<listitem><para>ALSA, VBI and video nodes that carry the same media
stream</para></listitem>
<listitem><para>lens and flash controllers associated with a sensor</para></listitem>
</itemizedlist>
</para>
<table pgwide="1" frame="none" id="media-entity-desc">
<title>struct <structname>media_entity_desc</structname></title>
<tgroup cols="5">
<colspec colname="c1" />
<colspec colname="c2" />
<colspec colname="c3" />
<colspec colname="c4" />
<colspec colname="c5" />
<tbody valign="top">
<row>
<entry>__u32</entry>
<entry><structfield>id</structfield></entry>
<entry></entry>
<entry></entry>
<entry>Entity id, set by the application. When the id is or'ed with
<constant>MEDIA_ENT_ID_FLAG_NEXT</constant>, the driver clears the
flag and returns the first entity with a larger id.</entry>
</row>
<row>
<entry>char</entry>
<entry><structfield>name</structfield>[32]</entry>
<entry></entry>
<entry></entry>
<entry>Entity name as an UTF-8 NULL-terminated string.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>type</structfield></entry>
<entry></entry>
<entry></entry>
<entry>Entity type, see <xref linkend="media-entity-type" /> for details.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>revision</structfield></entry>
<entry></entry>
<entry></entry>
<entry>Entity revision in a driver/hardware specific format.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>flags</structfield></entry>
<entry></entry>
<entry></entry>
<entry>Entity flags, see <xref linkend="media-entity-flag" /> for details.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>group_id</structfield></entry>
<entry></entry>
<entry></entry>
<entry>Entity group ID</entry>
</row>
<row>
<entry>__u16</entry>
<entry><structfield>pads</structfield></entry>
<entry></entry>
<entry></entry>
<entry>Number of pads</entry>
</row>
<row>
<entry>__u16</entry>
<entry><structfield>links</structfield></entry>
<entry></entry>
<entry></entry>
<entry>Total number of outbound links. Inbound links are not counted
in this field.</entry>
</row>
<row>
<entry>union</entry>
</row>
<row>
<entry></entry>
<entry>struct</entry>
<entry><structfield>dev</structfield></entry>
<entry></entry>
<entry>Valid for (sub-)devices that create a single device node.</entry>
</row>
<row>
<entry></entry>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>major</structfield></entry>
<entry>Device node major number.</entry>
</row>
<row>
<entry></entry>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>minor</structfield></entry>
<entry>Device node minor number.</entry>
</row>
<row>
<entry></entry>
<entry>__u8</entry>
<entry><structfield>raw</structfield>[184]</entry>
<entry></entry>
<entry></entry>
</row>
</tbody>
</tgroup>
</table>
<table frame="none" pgwide="1" id="media-entity-type">
<title>Media entity types</title>
<tgroup cols="2">
<colspec colname="c1"/>
<colspec colname="c2"/>
<tbody valign="top">
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE</constant></entry>
<entry>Unknown device node</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_V4L</constant></entry>
<entry>V4L video, radio or vbi device node</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_FB</constant></entry>
<entry>Frame buffer device node</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_ALSA</constant></entry>
<entry>ALSA card</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_FE</constant></entry>
<entry>DVB frontend devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_DEMUX</constant></entry>
<entry>DVB demux devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_DVR</constant></entry>
<entry>DVB DVR devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_CA</constant></entry>
<entry>DVB CAM devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_NET</constant></entry>
<entry>DVB network devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV</constant></entry>
<entry>Unknown V4L sub-device</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_SENSOR</constant></entry>
<entry>Video sensor</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_FLASH</constant></entry>
<entry>Flash controller</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_LENS</constant></entry>
<entry>Lens controller</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_DECODER</constant></entry>
<entry>Video decoder, the basic function of the video decoder is to
accept analogue video from a wide variety of sources such as
broadcast, DVD players, cameras and video cassette recorders, in
either NTSC, PAL or HD format and still occasionally SECAM, separate
it into its component parts, luminance and chrominance, and output
it in some digital video standard, with appropriate embedded timing
signals.</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_TUNER</constant></entry>
<entry>TV and/or radio tuner</entry>
</row>
</tbody>
</tgroup>
</table>
<table frame="none" pgwide="1" id="media-entity-flag">
<title>Media entity flags</title>
<tgroup cols="2">
<colspec colname="c1"/>
<colspec colname="c2"/>
<tbody valign="top">
<row>
<entry><constant>MEDIA_ENT_FL_DEFAULT</constant></entry>
<entry>Default entity for its type. Used to discover the default
audio, VBI and video devices, the default camera sensor, ...</entry>
</row>
</tbody>
</tgroup>
</table>
</refsect1>
<refsect1>
&return-value;
<variablelist>
<varlistentry>
<term><errorcode>EINVAL</errorcode></term>
<listitem>
<para>The &media-entity-desc; <structfield>id</structfield> references
a non-existing entity.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
|
