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Based on kernel version 3.13. Page generated on 2014-01-20 22:02 EST.

1	<refentry id="media-ioc-device-info">
2	  <refmeta>
3	    <refentrytitle>ioctl MEDIA_IOC_DEVICE_INFO</refentrytitle>
4	    &manvol;
5	  </refmeta>
6	
7	  <refnamediv>
8	    <refname>MEDIA_IOC_DEVICE_INFO</refname>
9	    <refpurpose>Query device information</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_device_info *<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_DEVICE_INFO</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>All media devices must support the <constant>MEDIA_IOC_DEVICE_INFO</constant>
53	    ioctl. To query device information, applications call the ioctl with a
54	    pointer to a &media-device-info;. The driver fills the structure and returns
55	    the information to the application.
56	    The ioctl never fails.</para>
57	
58	    <table pgwide="1" frame="none" id="media-device-info">
59	      <title>struct <structname>media_device_info</structname></title>
60	      <tgroup cols="3">
61		&cs-str;
62		<tbody valign="top">
63		  <row>
64		    <entry>char</entry>
65		    <entry><structfield>driver</structfield>[16]</entry>
66		    <entry><para>Name of the driver implementing the media API as a
67		    NUL-terminated ASCII string. The driver version is stored in the
68		    <structfield>driver_version</structfield> field.</para>
69		    <para>Driver specific applications can use this information to
70		    verify the driver identity. It is also useful to work around
71		    known bugs, or to identify drivers in error reports.</para></entry>
72		  </row>
73		  <row>
74		    <entry>char</entry>
75		    <entry><structfield>model</structfield>[32]</entry>
76		    <entry>Device model name as a NUL-terminated UTF-8 string. The
77		    device version is stored in the <structfield>device_version</structfield>
78		    field and is not be appended to the model name.</entry>
79		  </row>
80		  <row>
81		    <entry>char</entry>
82		    <entry><structfield>serial</structfield>[40]</entry>
83		    <entry>Serial number as a NUL-terminated ASCII string.</entry>
84		  </row>
85		  <row>
86		    <entry>char</entry>
87		    <entry><structfield>bus_info</structfield>[32]</entry>
88		    <entry>Location of the device in the system as a NUL-terminated
89		    ASCII string. This includes the bus type name (PCI, USB, ...) and a
90		    bus-specific identifier.</entry>
91		  </row>
92		  <row>
93		    <entry>__u32</entry>
94		    <entry><structfield>media_version</structfield></entry>
95		    <entry>Media API version, formatted with the
96		    <constant>KERNEL_VERSION()</constant> macro.</entry>
97		  </row>
98		  <row>
99		    <entry>__u32</entry>
100		    <entry><structfield>hw_revision</structfield></entry>
101		    <entry>Hardware device revision in a driver-specific format.</entry>
102		  </row>
103		  <row>
104		    <entry>__u32</entry>
105		    <entry><structfield>media_version</structfield></entry>
106		    <entry>Media device driver version, formatted with the
107		    <constant>KERNEL_VERSION()</constant> macro. Together with the
108		    <structfield>driver</structfield> field this identifies a particular
109		    driver.</entry>
110		  </row>
111		  <row>
112		    <entry>__u32</entry>
113		    <entry><structfield>reserved</structfield>[31]</entry>
114		    <entry>Reserved for future extensions. Drivers and applications must
115		    set this array to zero.</entry>
116		  </row>
117		</tbody>
118	      </tgroup>
119	    </table>
120	    <para>The <structfield>serial</structfield> and <structfield>bus_info</structfield>
121	    fields can be used to distinguish between multiple instances of otherwise
122	    identical hardware. The serial number takes precedence when provided and can
123	    be assumed to be unique. If the serial number is an empty string, the
124	    <structfield>bus_info</structfield> field can be used instead. The
125	    <structfield>bus_info</structfield> field is guaranteed to be unique, but
126	    can vary across reboots or device unplug/replug.</para>
127	  </refsect1>
128	
129	  <refsect1>
130	    &return-value;
131	  </refsect1>
132	</refentry>
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