Based on kernel version 4.7.2. Page generated on 2016-08-22 22:45 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>driver_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>
