diff options
Diffstat (limited to 'Documentation/DocBook/media/v4l/media-ioc-device-info.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/media-ioc-device-info.xml | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/v4l/media-ioc-device-info.xml b/Documentation/DocBook/media/v4l/media-ioc-device-info.xml new file mode 100644 index 00000000000..1f3237351bb --- /dev/null +++ b/Documentation/DocBook/media/v4l/media-ioc-device-info.xml @@ -0,0 +1,133 @@ +<refentry id="media-ioc-device-info"> + <refmeta> + <refentrytitle>ioctl MEDIA_IOC_DEVICE_INFO</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>MEDIA_IOC_DEVICE_INFO</refname> + <refpurpose>Query device information</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_device_info *<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_DEVICE_INFO</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>All media devices must support the <constant>MEDIA_IOC_DEVICE_INFO</constant> + ioctl. To query device information, applications call the ioctl with a + pointer to a &media-device-info;. The driver fills the structure and returns + the information to the application. + The ioctl never fails.</para> + + <table pgwide="1" frame="none" id="media-device-info"> + <title>struct <structname>media_device_info</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>char</entry> + <entry><structfield>driver</structfield>[16]</entry> + <entry><para>Name of the driver implementing the media API as a + NUL-terminated ASCII string. The driver version is stored in the + <structfield>driver_version</structfield> field.</para> + <para>Driver specific applications can use this information to + verify the driver identity. It is also useful to work around + known bugs, or to identify drivers in error reports.</para></entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>model</structfield>[32]</entry> + <entry>Device model name as a NUL-terminated UTF-8 string. The + device version is stored in the <structfield>device_version</structfield> + field and is not be appended to the model name.</entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>serial</structfield>[40]</entry> + <entry>Serial number as a NUL-terminated ASCII string.</entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>bus_info</structfield>[32]</entry> + <entry>Location of the device in the system as a NUL-terminated + ASCII string. This includes the bus type name (PCI, USB, ...) and a + bus-specific identifier.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>media_version</structfield></entry> + <entry>Media API version, formatted with the + <constant>KERNEL_VERSION()</constant> macro.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>hw_revision</structfield></entry> + <entry>Hardware device revision in a driver-specific format.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>media_version</structfield></entry> + <entry>Media device driver version, formatted with the + <constant>KERNEL_VERSION()</constant> macro. Together with the + <structfield>driver</structfield> field this identifies a particular + driver.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[31]</entry> + <entry>Reserved for future extensions. Drivers and applications must + set this array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + <para>The <structfield>serial</structfield> and <structfield>bus_info</structfield> + fields can be used to distinguish between multiple instances of otherwise + identical hardware. The serial number takes precedence when provided and can + be assumed to be unique. If the serial number is an empty string, the + <structfield>bus_info</structfield> field can be used instead. The + <structfield>bus_info</structfield> field is guaranteed to be unique, but + can vary across reboots or device unplug/replug.</para> + </refsect1> + + <refsect1> + <title>Return value</title> + <para>This function doesn't return specific error codes.</para> + </refsect1> +</refentry> |