1651333b09
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>
133 lines
4.6 KiB
XML
133 lines
4.6 KiB
XML
<refentry id="media-ioc-device-info">
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<refmeta>
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<refentrytitle>ioctl MEDIA_IOC_DEVICE_INFO</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname>MEDIA_IOC_DEVICE_INFO</refname>
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<refpurpose>Query device information</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcprototype>
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<funcdef>int <function>ioctl</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>int <parameter>request</parameter></paramdef>
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<paramdef>struct media_device_info *<parameter>argp</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Arguments</title>
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<variablelist>
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<varlistentry>
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<term><parameter>fd</parameter></term>
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<listitem>
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<para>File descriptor returned by
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<link linkend='media-func-open'><function>open()</function></link>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>request</parameter></term>
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<listitem>
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<para>MEDIA_IOC_DEVICE_INFO</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>argp</parameter></term>
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<listitem>
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<para></para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Description</title>
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<para>All media devices must support the <constant>MEDIA_IOC_DEVICE_INFO</constant>
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ioctl. To query device information, applications call the ioctl with a
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pointer to a &media-device-info;. The driver fills the structure and returns
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the information to the application.
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The ioctl never fails.</para>
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<table pgwide="1" frame="none" id="media-device-info">
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<title>struct <structname>media_device_info</structname></title>
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<tgroup cols="3">
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&cs-str;
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<tbody valign="top">
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<row>
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<entry>char</entry>
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<entry><structfield>driver</structfield>[16]</entry>
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<entry><para>Name of the driver implementing the media API as a
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NUL-terminated ASCII string. The driver version is stored in the
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<structfield>driver_version</structfield> field.</para>
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<para>Driver specific applications can use this information to
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verify the driver identity. It is also useful to work around
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known bugs, or to identify drivers in error reports.</para></entry>
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</row>
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<row>
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<entry>char</entry>
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<entry><structfield>model</structfield>[32]</entry>
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<entry>Device model name as a NUL-terminated UTF-8 string. The
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device version is stored in the <structfield>device_version</structfield>
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field and is not be appended to the model name.</entry>
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</row>
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<row>
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<entry>char</entry>
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<entry><structfield>serial</structfield>[40]</entry>
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<entry>Serial number as a NUL-terminated ASCII string.</entry>
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</row>
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<row>
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<entry>char</entry>
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<entry><structfield>bus_info</structfield>[32]</entry>
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<entry>Location of the device in the system as a NUL-terminated
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ASCII string. This includes the bus type name (PCI, USB, ...) and a
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bus-specific identifier.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>media_version</structfield></entry>
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<entry>Media API version, formatted with the
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<constant>KERNEL_VERSION()</constant> macro.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>hw_revision</structfield></entry>
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<entry>Hardware device revision in a driver-specific format.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>media_version</structfield></entry>
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<entry>Media device driver version, formatted with the
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<constant>KERNEL_VERSION()</constant> macro. Together with the
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<structfield>driver</structfield> field this identifies a particular
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driver.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>reserved</structfield>[31]</entry>
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<entry>Reserved for future extensions. Drivers and applications must
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set this array to zero.</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<para>The <structfield>serial</structfield> and <structfield>bus_info</structfield>
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fields can be used to distinguish between multiple instances of otherwise
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identical hardware. The serial number takes precedence when provided and can
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be assumed to be unique. If the serial number is an empty string, the
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<structfield>bus_info</structfield> field can be used instead. The
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<structfield>bus_info</structfield> field is guaranteed to be unique, but
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can vary across reboots or device unplug/replug.</para>
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</refsect1>
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<refsect1>
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<title>Return value</title>
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<para>This function doesn't return specific error codes.</para>
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</refsect1>
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</refentry>
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