140d88165c
Create the following ioctl and implement it at the media device level to query device information. - MEDIA_IOC_DEVICE_INFO: Query media device information The ioctl and its data structure are defined in the new kernel header linux/media.h available to userspace applications. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
94 lines
2.8 KiB
XML
94 lines
2.8 KiB
XML
<refentry id="media-func-open">
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<refmeta>
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<refentrytitle>media open()</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname>media-open</refname>
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<refpurpose>Open a media device</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <fcntl.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>open</function></funcdef>
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<paramdef>const char *<parameter>device_name</parameter></paramdef>
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<paramdef>int <parameter>flags</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>device_name</parameter></term>
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<listitem>
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<para>Device to be opened.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>flags</parameter></term>
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<listitem>
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<para>Open flags. Access mode must be either <constant>O_RDONLY</constant>
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or <constant>O_RDWR</constant>. Other flags have no effect.</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>To open a media device applications call <function>open()</function>
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with the desired device name. The function has no side effects; the device
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configuration remain unchanged.</para>
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<para>When the device is opened in read-only mode, attemps to modify its
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configuration will result in an error, and <varname>errno</varname> will be
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set to <errorcode>EBADF</errorcode>.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para><function>open</function> returns the new file descriptor on success.
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On error, -1 is returned, and <varname>errno</varname> is set appropriately.
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Possible error codes are:</para>
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<variablelist>
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<varlistentry>
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<term><errorcode>EACCES</errorcode></term>
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<listitem>
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<para>The requested access to the file is not allowed.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><errorcode>EMFILE</errorcode></term>
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<listitem>
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<para>The process already has the maximum number of files open.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><errorcode>ENFILE</errorcode></term>
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<listitem>
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<para>The system limit on the total number of open files has been
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reached.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><errorcode>ENOMEM</errorcode></term>
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<listitem>
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<para>Insufficient kernel memory was available.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><errorcode>ENXIO</errorcode></term>
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<listitem>
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<para>No device corresponding to this device special file exists.
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</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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</refentry>
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