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diff --git a/Documentation/DocBook/media/v4l/cec-ioc-g-mode.xml b/Documentation/DocBook/media/v4l/cec-ioc-g-mode.xml new file mode 100644 index 000000000000..26b4282ad134 --- /dev/null +++ b/Documentation/DocBook/media/v4l/cec-ioc-g-mode.xml @@ -0,0 +1,255 @@ +<refentry id="cec-ioc-g-mode"> + <refmeta> + <refentrytitle>ioctl CEC_G_MODE, CEC_S_MODE</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>CEC_G_MODE</refname> + <refname>CEC_S_MODE</refname> + <refpurpose>Get or set exclusive use of the CEC adapter</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>__u32 *<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='cec-func-open'><function>open()</function></link>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>CEC_G_MODE, CEC_S_MODE</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para> + Note: this documents the proposed CEC API. This API is not yet finalized and + is currently only available as a staging kernel module. + </para> + + <para>By default any filehandle can use &CEC-TRANSMIT; and &CEC-RECEIVE;, but +in order to prevent applications from stepping on each others toes it must be possible +to obtain exclusive access to the CEC adapter. This ioctl sets the filehandle +to initiator and/or follower mode which can be exclusive depending on the chosen +mode. The initiator is the filehandle that is used +to initiate messages, i.e. it commands other CEC devices. The follower is the filehandle +that receives messages sent to the CEC adapter and processes them. The same filehandle +can be both initiator and follower, or this role can be taken by two different +filehandles.</para> + + <para>When a CEC message is received, then the CEC framework will decide how +it will be processed. If the message is a reply to an earlier transmitted message, +then the reply is sent back to the filehandle that is waiting for it. In addition +the CEC framework will process it.</para> + + <para>If the message is not a reply, then the CEC framework will process it +first. If there is no follower, then the message is just discarded and a feature +abort is sent back to the initiator if the framework couldn't process it. If there +is a follower, then the message is passed on to the follower who will use +&CEC-RECEIVE; to dequeue the new message. The framework expects the follower to +make the right decisions.</para> + + <para>The CEC framework will process core messages unless requested otherwise +by the follower. The follower can enable the passthrough mode. In that case, the +CEC framework will pass on most core messages without processing them and +the follower will have to implement those messages. There are some messages +that the core will always process, regardless of the passthrough mode. See +<xref linkend="cec-core-processing" /> for details.</para> + + <para>If there is no initiator, then any CEC filehandle can use &CEC-TRANSMIT;. +If there is an exclusive initiator then only that initiator can call &CEC-TRANSMIT;. +The follower can of course always call &CEC-TRANSMIT;.</para> + + <para>Available initiator modes are:</para> + + <table pgwide="1" frame="none" id="cec-mode-initiator"> + <title>Initiator Modes</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>CEC_MODE_NO_INITIATOR</constant></entry> + <entry>0x0</entry> + <entry>This is not an initiator, i.e. it cannot transmit CEC messages + or make any other changes to the CEC adapter.</entry> + </row> + <row> + <entry><constant>CEC_MODE_INITIATOR</constant></entry> + <entry>0x1</entry> + <entry>This is an initiator (the default when the device is opened) and it + can transmit CEC messages and make changes to the CEC adapter, unless there + is an exclusive initiator.</entry> + </row> + <row> + <entry><constant>CEC_MODE_EXCL_INITIATOR</constant></entry> + <entry>0x2</entry> + <entry>This is an exclusive initiator and this file descriptor is the only one + that can transmit CEC messages and make changes to the CEC adapter. If someone + else is already the exclusive initiator then an attempt to become one will return + the &EBUSY; error.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Available follower modes are:</para> + + <table pgwide="1" frame="none" id="cec-mode-follower"> + <title>Follower Modes</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>CEC_MODE_NO_FOLLOWER</constant></entry> + <entry>0x00</entry> + <entry>This is not a follower (the default when the device is opened).</entry> + </row> + <row> + <entry><constant>CEC_MODE_FOLLOWER</constant></entry> + <entry>0x10</entry> + <entry>This is a follower and it will receive CEC messages unless there is + an exclusive follower. You cannot become a follower if <constant>CEC_CAP_TRANSMIT</constant> + is not set or if <constant>CEC_MODE_NO_INITIATOR</constant> was specified, + &EINVAL; is returned in that case.</entry> + </row> + <row> + <entry><constant>CEC_MODE_EXCL_FOLLOWER</constant></entry> + <entry>0x20</entry> + <entry>This is an exclusive follower and only this file descriptor will receive + CEC messages for processing. If someone else is already the exclusive follower + then an attempt to become one will return the &EBUSY; error. You cannot become + a follower if <constant>CEC_CAP_TRANSMIT</constant> is not set or if + <constant>CEC_MODE_NO_INITIATOR</constant> was specified, &EINVAL; is returned + in that case.</entry> + </row> + <row> + <entry><constant>CEC_MODE_EXCL_FOLLOWER_PASSTHRU</constant></entry> + <entry>0x30</entry> + <entry>This is an exclusive follower and only this file descriptor will receive + CEC messages for processing. In addition it will put the CEC device into + passthrough mode, allowing the exclusive follower to handle most core messages + instead of relying on the CEC framework for that. If someone else is already the + exclusive follower then an attempt to become one will return the &EBUSY; error. + You cannot become a follower if <constant>CEC_CAP_TRANSMIT</constant> + is not set or if <constant>CEC_MODE_NO_INITIATOR</constant> was specified, + &EINVAL; is returned in that case.</entry> + </row> + <row> + <entry><constant>CEC_MODE_MONITOR</constant></entry> + <entry>0xe0</entry> + <entry>Put the file descriptor into monitor mode. Can only be used in combination + with <constant>CEC_MODE_NO_INITIATOR</constant>, otherwise &EINVAL; will be + returned. In monitor mode all messages this CEC device transmits and all messages + it receives (both broadcast messages and directed messages for one its logical + addresses) will be reported. This is very useful for debugging. This is only + allowed if the process has the <constant>CAP_NET_ADMIN</constant> + capability. If that is not set, then &EPERM; is returned.</entry> + </row> + <row> + <entry><constant>CEC_MODE_MONITOR_ALL</constant></entry> + <entry>0xf0</entry> + <entry>Put the file descriptor into 'monitor all' mode. Can only be used in combination + with <constant>CEC_MODE_NO_INITIATOR</constant>, otherwise &EINVAL; will be + returned. In 'monitor all' mode all messages this CEC device transmits and all messages + it receives, including directed messages for other CEC devices will be reported. This + is very useful for debugging, but not all devices support this. This mode requires that + the <constant>CEC_CAP_MONITOR_ALL</constant> capability is set, otherwise &EINVAL; is + returned. This is only allowed if the process has the <constant>CAP_NET_ADMIN</constant> + capability. If that is not set, then &EPERM; is returned.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Core message processing details:</para> + + <table pgwide="1" frame="none" id="cec-core-processing"> + <title>Core Message Processing</title> + <tgroup cols="2"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>CEC_MSG_GET_CEC_VERSION</constant></entry> + <entry>When in passthrough mode this message has to be handled by userspace, + otherwise the core will return the CEC version that was set with &CEC-ADAP-S-LOG-ADDRS;.</entry> + </row> + <row> + <entry><constant>CEC_MSG_GIVE_DEVICE_VENDOR_ID</constant></entry> + <entry>When in passthrough mode this message has to be handled by userspace, + otherwise the core will return the vendor ID that was set with &CEC-ADAP-S-LOG-ADDRS;.</entry> + </row> + <row> + <entry><constant>CEC_MSG_ABORT</constant></entry> + <entry>When in passthrough mode this message has to be handled by userspace, + otherwise the core will return a feature refused message as per the specification.</entry> + </row> + <row> + <entry><constant>CEC_MSG_GIVE_PHYSICAL_ADDR</constant></entry> + <entry>When in passthrough mode this message has to be handled by userspace, + otherwise the core will report the current physical address.</entry> + </row> + <row> + <entry><constant>CEC_MSG_GIVE_OSD_NAME</constant></entry> + <entry>When in passthrough mode this message has to be handled by userspace, + otherwise the core will report the current OSD name as was set with + &CEC-ADAP-S-LOG-ADDRS;.</entry> + </row> + <row> + <entry><constant>CEC_MSG_GIVE_FEATURES</constant></entry> + <entry>When in passthrough mode this message has to be handled by userspace, + otherwise the core will report the current features as was set with + &CEC-ADAP-S-LOG-ADDRS; or the message is ignore if the CEC version was + older than 2.0.</entry> + </row> + <row> + <entry><constant>CEC_MSG_USER_CONTROL_PRESSED</constant></entry> + <entry>If <constant>CEC_CAP_RC</constant> is set, then generate a remote control + key press. This message is always passed on to userspace.</entry> + </row> + <row> + <entry><constant>CEC_MSG_USER_CONTROL_RELEASED</constant></entry> + <entry>If <constant>CEC_CAP_RC</constant> is set, then generate a remote control + key release. This message is always passed on to userspace.</entry> + </row> + <row> + <entry><constant>CEC_MSG_REPORT_PHYSICAL_ADDR</constant></entry> + <entry>The CEC framework will make note of the reported physical address + and then just pass the message on to userspace.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + </refsect1> +</refentry> |