summaryrefslogtreecommitdiffstats
path: root/Documentation/DocBook/media/v4l/cec-ioc-g-mode.xml
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/DocBook/media/v4l/cec-ioc-g-mode.xml')
-rw-r--r--Documentation/DocBook/media/v4l/cec-ioc-g-mode.xml255
1 files changed, 255 insertions, 0 deletions
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>