</table>
</section>
+
+ <section id="dv-controls">
+ <title>Digital Video Control Reference</title>
+
+ <note>
+ <title>Experimental</title>
+
+ <para>This is an <link
+ linkend="experimental">experimental</link> interface and may
+ change in the future.</para>
+ </note>
+
+ <para>
+ The Digital Video control class is intended to control receivers
+ and transmitters for <ulink url="http://en.wikipedia.org/wiki/Vga">VGA</ulink>,
+ <ulink url="http://en.wikipedia.org/wiki/Digital_Visual_Interface">DVI</ulink>
+ (Digital Visual Interface), HDMI (<xref linkend="hdmi" />) and DisplayPort (<xref linkend="dp" />).
+ These controls are generally expected to be private to the receiver or transmitter
+ subdevice that implements them, so they are only exposed on the
+ <filename>/dev/v4l-subdev*</filename> device node.
+ </para>
+
+ <para>Note that these devices can have multiple input or output pads which are
+ hooked up to e.g. HDMI connectors. Even though the subdevice will receive or
+ transmit video from/to only one of those pads, the other pads can still be
+ active when it comes to EDID (Extended Display Identification Data,
+ <xref linkend="vesaedid" />) and HDCP (High-bandwidth Digital Content
+ Protection System, <xref linkend="hdcp" />) processing, allowing the device
+ to do the fairly slow EDID/HDCP handling in advance. This allows for quick
+ switching between connectors.</para>
+
+ <para>These pads appear in several of the controls in this section as
+ bitmasks, one bit for each pad. Bit 0 corresponds to pad 0, bit 1 to pad 1,
+ etc. The maximum value of the control is the set of valid pads.</para>
+
+ <table pgwide="1" frame="none" id="dv-control-id">
+ <title>Digital Video Control IDs</title>
+
+ <tgroup cols="4">
+ <colspec colname="c1" colwidth="1*" />
+ <colspec colname="c2" colwidth="6*" />
+ <colspec colname="c3" colwidth="2*" />
+ <colspec colname="c4" colwidth="6*" />
+ <spanspec namest="c1" nameend="c2" spanname="id" />
+ <spanspec namest="c2" nameend="c4" spanname="descr" />
+ <thead>
+ <row>
+ <entry spanname="id" align="left">ID</entry>
+ <entry align="left">Type</entry>
+ </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
+ </row>
+ </thead>
+ <tbody valign="top">
+ <row><entry></entry></row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_DV_CLASS</constant></entry>
+ <entry>class</entry>
+ </row>
+ <row>
+ <entry spanname="descr">The Digital Video class descriptor.</entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_DV_TX_HOTPLUG</constant></entry>
+ <entry>bitmask</entry>
+ </row>
+ <row>
+ <entry spanname="descr">Many connectors have a hotplug pin which is high
+ if EDID information is available from the source. This control shows the
+ state of the hotplug pin as seen by the transmitter.
+ Each bit corresponds to an output pad on the transmitter. If an output pad
+ does not have an associated hotplug pin, then the bit for that pad will be 0.
+ This read-only control is applicable to DVI-D, HDMI and DisplayPort connectors.
+ </entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_DV_TX_RXSENSE</constant></entry>
+ <entry>bitmask</entry>
+ </row>
+ <row>
+ <entry spanname="descr">Rx Sense is the detection of pull-ups on the TMDS
+ clock lines. This normally means that the sink has left/entered standby (i.e.
+ the transmitter can sense that the receiver is ready to receive video).
+ Each bit corresponds to an output pad on the transmitter. If an output pad
+ does not have an associated Rx Sense, then the bit for that pad will be 0.
+ This read-only control is applicable to DVI-D and HDMI devices.
+ </entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_DV_TX_EDID_PRESENT</constant></entry>
+ <entry>bitmask</entry>
+ </row>
+ <row>
+ <entry spanname="descr">When the transmitter sees the hotplug signal from the
+ receiver it will attempt to read the EDID. If set, then the transmitter has read
+ at least the first block (= 128 bytes).
+ Each bit corresponds to an output pad on the transmitter. If an output pad
+ does not support EDIDs, then the bit for that pad will be 0.
+ This read-only control is applicable to VGA, DVI-A/D, HDMI and DisplayPort connectors.
+ </entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_DV_TX_MODE</constant></entry>
+ <entry id="v4l2-dv-tx-mode">enum v4l2_dv_tx_mode</entry>
+ </row>
+ <row>
+ <entry spanname="descr">HDMI transmitters can transmit in DVI-D mode (just video)
+ or in HDMI mode (video + audio + auxiliary data). This control selects which mode
+ to use: V4L2_DV_TX_MODE_DVI_D or V4L2_DV_TX_MODE_HDMI.
+ This control is applicable to HDMI connectors.
+ </entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_DV_TX_RGB_RANGE</constant></entry>
+ <entry id="v4l2-dv-rgb-range">enum v4l2_dv_rgb_range</entry>
+ </row>
+ <row>
+ <entry spanname="descr">Select the quantization range for RGB output. V4L2_DV_RANGE_AUTO
+ follows the RGB quantization range specified in the standard for the video interface
+ (ie. <xref linkend="cea861" /> for HDMI). V4L2_DV_RANGE_LIMITED and V4L2_DV_RANGE_FULL override the standard
+ to be compatible with sinks that have not implemented the standard correctly
+ (unfortunately quite common for HDMI and DVI-D). Full range allows all possible values to be
+ used whereas limited range sets the range to (16 << (N-8)) - (235 << (N-8))
+ where N is the number of bits per component.
+ This control is applicable to VGA, DVI-A/D, HDMI and DisplayPort connectors.
+ </entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_DV_RX_POWER_PRESENT</constant></entry>
+ <entry>bitmask</entry>
+ </row>
+ <row>
+ <entry spanname="descr">Detects whether the receiver receives power from the source
+ (e.g. HDMI carries 5V on one of the pins). This is often used to power an eeprom
+ which contains EDID information, such that the source can read the EDID even if
+ the sink is in standby/power off.
+ Each bit corresponds to an input pad on the transmitter. If an input pad
+ cannot detect whether power is present, then the bit for that pad will be 0.
+ This read-only control is applicable to DVI-D, HDMI and DisplayPort connectors.
+ </entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_DV_RX_RGB_RANGE</constant></entry>
+ <entry>enum v4l2_dv_rgb_range</entry>
+ </row>
+ <row>
+ <entry spanname="descr">Select the quantization range for RGB input. V4L2_DV_RANGE_AUTO
+ follows the RGB quantization range specified in the standard for the video interface
+ (ie. <xref linkend="cea861" /> for HDMI). V4L2_DV_RANGE_LIMITED and V4L2_DV_RANGE_FULL override the standard
+ to be compatible with sources that have not implemented the standard correctly
+ (unfortunately quite common for HDMI and DVI-D). Full range allows all possible values to be
+ used whereas limited range sets the range to (16 << (N-8)) - (235 << (N-8))
+ where N is the number of bits per component.
+ This control is applicable to VGA, DVI-A/D, HDMI and DisplayPort connectors.
+ </entry>
+ </row>
+ <row><entry></entry></row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </section>
</section>
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