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diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index 93b9c6872e53..272a5f718509 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -4273,4 +4273,165 @@ interface and may change in the future.</para> </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> |