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[media] V4L2 spec: document the new DV controls and ioctls

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Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2012-08-10 05:45:51 -03:00 committed by Mauro Carvalho Chehab
parent 777f4f85b7
commit 1248c7cb66
3 changed files with 202 additions and 0 deletions
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40
Documentation/DocBook/media/v4l/biblio.xml
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@ -226,4 +226,44 @@ in the frequency range from 87,5 to 108,0 MHz</title>
<title>VESA and Industry Standards and Guidelines for Computer Display Monitor Timing (DMT)</title>
</biblioentry>
<biblioentry id="vesaedid">
<abbrev>EDID</abbrev>
<authorgroup>
<corpauthor>Video Electronics Standards Association
(<ulink url="http://www.vesa.org">http://www.vesa.org</ulink>)</corpauthor>
</authorgroup>
<title>VESA Enhanced Extended Display Identification Data Standard</title>
<subtitle>Release A, Revision 2</subtitle>
</biblioentry>
<biblioentry id="hdcp">
<abbrev>HDCP</abbrev>
<authorgroup>
<corpauthor>Digital Content Protection LLC
(<ulink url="http://www.digital-cp.com">http://www.digital-cp.com</ulink>)</corpauthor>
</authorgroup>
<title>High-bandwidth Digital Content Protection System</title>
<subtitle>Revision 1.3</subtitle>
</biblioentry>
<biblioentry id="hdmi">
<abbrev>HDMI</abbrev>
<authorgroup>
<corpauthor>HDMI Licensing LLC
(<ulink url="http://www.hdmi.org">http://www.hdmi.org</ulink>)</corpauthor>
</authorgroup>
<title>High-Definition Multimedia Interface</title>
<subtitle>Specification Version 1.4a</subtitle>
</biblioentry>
<biblioentry id="dp">
<abbrev>DP</abbrev>
<authorgroup>
<corpauthor>Video Electronics Standards Association
(<ulink url="http://www.vesa.org">http://www.vesa.org</ulink>)</corpauthor>
</authorgroup>
<title>VESA DisplayPort Standard</title>
<subtitle>Version 1, Revision 2</subtitle>
</biblioentry>
</bibliography>

161
Documentation/DocBook/media/v4l/controls.xml
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@ -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 &lt;&lt; (N-8)) - (235 &lt;&lt; (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 &lt;&lt; (N-8)) - (235 &lt;&lt; (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>

1
Documentation/DocBook/media/v4l/v4l2.xml
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@ -581,6 +581,7 @@ and discussions on the V4L mailing list.</revremark>
&sub-subdev-enum-frame-size;
&sub-subdev-enum-mbus-code;
&sub-subdev-g-crop;
&sub-subdev-g-edid;
&sub-subdev-g-fmt;
&sub-subdev-g-frame-interval;
&sub-subdev-g-selection;