cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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dv-timings.rst (1732B)


      1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
      2
      3.. _dv-timings:
      4
      5**************************
      6Digital Video (DV) Timings
      7**************************
      8
      9The video standards discussed so far have been dealing with Analog TV
     10and the corresponding video timings. Today there are many more different
     11hardware interfaces such as High Definition TV interfaces (HDMI), VGA,
     12DVI connectors etc., that carry video signals and there is a need to
     13extend the API to select the video timings for these interfaces. Since
     14it is not possible to extend the :ref:`v4l2_std_id <v4l2-std-id>`
     15due to the limited bits available, a new set of ioctls was added to
     16set/get video timings at the input and output.
     17
     18These ioctls deal with the detailed digital video timings that define
     19each video format. This includes parameters such as the active video
     20width and height, signal polarities, frontporches, backporches, sync
     21widths etc. The ``linux/v4l2-dv-timings.h`` header can be used to get
     22the timings of the formats in the :ref:`cea861` and :ref:`vesadmt`
     23standards.
     24
     25To enumerate and query the attributes of the DV timings supported by a
     26device applications use the
     27:ref:`VIDIOC_ENUM_DV_TIMINGS` and
     28:ref:`VIDIOC_DV_TIMINGS_CAP` ioctls. To set
     29DV timings for the device applications use the
     30:ref:`VIDIOC_S_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl and to get
     31current DV timings they use the
     32:ref:`VIDIOC_G_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl. To detect
     33the DV timings as seen by the video receiver applications use the
     34:ref:`VIDIOC_QUERY_DV_TIMINGS` ioctl.
     35
     36Applications can make use of the :ref:`input-capabilities` and
     37:ref:`output-capabilities` flags to determine whether the digital
     38video ioctls can be used with the given input or output.