Commit a125385c authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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media: vidioc-g-dv-timings.rst: document V4L2_DV_FL_CAN_DETECT_REDUCED_FPS 



Document the new V4L2_DV_FL_CAN_DETECT_REDUCED_FPS flag and
update the V4L2_DV_FL_REDUCED_FPS description since it can now
also be used with receivers.

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent fb98e29f

Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst

+19 −8
Original line number Diff line number Diff line
@@ -257,14 +257,19 @@ EBUSY 
	will also be cleared. This is a read-only flag, applications must

	not set this.

    * - ``V4L2_DV_FL_REDUCED_FPS``

      - CEA-861 specific: only valid for video transmitters, the flag is

	cleared by receivers. It is also only valid for formats with the

	``V4L2_DV_FL_CAN_REDUCE_FPS`` flag set, for other formats the

	flag will be cleared by the driver. If the application sets this

	flag, then the pixelclock used to set up the transmitter is

	divided by 1.001 to make it compatible with NTSC framerates. If

	the transmitter can't generate such frequencies, then the flag

	will also be cleared.

      - CEA-861 specific: only valid for video transmitters or video

        receivers that have the ``V4L2_DV_FL_CAN_DETECT_REDUCED_FPS``

	set. This flag is cleared otherwise. It is also only valid for

	formats with the ``V4L2_DV_FL_CAN_REDUCE_FPS`` flag set, for other

	formats the flag will be cleared by the driver.



	If the application sets this flag for a transmitter, then the

	pixelclock used to set up the transmitter is divided by 1.001 to

	make it compatible with NTSC framerates. If the transmitter can't

	generate such frequencies, then the flag will be cleared.



	If a video receiver detects that the format uses a reduced framerate,

	then it will set this flag to signal this to the application.

    * - ``V4L2_DV_FL_HALF_LINE``

      - Specific to interlaced formats: if set, then the vertical

	backporch of field 1 (aka the odd field) is really one half-line
@@ -294,3 +299,9 @@ EBUSY 
      - If set, then the hdmi_vic field is valid and contains the Video

        Identification Code as per the HDMI standard (HDMI Vendor Specific

	InfoFrame).

    * - ``V4L2_DV_FL_CAN_DETECT_REDUCED_FPS``

      - CEA-861 specific: only valid for video receivers, the flag is

        cleared by transmitters.

        If set, then the hardware can detect the difference between

	regular framerates and framerates reduced by 1000/1001. E.g.:

	60 vs 59.94 Hz, 30 vs 29.97 Hz or 24 vs 23.976 Hz.