Rephrased the FIELD_ANY description: rather than explicitly list
field values, just say 'when any field format is acceptable'. The
list of FIELD values was outdated, so it was a bit confusing.
The FIELD_NONE description said that 'The driver may also indicate
this order when it cannot distinguish between V4L2_FIELD_TOP and
V4L2_FIELD_BOTTOM'. This is false, NONE really means a full frame
and userspace depends on that. So drop this line completely. There
are no drivers that do this anyway.
FIELD_TOP/BOTTOM/ALTERNATE indicate that the number of lines in the
buffer are that of a field, not frame, so returning NONE here would
cause huge problems.
Finally attempt to clarify 'progressive' and 'interlaced' a little
bit.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
---
diff --git a/Documentation/media/uapi/v4l/field-order.rst b/Documentation/media/uapi/v4l/field-order.rst
index 3fb473e3b8e2..d640e922a974 100644
--- a/Documentation/media/uapi/v4l/field-order.rst
+++ b/Documentation/media/uapi/v4l/field-order.rst
@@ -75,12 +75,11 @@ enum v4l2_field
* - ``V4L2_FIELD_ANY``
- 0
- - Applications request this field order when any one of the
- ``V4L2_FIELD_NONE``, ``V4L2_FIELD_TOP``, ``V4L2_FIELD_BOTTOM``, or
- ``V4L2_FIELD_INTERLACED`` formats is acceptable. Drivers choose
- depending on hardware capabilities or e. g. the requested image
- size, and return the actual field order. Drivers must never return
- ``V4L2_FIELD_ANY``. If multiple field orders are possible the
+ - Applications request this field order when any field format
+ is acceptable. Drivers choose depending on hardware capabilities or
+ e.g. the requested image size, and return the actual field order.
+ Drivers must never return ``V4L2_FIELD_ANY``.
+ If multiple field orders are possible the
driver must choose one of the possible field orders during
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` or
:ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>`. struct
@@ -88,9 +87,8 @@ enum v4l2_field
``V4L2_FIELD_ANY``.
* - ``V4L2_FIELD_NONE``
- 1
- - Images are in progressive format, not interlaced. The driver may
- also indicate this order when it cannot distinguish between
- ``V4L2_FIELD_TOP`` and ``V4L2_FIELD_BOTTOM``.
+ - Images are in progressive (frame-based) format, not interlaced
+ (field-based).
* - ``V4L2_FIELD_TOP``
- 2
- Images consist of the top (aka odd) field only.
