From 9fd1f310a13ab16034cbda4f874eafadc8f80caf Mon Sep 17 00:00:00 2001 From: Simon Farnsworth Date: Fri, 31 Oct 2014 12:48:42 -0300 Subject: [PATCH] [media] DocBook media: Clarify V4L2_FIELD_ANY for drivers Documentation for enum v4l2_field did not make it clear that V4L2_FIELD_ANY is only acceptable as input to the kernel, not as a response from the driver. Make it clear, to stop userspace developers like me assuming it can be returned by the driver. Signed-off-by: Simon Farnsworth Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/io.xml | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index e5e8325aa3d7..1c17f802b471 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -1422,7 +1422,10 @@ one of the V4L2_FIELD_NONE, 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. &v4l2-buffer; +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 &VIDIOC-S-FMT; or &VIDIOC-TRY-FMT;. &v4l2-buffer; field can never be V4L2_FIELD_ANY.