| Message ID | 1414766908-24894-1-git-send-email-simon.farnsworth@onelan.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Friday 31 October 2014 15:54:01 Hans Verkuil wrote: > On 10/31/2014 03:48 PM, Simon Farnsworth wrote: > > 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 <simon.farnsworth@onelan.co.uk> > > --- > > 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 e5e8325..8918bb2 100644 > > --- a/Documentation/DocBook/media/v4l/io.xml > > +++ b/Documentation/DocBook/media/v4l/io.xml > > @@ -1422,7 +1422,10 @@ one of the <constant>V4L2_FIELD_NONE</constant>, > > <constant>V4L2_FIELD_BOTTOM</constant>, or > > <constant>V4L2_FIELD_INTERLACED</constant> 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. If multiple > > +field orders are possible the driver must choose one of the possible > > +field orders during &VIDIOC-S-FMT; or &VIDIOC-TRY-FMT; and must not > > +return V4L2_FIELD_ANY. &v4l2-buffer; > > I would phrase it slightly differently: > > "Drivers must never return <constant>V4L2_FIELD_ANY</constant>. If multiple > field orders are possible the driver must choose one of the possible > field orders during &VIDIOC-S-FMT; or &VIDIOC-TRY-FMT;." > I like your wording better than mine. v2 patch sent.
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index e5e8325..8918bb2 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -1422,7 +1422,10 @@ one of the <constant>V4L2_FIELD_NONE</constant>, <constant>V4L2_FIELD_BOTTOM</constant>, or <constant>V4L2_FIELD_INTERLACED</constant> 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. If multiple +field orders are possible the driver must choose one of the possible +field orders during &VIDIOC-S-FMT; or &VIDIOC-TRY-FMT; and must not +return V4L2_FIELD_ANY. &v4l2-buffer; <structfield>field</structfield> can never be <constant>V4L2_FIELD_ANY</constant>.</entry> </row>
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 <simon.farnsworth@onelan.co.uk> --- Documentation/DocBook/media/v4l/io.xml | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)