From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from claranet-outbound-smtp00.uk.clara.net ([195.8.89.33]:51687 "EHLO claranet-outbound-smtp00.uk.clara.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750703AbaJaPtV (ORCPT ); Fri, 31 Oct 2014 11:49:21 -0400 From: Simon Farnsworth To: Hans Verkuil Cc: linux-media@vger.kernel.org Subject: Re: [PATCH] DocBook media: Clarify V4L2_FIELD_ANY for drivers Date: Fri, 31 Oct 2014 15:49:12 +0000 Message-ID: <5445654.FH7TshJYAP@f19simon> In-Reply-To: <5453A289.5020007@xs4all.nl> References: <1414766908-24894-1-git-send-email-simon.farnsworth@onelan.co.uk> <5453A289.5020007@xs4all.nl> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1431848.PEoNF8zFr5"; micalg="pgp-sha1"; protocol="application/pgp-signature" Sender: linux-media-owner@vger.kernel.org List-ID: --nextPart1431848.PEoNF8zFr5 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="us-ascii" 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_F= IELD_ANY > > is only acceptable as input to the kernel, not as a response from t= he > > driver. > >=20 > > Make it clear, to stop userspace developers like me assuming it can= be > > returned by the driver. > >=20 > > Signed-off-by: Simon Farnsworth > > --- > > Documentation/DocBook/media/v4l/io.xml | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > >=20 > > 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 V4L2_FIELD_NONE, > > V4L2_FIELD_BOTTOM, or > > V4L2_FIELD_INTERLACED formats is acceptable. > > Drivers choose depending on hardware capabilities or e. g. th= e > > -requested image size, and return the actual field order. &v4l2-buf= fer; > > +requested image size, and return the actual field order. If multip= le > > +field orders are possible the driver must choose one of the possib= le > > +field orders during &VIDIOC-S-FMT; or &VIDIOC-TRY-FMT; and must no= t > > +return V4L2_FIELD_ANY. &v4l2-buffer; >=20 > I would phrase it slightly differently: >=20 > "Drivers must never return V4L2_FIELD_ANY. If mu= ltiple > field orders are possible the driver must choose one of the possible > field orders during &VIDIOC-S-FMT; or &VIDIOC-TRY-FMT;." >=20 I like your wording better than mine. v2 patch sent. =2D-=20 Simon Farnsworth Software Engineer ONELAN Ltd http://www.onelan.com --nextPart1431848.PEoNF8zFr5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. Content-Transfer-Encoding: 7Bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAABAgAGBQJUU698AAoJEOsKZy3xM+c71pUH/R2UPoxPuebc5Lvt8n9zA0Wl izf/f5Cs6xoVUSIpxsjZjH6uNDVlbgX85G2r/+51l2SfyY8W8ej/e2K8evzax8nu di/ThBu8plD5ecTlHlb0xzohozeeIeS09UIR4/WPPhLepRiJ9zRnfROrpnh0hhAM e6wykZrvpwUeiE6Eh7zlygvzhp4+E6LfMVZ0hGDEy6K755aByXVCkOQg00ZYBcrq f2QLKO7zzyJzb/OPIZ7jWlVU9cxMyLF5dRL9FA6NG2CyC+2kuJM87YAEqdAi+i2V y1/dW7bt+rOQXRR6M4ViPVRlOGXERnv9ggbkNqTXqwaP9E5l6trQ4xjGnpdvXvI= =R4w3 -----END PGP SIGNATURE----- --nextPart1431848.PEoNF8zFr5--