From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp-vbr5.xs4all.nl ([194.109.24.25]:1231 "EHLO smtp-vbr5.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750957AbaBHMdd (ORCPT ); Sat, 8 Feb 2014 07:33:33 -0500 Message-ID: <52F623EF.3020003@xs4all.nl> Date: Sat, 08 Feb 2014 13:32:47 +0100 From: Hans Verkuil MIME-Version: 1.0 To: Sakari Ailus CC: linux-media@vger.kernel.org, k.debski@samsung.com, laurent.pinchart@ideasonboard.com Subject: Re: [PATCH v4.2 4/4] v4l: Document timestamp buffer flag behaviour References: <1393149.6OyBNhdFTt@avalon> <1391813548-818-1-git-send-email-sakari.ailus@iki.fi> <1391813548-818-2-git-send-email-sakari.ailus@iki.fi> In-Reply-To: <1391813548-818-2-git-send-email-sakari.ailus@iki.fi> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 02/07/2014 11:52 PM, Sakari Ailus wrote: > Timestamp buffer flags are constant at the moment. Document them so that 1) > they're always valid and 2) not changed by the drivers. This leaves room to > extend the functionality later on if needed. > > Signed-off-by: Sakari Ailus > --- > Documentation/DocBook/media/v4l/io.xml | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml > index 451626f..f523725 100644 > --- a/Documentation/DocBook/media/v4l/io.xml > +++ b/Documentation/DocBook/media/v4l/io.xml > @@ -654,6 +654,14 @@ plane, are stored in struct v4l2_plane instead. > In that case, struct v4l2_buffer contains an array of > plane structures. > > + Buffers that have been dequeued come with timestamps. These > + timestamps can be taken from different clocks and at different part of > + the frame, depending on the driver. Please see flags in the masks > + V4L2_BUF_FLAG_TIMESTAMP_MASK and > + V4L2_BUF_FLAG_TSTAMP_SRC_MASK in + linkend="buffer-flags">. These flags are guaranteed to be always valid > + and will not be changed by the driver. That's a bit too strong. Different inputs or outputs may have different timestamp sources. Also add a note that the SOE does not apply to outputs (there is no exposure there after all). For EOF the formulation for outputs should be: "..last pixel of the frame has been transmitted." For the COPY mode I think the SRC_MASK bits should be copied as well. That should be stated in the documentation. Regards, Hans > + > > struct <structname>v4l2_buffer</structname> > >