From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:47598 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751617AbaBHR1K (ORCPT ); Sat, 8 Feb 2014 12:27:10 -0500 Message-ID: <52F669AA.30805@iki.fi> Date: Sat, 08 Feb 2014 19:30:18 +0200 From: Sakari Ailus MIME-Version: 1.0 To: Hans Verkuil 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> <52F623EF.3020003@xs4all.nl> In-Reply-To: <52F623EF.3020003@xs4all.nl> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi Hans, Thanks for the comments. Hans Verkuil wrote: > 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 Fixed. > sources. Also add a note that the SOE does not apply to outputs (there is no The flags are already documented separately, but I can add that to make it explicit. > exposure there after all). For EOF the formulation for outputs should be: > "..last pixel of the frame has been transmitted." Added. > For the COPY mode I think the SRC_MASK bits should be copied as well. That should > be stated in the documentation. Good point. I'll make that a separate patch as it changes a number of drivers. Perhaps this could be a good occasion to clean up some timecode field usage from those drivers, too. -- Kind regards, Sakari Ailus sakari.ailus@iki.fi