From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:38878 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751908Ab2HMTQD (ORCPT ); Mon, 13 Aug 2012 15:16:03 -0400 Received: by bkwj10 with SMTP id j10so1457114bkw.19 for ; Mon, 13 Aug 2012 12:16:01 -0700 (PDT) Message-ID: <5029526E.7020605@gmail.com> Date: Mon, 13 Aug 2012 21:15:58 +0200 From: Sylwester Nawrocki MIME-Version: 1.0 To: Hans de Goede , Hans Verkuil CC: linux-media , workshop-2011@linuxtv.org Subject: Re: [Workshop-2011] RFC: V4L2 API ambiguities References: <201208131427.56961.hverkuil@xs4all.nl> <5028FD7E.1010402@redhat.com> In-Reply-To: <5028FD7E.1010402@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi! On 08/13/2012 03:13 PM, Hans de Goede wrote: >> 2) If a driver supports only formats with more than one plane, should >> V4L2_CAP_VIDEO_CAPTURE still be defined? > > No Agreed. >> And if a driver also supports >> single-plane formats in addition to >1 plane formats, should >> V4L2_CAP_VIDEO_CAPTURE be compulsary? > > Yes, so that non multi-plane aware apps keep working. There is the multi-planar API and there are multi-planar formats. Single- and multi-planar formats can be handled with the multi-planar API. So if a driver supports single- and multi-planar formats by means on multi-planar APIs, there shouldn't be a need for signalling V4L2_CAP_VIDEO_CAPTURE, which normally indicates single-planar API. The driver may choose to not support it, in order to handle single-planar formats. Thus, in my opinion making V4L2_CAP_VIDEO_CAPTURE compulsory wouldn't make sense. Unless the driver supports both types of ioctls (_mplane and regular versions), we shouldn't flag V4L2_CAP_VIDEO_CAPTURE. Regards, Sylwester