From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:2598 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752243Ab0IJMPA (ORCPT ); Fri, 10 Sep 2010 08:15:00 -0400 Message-ID: <4C8A2154.8090401@redhat.com> Date: Fri, 10 Sep 2010 09:15:16 -0300 From: Mauro Carvalho Chehab MIME-Version: 1.0 To: Marek Szyprowski CC: Pawel Osciak , linux-media@vger.kernel.org, kyungmin.park@samsung.com, t.fujak@samsung.com Subject: Re: [PATCH/RFC v1 0/7] Videobuf2 framework References: <1284023988-23351-1-git-send-email-p.osciak@samsung.com> <4C891F0D.2060103@redhat.com> <4C89A3EE.8040503@samsung.com> <4C89B3AD.1010404@redhat.com> <4C89E084.6090203@samsung.com> In-Reply-To: <4C89E084.6090203@samsung.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit List-ID: Sender: Mauro Carvalho Chehab Em 10-09-2010 04:38, Marek Szyprowski escreveu: > Hello, > > On 2010-09-10 13:27, Mauro Carvalho Chehab wrote: > >>>> 1) it lacks implementation of read() method. This means that vivi driver >>>> has a regression, as it currently supports it. >>> >>> Yes, read() is not yet implemented. I guess it is not a feature that would >>> be deprecated, right? >> >> Yes, there are no plans to deprecate it. Also, some devices like cx88 and bttv >> allows receiving simultaneous streams, one via mmap, and another via read(). >> This is used by some applications to allow recording video via ffmpeg/mencoder >> using read(), while the main application is displaying video using mmap. > > Well, in my opinion such devices should provide two separate /dev/videoX nodes rather than hacking with mmap and read access types. Why? V4L2 API allows to have multiple applications opening and streaming. There's nothing wrong with that, since it is a common practice in Unix to allow multiple opens for the same device. Cheers, Mauro