From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from ffm.saftware.de ([83.141.3.46]:47940 "EHLO ffm.saftware.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754276Ab1KYMA3 (ORCPT ); Fri, 25 Nov 2011 07:00:29 -0500 Message-ID: <4ECF8359.5080705@linuxtv.org> Date: Fri, 25 Nov 2011 13:00:25 +0100 From: Andreas Oberritter MIME-Version: 1.0 To: Mauro Carvalho Chehab CC: Manu Abraham , Hans Verkuil , linux-media@vger.kernel.org, Hans Verkuil Subject: Re: [RFCv2 PATCH 12/12] Remove audio.h, video.h and osd.h. References: <1322141949-5795-1-git-send-email-hverkuil@xs4all.nl> <4ECE79F5.9000402@linuxtv.org> <201111241844.23292.hverkuil@xs4all.nl> <4ECE8839.8040606@redhat.com> <4ECE913A.9090001@redhat.com> In-Reply-To: <4ECE913A.9090001@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 24.11.2011 19:47, Mauro Carvalho Chehab wrote: > Em 24-11-2011 16:13, Manu Abraham escreveu: >> On Thu, Nov 24, 2011 at 11:38 PM, Mauro Carvalho Chehab >> wrote: >>> Em 24-11-2011 16:01, Manu Abraham escreveu: >>>> On Thu, Nov 24, 2011 at 11:14 PM, Hans Verkuil wrote: >>>>> On Thursday, November 24, 2011 18:08:05 Andreas Oberritter wrote: >>>>>> Don't break existing Userspace APIs for no reason! It's OK to add the >>>>>> new API, but - pretty please - don't just blindly remove audio.h and >>>>>> video.h. They are in use since many years by av7110, out-of-tree drivers >>>>>> *and more importantly* by applications. Yes, I know, you'd like to see >>>>>> those out-of-tree drivers merged, but it isn't possible for many >>>>>> reasons. And even if they were merged, you'd say "Port them and your >>>>>> apps to V4L". No! That's not an option. >>>>> >>>>> I'm not breaking anything. All apps will still work. >>>>> >>>>> One option (and it depends on whether people like it or not) is to have >>>>> audio.h, video.h and osd.h just include av7110.h and add a #warning >>>>> that these headers need to be replaced by the new av7110.h. >>>> >>>> >>>> That won't work with other non av7110 hardware. >>> >>> There isn't any non-av7110 driver using it at the Kernel. Anyway, we can put >>> a warning at the existing headers as-is, for now, putting them to be removed >>> for a new kernel version, like 3.4. >> >> >> No, that's not an option. The to-be merged saa716x driver depends on it. > > If the driver is not merged yet, it can be changed. > >> A DVB alone device need not depend V4L2 for it's operation. > > Why not? DVB drivers with IR should implement the input/event/IR API. DVB drivers with net > should implement the Linux Network API. DVB doesn't specify IR. There's no such thing like a DVB IR device. IP over DVB is implemented transparently. No driver needs to do anything but register its device's MAC address, therefore no driver implements the Linux Network API. > There is nothing wrong on using the ALSA API for audio and the V4L2 API for video, > as both API fits the needs for decoding audio and video streams, and new features > could be added there when needed. Yes. There's nothing wrong with it and I'm not complaining. I don't care about the implementation of the API in ivtv either. Just don't remove the API from dvb-core, period. > Duplicated API's that become legacy are removed with time. Just to mention two > notable cases, this happened with the old audio stack (OSS), with the old Wireless > stack. I can still use iwconfig and linux/wireless.h is still available on my system. ALSA still provides OSS emulation and the real OSS stack was marked deprecated but still present for ages. In contrast, you want to remove a stable API and introduce a new *completely untested* API between 3.3 and 3.4. > Do you have any issues that needs to be addressed by the V4L2 API for it to fit > on your needs? I don't want to be forced to use the V4L2 API for no reason and no gain. >> Also, it doesn't >> make any sense to have device specific headers to be used by an application, >> when drivers share more than one commonality. > > The only in-kernel driver using audio/video/osd is av7110. Once again: Manu is going to submit a new driver soon. You're trying to remove an API that you've never used. The people who use the API want it to stay. Regards, Andreas