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Wed, 2 Aug 2023 12:08:35 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id WG4jNUNHymR8PwAAMHmgww (envelope-from ); Wed, 02 Aug 2023 12:08:35 +0000 Date: Wed, 02 Aug 2023 14:08:35 +0200 Message-ID: <87il9xoddo.wl-tiwai@suse.de> From: Takashi Iwai To: Shengjiu Wang Subject: Re: [RFC PATCH v2 0/7] Add audio support in v4l2 framework In-Reply-To: References: <1690265540-25999-1-git-send-email-shengjiu.wang@nxp.com> <47d66c28-1eb2-07f5-d6f9-779d675aefe8@xs4all.nl> <87il9xu1ro.wl-tiwai@suse.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: nicoleotsuka@gmail.com, alsa-devel@alsa-project.org, lgirdwood@gmail.com, Xiubo.Lee@gmail.com, linux-kernel@vger.kernel.org, Shengjiu Wang , tiwai@suse.com, linux-media@vger.kernel.org, tfiga@chromium.org, Hans Verkuil , linuxppc-dev@lists.ozlabs.org, broonie@kernel.org, sakari.ailus@iki.fi, perex@perex.cz, mchehab@kernel.org, festevam@gmail.com, m.szyprowski@samsung.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, 02 Aug 2023 14:02:29 +0200, Shengjiu Wang wrote: > > On Wed, Aug 2, 2023 at 7:22 PM Takashi Iwai wrote: > > > > On Wed, 02 Aug 2023 09:32:37 +0200, > > Hans Verkuil wrote: > > > > > > Hi all, > > > > > > On 25/07/2023 08:12, Shengjiu Wang wrote: > > > > Audio signal processing has the requirement for memory to > > > > memory similar as Video. > > > > > > > > This patch is to add this support in v4l2 framework, defined > > > > new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and > > > > V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format > > > > for audio case usage. > > > > > > > > The created audio device is named "/dev/audioX". > > > > > > > > And add memory to memory support for two kinds of i.MX ASRC > > > > module > > > > > > Before I spend time on this: are the audio maintainers OK with doing > > > this in V4L2? > > > > > > I do want to have a clear statement on this as it is not something I > > > can decide. > > > > Well, I personally don't mind to have some audio capability in v4l2 > > layer. But, the only uncertain thing for now is whether this is a > > must-have or not. > > > > Thanks, I am also not sure about this. I am also confused that why > there is no m2m implementation for audio in the kernel. Audio also > has similar decoder encoder post-processing as video. > > > > > IIRC, the implementation in the sound driver side was never done just > > because there was no similar implementation? If so, and if the > > extension to the v4l2 core layer is needed, shouldn't it be more > > considered for the possible other route? > > > > Actually I'd like someone could point me to the other route. I'd like to > try. > > The reason why I select to extend v4l2 for such audio usage is that v4l2 > looks best for this audio m2m implementation. v4l2 is designed for m2m > usage. if we need implement another 'route', I don't think it can do better > that v4l2. > > I appreciate that someone can share his ideas or doable solutions. > And please don't ignore my request, ignore my patch. Can you explain a bit more details of your demand? At least, a "big picture" showing how your hardware is implemented and what is exactly necessary would be helpful for understanding the problem. thanks, Takashi