From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0A518C001DF for ; Wed, 2 Aug 2023 12:10:28 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 5F252832; Wed, 2 Aug 2023 14:09:36 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 5F252832 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1690978226; bh=M5e9aIt4zB+xazIlQzHD++KNXR0lBSq5lPpPZBlFnnU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-Id: List-Archive:List-Help:List-Owner:List-Post:List-Subscribe: List-Unsubscribe:From; b=SErlMacaFtky3hNtFYFI6+DubyhgzHGhYDhex11EnxgpNm64PXLBB5tl8EmkkPCEh sAR9y+LZKUT2xd1UpbyicD76EyW1TenyhQXOut/A6DIi7HSUDOjwQkg+WaIKP2xPOL /cyxyNuCTckqxlmUXcZ+DmzzhD2ZKQ0F1LuLR9KU= Received: by alsa1.perex.cz (Postfix, from userid 50401) id 654DAF80553; Wed, 2 Aug 2023 14:09:34 +0200 (CEST) Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 13B09F80553; Wed, 2 Aug 2023 14:09:34 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 6E26AF80549; Wed, 2 Aug 2023 14:09:30 +0200 (CEST) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id CADF8F8025A for ; Wed, 2 Aug 2023 14:09:25 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz CADF8F8025A Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=n0nVo96Y Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D402D61926; Wed, 2 Aug 2023 12:09:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7BCDC433C8; Wed, 2 Aug 2023 12:09:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690978163; bh=M5e9aIt4zB+xazIlQzHD++KNXR0lBSq5lPpPZBlFnnU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=n0nVo96YwWrmpCF4FJWiUwGfROiwCepHz2+sCu2OSN3CVI7R58tLGqYicwk4YYKOg +NyLJzHU9dFDb2Ho6UPuP2IEP/c/D0cJo7dHvPkGv/B50Ta5mZBFLUrrx0aC9/XNWi +t/sdjYvpddoKhGi/JXjdc+frbE7nFrY66eu014qVGygZQPEEgKavljf8ltRC6P5Nq Xl3zKTbG64yhtVO+lK7S6RXM3ey01oWUYp+6GBs47b5d74fGfCwBb2ahJbqV9qozKI DnSeTdBh7Y9dCBVGiTCZq9YuojTjQKdr2+orJcAcMbvj7a7mpqrt05719eGZTT2qOk sgy/jEHSfCbYA== Date: Wed, 2 Aug 2023 13:09:16 +0100 From: Mark Brown To: Shengjiu Wang Cc: Takashi Iwai , Hans Verkuil , Shengjiu Wang , sakari.ailus@iki.fi, tfiga@chromium.org, m.szyprowski@samsung.com, mchehab@kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Xiubo.Lee@gmail.com, festevam@gmail.com, nicoleotsuka@gmail.com, lgirdwood@gmail.com, perex@perex.cz, tiwai@suse.com, alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [RFC PATCH v2 0/7] Add audio support in v4l2 framework Message-ID: References: <1690265540-25999-1-git-send-email-shengjiu.wang@nxp.com> <47d66c28-1eb2-07f5-d6f9-779d675aefe8@xs4all.nl> <87il9xu1ro.wl-tiwai@suse.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="s7JwRvdQJYqkq6dD" Content-Disposition: inline In-Reply-To: X-Cookie: Humpty Dumpty was pushed. Message-ID-Hash: G5BG3YK2ZPSR6YVJ46T7PNZNRPUFEZOY X-Message-ID-Hash: G5BG3YK2ZPSR6YVJ46T7PNZNRPUFEZOY X-MailFrom: broonie@kernel.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.8 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --s7JwRvdQJYqkq6dD Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Aug 02, 2023 at 08:02:29PM +0800, Shengjiu Wang wrote: > On Wed, Aug 2, 2023 at 7:22=E2=80=AFPM Takashi Iwai wrote: > > 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. This is the thing where we've been trying to persuade people to work on replacing DPCM with full componentisation for about a decade now but nobody's had time other than Morimoto-san who's been chipping away at making everything component based for a good chunk of that time. One trick is that we don't just want this to work for things that are memory to memory, we also want things where there's a direct interconnect that bypasses memory for off-SoC case. > 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 be= tter > that v4l2. > I appreciate that someone can share his ideas or doable solutions. > And please don't ignore my request, ignore my patch. There's a bunch of presentations Lars-Peter did at ELC some considerable time ago about this. --s7JwRvdQJYqkq6dD Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmTKR2sACgkQJNaLcl1U h9DDTwf/Xps9jJnts1SAD46EJPtve2N9sezS1xZvZgz0pluqjz+vDEyh+ediLcCy uoiOc/xZz8Odde64unpb8nKuJzfH8hwdn4JFEMc9capaRijhM9iYxSNlDK6p0wil AX82WXjRdrxyPbNJQgqYehJTbcydxIbewfCqG0ryrG+NeiAPZwR/p1IrCVzBrCZ5 E5+J4oQCAB7li51EuyZuihiImeoDS8LMbPJ5ciHXbhnXyIZaw8AvxTEz9d9llUl8 36hbfxrM24rlJDE16kRco/zHvMkK38W6fubovlGudON8xDoUBFZIPP3SWa5TRy7n j3xcxiC0N3R2xWsDWKC3p7rK6OoiYQ== =0Tfg -----END PGP SIGNATURE----- --s7JwRvdQJYqkq6dD--