From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F780179659; Tue, 30 Apr 2024 16:27:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714494480; cv=none; b=PQbrgpJ7H6dar3JhOx1S86bIMtqnAUlPFGkANY76DrI00xH+kyElK60wMNVBJjJKtoAqpWkkWVbFoEiz80bGnEWK+8ztIXK0zUTNxx1JmwKBP0iKoOYVMcnXiA4CgS31yIj8y+F7TqF/lOvVg1Lu/dSuRreDbbvFgB2hDWxG3aQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714494480; c=relaxed/simple; bh=u27bGd4V0G96pi8D9gvQaaGAkmUp7bSeoFGhoO/A8XE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GFr67aXHytL/BgtQups7G56pT1dnJsOl8yuQZdRD4cIXGDlO1o+Y2eROY9gZIME5OkBp3GUBKgKzEteZ0w6M0/iGTEb2q58//FPMTJb4Ufro+xHG6l5KeflqzprLzhSXqOI8yGt2f4C0tSyUCa8Gr0GI1fvi3wrRUcQE3DAjQUU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OCiswKJN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OCiswKJN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B2C0C2BBFC; Tue, 30 Apr 2024 16:27:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714494479; bh=u27bGd4V0G96pi8D9gvQaaGAkmUp7bSeoFGhoO/A8XE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=OCiswKJNOu0sfl6Oov4FuPcbIbdEIAUmabyt1qX3yut7X6jtOUtNez6dT2UiSY6rd UmyD5qSfJyubO8kEyMTErYCZFFaSEvieHPnBf/O2A4ovxK9v590e5J/L2+RHeaDufu 3aLtZ/r7wpN+MjcKfycQd3ZruzmmING/5cJxi/GHSRw/rwljtTiMnDsS3wfXBynfUg B4fyEoVTtsQN7u/8lKgsS41p9O3Kp948p3GmD1zd0hA8sXXiyo/YefgCGzFrpWqMJ/ rBedlv16kTuD1X+QNkL5ru7Fpfk26uvfe2RSEm1+a4lgLtmlZkk9sQ1OLC8jaC+EHZ oFr1SVAafVguA== Date: Tue, 30 Apr 2024 17:27:52 +0100 From: Mauro Carvalho Chehab To: Mark Brown Cc: Sebastian Fricke , Shengjiu Wang , hverkuil@xs4all.nl, sakari.ailus@iki.fi, tfiga@chromium.org, m.szyprowski@samsung.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, shengjiu.wang@gmail.com, 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: [PATCH v15 00/16] Add audio support in v4l2 framework Message-ID: <20240430172752.20ffcd56@sal.lan> In-Reply-To: References: <1710834674-3285-1-git-send-email-shengjiu.wang@nxp.com> <20240430082112.jrovosb6lgblgpfg@basti-XPS-13-9310> X-Mailer: Claws Mail 4.2.0 (GTK 3.24.41; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Em Tue, 30 Apr 2024 23:46:03 +0900 Mark Brown escreveu: > On Tue, Apr 30, 2024 at 10:21:12AM +0200, Sebastian Fricke wrote: > > > first of all thanks for all of this work and I am very sorry for only > > emerging this late into the series, I sadly didn't notice it earlier. > > It might be worth checking out the discussion on earlier versions... > > > 1. The biggest objection is, that the Linux Kernel has a subsystem > > specifically targeted for audio devices, adding support for these > > devices in another subsystem are counterproductive as they work around > > the shortcomings of the audio subsystem while forcing support for a > > device into a subsystem that was never designed for such devices. > > Instead, the audio subsystem has to be adjusted to be able to support > > all of the required workflows, otherwise, the next audio driver with > > similar requirements will have to move to the media subsystem as well, > > the audio subsystem would then never experience the required change and > > soon we would have two audio subsystems. > > The discussion around this originally was that all the audio APIs are > very much centered around real time operations rather than completely > async memory to memory operations and that it's not clear that it's > worth reinventing the wheel simply for the sake of having things in > ALSA when that's already pretty idiomatic for the media subsystem. It > wasn't the memory to memory bit per se, it was the disconnection from > any timing. The media subsystem is also centered around real time. Without real time, you can't have a decent video conference system. Having mem2mem transfers actually help reducing real time delays, as it avoids extra latency due to CPU congestion and/or data transfers from/to userspace. > > > So instead of hammering a driver into the wrong destination, I would > > suggest bundling our forces and implementing a general memory-to-memory > > framework that both the media and the audio subsystem can use, that > > addresses the current shortcomings of the implementation and allows you > > to upload the driver where it is supposed to be. > > That doesn't sound like an immediate solution to maintainer overload > issues... if something like this is going to happen the DRM solution > does seem more general but I'm not sure the amount of stop energy is > proportionate. I don't think maintainer overload is the issue here. The main point is to avoid a fork at the audio uAPI, plus the burden of re-inventing the wheel with new codes for audio formats, new documentation for them, etc. Regards, Mauro