linux-kernel - Re: [PATCH v15 00/16] Add audio support in v4l2 framework

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Message-ID: <c9d359f3-f1e8-49e6-8118-14894348284c@perex.cz>
Date: Mon, 27 May 2024 09:24:53 +0200
From: Jaroslav Kysela <perex@...ex.cz>
To: Nicolas Dufresne <nicolas@...fresne.ca>, Takashi Iwai <tiwai@...e.de>
Cc: Hans Verkuil <hverkuil@...all.nl>, Shengjiu Wang
 <shengjiu.wang@...il.com>,
 Amadeusz Sławiński
 <amadeuszx.slawinski@...ux.intel.com>,
 Mauro Carvalho Chehab <mchehab@...nel.org>, Mark Brown <broonie@...nel.org>,
 Sebastian Fricke <sebastian.fricke@...labora.com>,
 Shengjiu Wang <shengjiu.wang@....com>, sakari.ailus@....fi,
 tfiga@...omium.org, m.szyprowski@...sung.com, linux-media@...r.kernel.org,
 linux-kernel@...r.kernel.org, Xiubo.Lee@...il.com, festevam@...il.com,
 nicoleotsuka@...il.com, lgirdwood@...il.com, tiwai@...e.com,
 alsa-devel@...a-project.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v15 00/16] Add audio support in v4l2 framework

On 16. 05. 24 16:50, Jaroslav Kysela wrote:
> On 15. 05. 24 22:33, Nicolas Dufresne wrote:

>> In GFX, they solve this issue with fences. That allow setting up the next
>> operation in the chain before the data has been produced.
> 
> The fences look really nicely and seem more modern. It should be possible with
> dma-buf/sync_file.c interface to handle multiple jobs simultaneously and share
> the state between user space and kernel driver.
> 
> In this case, I think that two non-blocking ioctls should be enough - add a
> new job with source/target dma buffers guarded by one fence and abort (flush)
> all active jobs.
> 
> I'll try to propose an API extension for the ALSA's compress API in the
> linux-sound mailing list soon.

I found using sync_file during the implementation to be overkill for resource 
management, so I proposed a simple queue with the standard poll mechanism.

https://lore.kernel.org/linux-sound/20240527071133.223066-1-perex@perex.cz/

					Jaroslav

-- 
Jaroslav Kysela <perex@...ex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.