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Date:   Sun, 14 May 2023 11:21:10 +0200
Message-ID: <877ctb8e0p.wl-tiwai@suse.de>
From:   Takashi Iwai <tiwai@suse.de>
To:     Ivan Orlov <ivan.orlov0322@gmail.com>
Cc:     corbet@lwn.net, akpm@linux-foundation.org, perex@perex.cz,
        tiwai@suse.com, broonie@kernel.org, skhan@linuxfoundation.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        alsa-devel@alsa-project.org, linux-kselftest@vger.kernel.org,
        gregkh@linuxfoundation.org, himadrispandya@gmail.com,
        linux-kernel-mentees@lists.linuxfoundation.org
Subject: Re: [PATCH 1/3] docs: admin-guide: add valsa driver documentation
In-Reply-To: <20230513202037.158777-1-ivan.orlov0322@gmail.com>
References: <20230513202037.158777-1-ivan.orlov0322@gmail.com>
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On Sat, 13 May 2023 22:20:35 +0200,
Ivan Orlov wrote:
> 
> Add documentation for the new Virtual ALSA driver. It covers all possible
> usage cases: errors and delay injections, random and pattern-based data
> generation, playback and ioctl redefinition functionalities testing.
> 
> We have a lot of different virtual media drivers, which can be used for
> testing of the userspace applications and media subsystem middle layer.
> However, all of them are aimed at testing the video functionality and
> simulating the video devices. For audio devices we have only snd-dummy
> module, which is good in simulating the correct behavior of an ALSA device.
> I decided to write a tool, which would help to test the userspace ALSA
> programs (and the PCM middle layer as well) under unusual circumstances
> to figure out how they would behave. So I came up with this Virtual ALSA
> Driver.
> 
> This new Virtual ALSA Driver has several features which can be useful
> during the userspace ALSA applications testing/fuzzing, or testing/fuzzing
> of the PCM middle layer. Not all of them can be implemented using the
> existing virtual drivers (like dummy or loopback). Here is what can this
> driver do:
> 
> - Simulate both capture and playback processes
> - Check the playback stream for containing the looped pattern
> - Generate random or pattern-based capture data
> - Inject delays into the playback and capturing processes
> - Inject errors during the PCM callbacks
> 
> Also, this driver can check the playback stream for containing the
> predefined pattern, which is used in the corresponding selftest to check
> the PCM middle layer data transferring functionality. Additionally, this
> driver redefines the default RESET ioctl, and the selftest covers this PCM
> API functionality as well.
> 
> Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
> ---
>  Documentation/admin-guide/index.rst |   1 +
>  Documentation/admin-guide/valsa.rst | 114 ++++++++++++++++++++++++++++

We have already subdirectories for the sound stuff
(Documentation/sound/*), and this should go to there, I suppose
(unless there is somewhere dedicated for each selftest scenario).


thanks,

Takashi