Re: [PATCH v4 1/3] docs: sound: add 'pcmtest' driver documentation

From: Takashi Iwai <tiwai@suse.de>
To: Ivan Orlov <ivan.orlov0322@gmail.com>
Cc: perex@perex.cz, tiwai@suse.com, corbet@lwn.net,
	broonie@kernel.org, skhan@linuxfoundation.org,
	alsa-devel@alsa-project.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	gregkh@linuxfoundation.org, himadrispandya@gmail.com,
	linux-kernel-mentees@lists.linuxfoundation.org
Subject: Re: [PATCH v4 1/3] docs: sound: add 'pcmtest' driver documentation
Date: Wed, 07 Jun 2023 15:35:25 +0200	[thread overview]
Message-ID: <87ilbzgztu.wl-tiwai@suse.de> (raw)
In-Reply-To: <20230606193254.20791-1-ivan.orlov0322@gmail.com>

On Tue, 06 Jun 2023 21:32:52 +0200,
Ivan Orlov wrote:
> 
> Add documentation for the new Virtual PCM Test 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 PCM
> Test Driver.
> 
> This new Virtual PCM Test 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.
> 
> The driver supports both interleaved and non-interleaved access modes, and
> have separate pattern buffers for each channel. The driver supports up to
> 4 channels and up to 8 substreams.
> 
> Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>

Now I merged all three patches.

thanks,

Takashi