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([37.252.94.55]) by smtp.gmail.com with ESMTPSA id gq18-20020a170906e25200b0094eeda0df09sm14749458ejb.179.2023.05.01.03.16.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 May 2023 03:16:37 -0700 (PDT) From: Ivan Orlov To: perex@perex.cz, tiwai@suse.com, corbet@lwn.net Cc: Ivan Orlov , alsa-devel@alsa-project.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, himadrispandya@gmail.com, linux-kernel-mentees@lists.linuxfoundation.org Subject: [PATCH] ALSA: docs: Extend module parameters description Date: Mon, 1 May 2023 14:16:34 +0400 Message-Id: <20230501101634.476297-1-ivan.orlov0322@gmail.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Common ALSA module parameters look a little bit confusing because of the description lacking, and it took me a while to understand the purpose of their existence. To figure it out I asked the question about them to the "alsa-devel" mailing list, and Takashi Iwai answered me with the text I appended to the ALSA documentation in this patch. These common module parameters aren't used a lot nowadays, but as I understand they are important for providing compatibility with some existing user-space apps. So in my opinion it is a good idea to document why we need them. Signed-off-by: Ivan Orlov --- Documentation/sound/alsa-configuration.rst | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sou= nd/alsa-configuration.rst index af71c68f1e4e..829c672d9fe6 100644 --- a/Documentation/sound/alsa-configuration.rst +++ b/Documentation/sound/alsa-configuration.rst @@ -133,6 +133,19 @@ enable enable card; Default: enabled, for PCI and ISA PnP cards =20 +These options are used for either specifying the order of instances or +controlling enabling and disabling of each one of the devices if there +are multiple devices bound with the same driver. For example, there are +many machines which have two HD-audio controllers (one for HDMI/DP +audio and another for onboard analog). In most cases, the second one is +in primary usage, and people would like to assign it as the first +appearing card. They can do it by specifying "index=3D1,0" module +parameter, which will swap the assignment slots. + +Today, with the sound backend like PulseAudio and PipeWire which +supports dynamic configuration, it's of little use, but that was a +help for static configuration in the past. + Module snd-adlib ---------------- =20 --=20 2.34.1