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Message-ID: <4ce8ee3b-21d3-4aa3-8fd5-7dcccc2b8abe@linux.intel.com>
Date: Tue, 7 May 2024 16:37:01 -0500
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Subject: Re: [PATCH v21 34/39] ALSA: usb-audio: Add USB offloading capable
 kcontrol
To: Wesley Cheng <quic_wcheng@quicinc.com>, srinivas.kandagatla@linaro.org,
 mathias.nyman@intel.com, perex@perex.cz, conor+dt@kernel.org,
 corbet@lwn.net, lgirdwood@gmail.com, andersson@kernel.org,
 krzk+dt@kernel.org, gregkh@linuxfoundation.org, Thinh.Nguyen@synopsys.com,
 broonie@kernel.org, bgoswami@quicinc.com, tiwai@suse.com,
 bagasdotme@gmail.com, robh@kernel.org, konrad.dybcio@linaro.org
Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
 linux-sound@vger.kernel.org, linux-usb@vger.kernel.org,
 linux-arm-msm@vger.kernel.org, linux-doc@vger.kernel.org,
 alsa-devel@alsa-project.org
References: <20240507195116.9464-1-quic_wcheng@quicinc.com>
 <20240507195116.9464-35-quic_wcheng@quicinc.com>
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From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
In-Reply-To: <20240507195116.9464-35-quic_wcheng@quicinc.com>
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On 5/7/24 14:51, Wesley Cheng wrote:
> In order to allow userspace/applications know about USB offloading status,
> expose a sound kcontrol that fetches information about which sound card
> index is associated with the ASoC platform card supporting offloading.  In
> the USB audio offloading framework, the ASoC BE DAI link is the entity
> responsible for registering to the SOC USB layer.  SOC USB will expose more
> details about the current offloading status, which includes the USB sound
> card and USB PCM device indexes currently being used.
> 
> It is expected for the USB offloading driver to add the kcontrol to the
> sound card associated with the USB audio device.  An example output would
> look like:
> 
> tinymix -D 1 get 'USB Offload Playback Capable Card'
> 0 (range -1->32)

You already gave the following examples in patch 29:

"
USB offloading idle:
tinymix -D 0 get 'USB Offload Playback Route Status'
-->-1, -1 (range -1->32)

USB offloading active(USB card#1 pcm#0):
tinymix -D 0 get 'USB Offload Playback Route Status'
-->1, 0 (range -1->32)
"

Can you clarify how many controls there would be in the end?
Also isn't tinymix -D N going to give you the controls for card N?