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Message-ID: <0f903c49-a989-14a6-bac1-c4cae21839eb@quicinc.com>
Date:   Thu, 5 Jan 2023 17:05:54 -0800
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Subject: Re: [RFC PATCH 03/14] ASoC: qcom: Add USB backend ASoC driver for Q6
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To:     Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
        <srinivas.kandagatla@linaro.org>, <mathias.nyman@intel.com>,
        <perex@perex.cz>, <broonie@kernel.org>, <lgirdwood@gmail.com>,
        <andersson@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>,
        <gregkh@linuxfoundation.org>, <Thinh.Nguyen@synopsys.com>,
        <bgoswami@quicinc.com>, <tiwai@suse.com>, <robh+dt@kernel.org>,
        <agross@kernel.org>
CC:     <devicetree@vger.kernel.org>, <alsa-devel@alsa-project.org>,
        <linux-arm-msm@vger.kernel.org>, <linux-usb@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <quic_jackp@quicinc.com>,
        <quic_plai@quicinc.com>
References: <20221223233200.26089-1-quic_wcheng@quicinc.com>
 <20221223233200.26089-4-quic_wcheng@quicinc.com>
 <e29060b1-df65-c0d1-5777-023879a5863e@linux.intel.com>
From:   Wesley Cheng <quic_wcheng@quicinc.com>
In-Reply-To: <e29060b1-df65-c0d1-5777-023879a5863e@linux.intel.com>
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Hi Pierre,

On 1/4/2023 3:41 PM, Pierre-Louis Bossart wrote:
> 
>> +int q6usb_alsa_connection_cb(struct snd_soc_usb *usb, int card_idx,
>> +			int connected)
>> +{
>> +	struct snd_soc_dapm_context *dapm;
>> +	struct q6usb_port_data *data;
>> +
>> +	if (!usb->component)
>> +		return 0;
>> +
>> +	dapm = snd_soc_component_get_dapm(usb->component);
>> +	data = dev_get_drvdata(usb->component->dev);
>> +
>> +	if (connected) {
>> +		snd_soc_dapm_enable_pin(dapm, "USB_RX_BE");
>> +		/* We only track the latest USB headset plugged in */
> 
> that answers to my earlier question on how to deal with multiple
> devices, but is this a desirable policy? This could lead to a lot of
> confusion. If there are restrictions to a single device, then it might
> be more interesting for userspace or the user to indicate which USB
> device gets to use USB offload and all others use legacy.
> 

Yeah, as mentioned its still pretty open ended.  I think from the 
feedback received from Mark/Takashi, this was a viable option for now. 
Would you happen to have any insight/input on how the userspace can pass 
down that selection to the ASoC framework?  Maybe some kind of PCM IOCTL 
call?

Thanks
Wesley Cheng