Re: [PATCH 6/6] arm64: dts: qcom: sm7225-fairphone-fp4: Enable USB audio offload support

[Konrad Dybcio]

On 4/25/25 12:44 PM, Luca Weiss wrote:
> Enable USB audio offloading which allows to play audio via a USB-C
> headset with lower power consumption and enabling some other features.
> 
> This can be used like the following:
> 
>   $ amixer -c0 cset name='USB_RX Audio Mixer MultiMedia1' On
>   $ aplay --device=plughw:0,0 test.wav
> 
> Compared to regular playback to the USB sound card no interrupts should
> appear on the xhci-hcd interrupts during playback, instead the ADSP will
> be handling the playback.

"should" isn't very optimistic - I assume this works for you? > 
> Signed-off-by: Luca Weiss <luca.weiss@xxxxxxxxxxxxx>
> ---
[...]

> +&sound {
> +	compatible = "fairphone,fp4-sndcard";
> +	model = "Fairphone 4";
> +
> +	mm1-dai-link {
> +		link-name = "MultiMedia1";
> +
> +		cpu {
> +			sound-dai = <&q6asmdai MSM_FRONTEND_DAI_MULTIMEDIA1>;
> +		};
> +	};
> +
> +	usb-dai-link {
> +		link-name = "USB Playback";
> +
> +		cpu {
> +			sound-dai = <&q6afedai USB_RX>;
> +		};
> +
> +		codec {
> +			sound-dai = <&q6usbdai USB_RX>;
> +		};

'co'dec < 'cp'u> +
> +		platform {
> +			sound-dai = <&q6routing>;
> +		};
> +	};
> +};
> +
>  &tlmm {
>  	gpio-reserved-ranges = <13 4>, <56 2>;
>  
> @@ -1178,6 +1214,7 @@ &usb_1 {
>  &usb_1_dwc3 {
>  	maximum-speed = "super-speed";
>  	dr_mode = "otg";
> +	num-hc-interrupters = /bits/ 16 <3>;
Where does this number come from?

Konrad