Messages in this thread | | | Date | Wed, 8 May 2024 17:13:37 -0700 | Subject | Re: [PATCH v21 33/39] ASoC: usb: Fetch ASoC sound card information | From | Wesley Cheng <> |
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Hi Pierre,
On 5/7/2024 2:33 PM, Pierre-Louis Bossart wrote: > >> +/** >> + * snd_soc_usb_device_offload_available() - Fetch BE DAI link sound card >> + * @dev: the device to find in SOC USB >> + * >> + * Finds the component linked to a specific SOC USB instance, and returns >> + * the sound card number for the platform card supporting offloading. >> + * >> + */ >> +int snd_soc_usb_device_offload_available(struct device *dev) >> +{ >> + struct snd_soc_usb *ctx; >> + >> + ctx = snd_soc_find_usb_ctx(dev); >> + if (!ctx) >> + return -ENODEV; >> + >> + return ctx->component->card->snd_card->number; >> +} > > Presumably there's a notification to help applications discard this > information on removal?
If the platform/ASoC sound card is removed then the USB BE DAI is going to be unregistered from SOC USB. This would lead to the snd_soc_find_usb_ctx() to return with -ENODEV to the USB SND offload kcontrol call.
Thanks Wesley Cheng
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