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
