Re: [PATCH 1/3] ASoC: soc-generic-dmaengine-pcm: add option to start DMA after DAI

[Lars-Peter Clausen]

On 2/14/23 08:14, Claudiu Beznea wrote:
> diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
> index 3b99f619e37e..264e87af6b58 100644
> --- a/sound/soc/soc-generic-dmaengine-pcm.c
> +++ b/sound/soc/soc-generic-dmaengine-pcm.c
> @@ -318,7 +318,7 @@ static int dmaengine_copy_user(struct snd_soc_component *component,
>   	return 0;
>   }
>   
> -static const struct snd_soc_component_driver dmaengine_pcm_component = {
> +static struct snd_soc_component_driver dmaengine_pcm_component = {
>   	.name		= SND_DMAENGINE_PCM_DRV_NAME,
>   	.probe_order	= SND_SOC_COMP_ORDER_LATE,
>   	.open		= dmaengine_pcm_open,
> @@ -329,7 +329,7 @@ static const struct snd_soc_component_driver dmaengine_pcm_component = {
>   	.pcm_construct	= dmaengine_pcm_new,
>   };
>   
> -static const struct snd_soc_component_driver dmaengine_pcm_component_process = {
> +static struct snd_soc_component_driver dmaengine_pcm_component_process = {
>   	.name		= SND_DMAENGINE_PCM_DRV_NAME,
>   	.probe_order	= SND_SOC_COMP_ORDER_LATE,
>   	.open		= dmaengine_pcm_open,
> @@ -425,7 +425,7 @@ static const struct snd_dmaengine_pcm_config snd_dmaengine_pcm_default_config =
>   int snd_dmaengine_pcm_register(struct device *dev,
>   	const struct snd_dmaengine_pcm_config *config, unsigned int flags)
>   {
> -	const struct snd_soc_component_driver *driver;
> +	struct snd_soc_component_driver *driver;
>   	struct dmaengine_pcm *pcm;
>   	int ret;
>   
> @@ -450,6 +450,8 @@ int snd_dmaengine_pcm_register(struct device *dev,
>   	else
>   		driver = &dmaengine_pcm_component;
>   
> +	driver->start_dma_last = config->start_dma_last;

This will break if you have multiple sound cards in the system. 
dmaengine_pcm_component must stay const.